Professor Brian Blais' Blog

Moving....

2011-10-14T08:14:00.000-07:00

So I am trying out wordpress as an alternative to blogger. My new blog is here:

http://brianblais.wordpress.com/

The primary reason I'm doing it is because of the math editing. I can write my posts in LaTeX, run a quick converter (in python!) and get something that looks nice in wordpress. Let me know what you think! If it fails, then it was a worthy experiment.

Mystery, Knowledge, Science and Television

2011-08-03T05:44:00.000-07:00

J J Abrams, the creator of the television show “Lost”, gives a Ted talk where he suggests that sometimes mystery is more important than knowledge. His “mystery box” represents infinite possibilities and hope and that mystery is the catalyst for imagination. He sees the “Lost” television show as a mystery box, always with the sense of possibility.

Now, to be fair, I have not actually seen Lost, so perhaps my comments are unwarranted, but I decided not to watch Lost for the following reason. When Lost was first beginning, several friends said that I would like it. I told them that I would watch it if, and only if, at the end of the series they could tell me that the “plan” for the series actually existed. It was claimed that the series was planned from start to finish, but my friends told me afterward that it was clear it wasn’t, after watching the finale. Too many loose ends, too many mysteries.

I think that J J Abrams learned the wrong lesson about mystery, as represented by his television show “Lost”. It’s not just the mystery, for the sake of mystery, it is the solving of the mystery that yields more mysteries. Scientists are comfortable with not knowing...we are constantly at the edge of what is known and not known. However, what motivates the scientist isn’t the mystery, it is the solution to the mystery knowing that will open up more. There is nothing more dissatisfying than a book, movie, or television show that just opens up more and more “mysteries” and never resolves them...it seems artificial and disorganized. Most people assume that the mysteries will be solved by the end, so they allow themselves to be taken in by the mysteries. However, once it becomes clear that the mysteries are not going to be solved, most lose their attention and become disenchanted.

What made Babylon 5 so engaging was that there was a plan, and you could count on it. You knew that if there was a mystery, that you’d see the resolution of it. I’ll admit that the resolution of the main conflict (the Shadow War) was a bit disappointing, once it happened, but I think part of that feeling had to do with pace and not with the resolution itself. Mystery for the sake of mystery is enough to motivate, temporarily, but not forever. In the real world, solving mysteries opens up more...that’s the real motivator!

Climate and the Moon

2011-07-28T02:45:00.000-07:00

In a prior post I criticize an article on climate which states that current climate models ignore the effect of conduction (i.e. direct contact) and convection, and focus exclusively on the greenhouse gas radiative effect. A comment to that post needs a full response. The comment in full is here:

“I almost bought your discussion until you provided the diagram from Kiehl and Trenberth which is ludicrous. The whole construct here is to create the illusion that the sun cannot heat the earth above minus 18 which is absolute nonsense based on assuming it is valid on geometric grounds to reduce the solar insolation by a factor of 4 then again by the albedo.

If this is valid how then does the surface temperature of the moon reach ~123 C - quoted by NASA.

And how do you explain daytime temperatures on Earth in excess of 50 C as has been recorded ?”

I will focus on the Moon part, just because it is the easiest, but it will be natural to see how to approach this for the Earth as well. First, I must point out the irony of the comment. In trying to defend the claim that the climate models ignore conduction and convection, and focus exclusively on radiation, the comment refers to a system (the Moon) where there is no atmosphere and thus no conduction (except within the ground itself) or convection! Second I have to wonder about how stupid the commenter thinks NASA is. Do they really think that scientists would consider models that are flagrantly in conflict with the most basic observation about the Moon’s surface (i.e. its temperature extremes)? Do they really think that scientists would come up with a calculation that Moon can’t achieve temperatures above, say, -18 C and then stare at 100 C temperature measurements and just leave the calculation as is for decades? Let’s consider how one would develop a model of the surface temperature of the Moon, and it will answer the objections raised in the comment, as well as outline how real science actually progresses.

The Average Blackbody Model

We start with a very simple model of a spherical body out in space receiving input from the Sun to the tune of 1400 W/m2. At the same time, the spherical body emits radiation with a power per square meter dependent on T4 (i.e. the blackbody law).

Notice that in this very simple model we are assuming several things:

that the conduction within the body is instantaneous, thus the temperature of the body is uniform, and the output energy is uniform.
the body is not rotating, so the radiation it is receiving is constant
there is no atmosphere, thus no conduction or convection outside of the solid body
the albedo is the average albedo of the Moon, or a=0.14. Thus this object absorbs 86% of the radiation coming in

I’m not saying this is a good model, but it is a simple one that helps one understand some of the concepts at hand. We will see shortly that it has a number of shortcomings, but for now we’ll see how far we can push it. This is a traditional procedure in science. You start with the simplest model you can write down, push out all the consequences you can until the model breaks, and then introduce the needed complexities to address those consequences (and no more!). Thus, you always have the simplest model that is consistent with as many of the observations that you can.

The total energy out of the body would be the blackbody term shown, multiplied by the total surface area of the sphere: the radiation is outward in all directions. The incoming radiation, however, strikes only one side. Further, it strikes at different angles. Applying calculus one finds that the effective area is simply the cross-sectional area of the sphere, or the area of a circle the same size as the sphere.

We can then write down the change in the temperature, which depends on the material (the mass and specific heat), given the net energy input to the body. I’ll call this dependency K...its exact value, although calculable, will not be important in the model except qualitatively. We then have

When the “energy in” is greater than “energy out”, the temperature increases. When “energy in” is less than “energy out” the temperature decreases. Once it reaches equilibrium, temperature remains constant. What constant? That would be when dT/dt=0, or...

If we look up the values for the actual Moon we get the following:

So our model is not too bad, for the average value, but it could probably be improved. So, now back to the comment which motivated this all:

“If this is valid how then does the surface temperature of the moon reach ~123 C - quoted by NASA.”

The bottom line here is that, if there is an observation that is in conflict with a model, one of the assumptions of the model is probably incorrect, or perhaps you’re comparing the wrong observations to the model. We assumed that the object has a uniform temperature but we know from the 3 data points above (the min, max and mean temperatures) that this is not true! Essentially our model didn’t even attempt to describe temperature variations on the surface, so it comes as no surprise that it is not consistent with them. Many times theorists will use a model, with known deficiencies, because they are interested in different questions: perhaps we are only interested in the average value, and what happens from that average value? In that case, it doesn’t make a lot of sense to include complexities that will be averaged out anyway when we want to answer our question.

To miss this point is to miss the entire process of comparing theory with experiment. It turns out, however, in this case we can make a few simple modifications to explore some of the temperature variation.

The Infinitely Slow Surface-Conduction Model

We use the same assumptions as before, with one modification (in bold):

that the conduction within the body takes an infinite amount of time (i.e. no surface conduction at all). Thus, each patch of surface acts as its own independent object
the body is not rotating, so the radiation it is receiving is constant
there is no atmosphere, thus no conduction or convection outside of the solid body
the albedo is the average albedo of the Moon, or a=0.14. Thus this object absorbs 86% of the radiation coming in

We consider two types of patches: one on the near side and one on the far side.

Near-side patch

Imagine a patch of surface 1 square meter, with the same albedo as the Moon (i.e. absorbing 86%), and a combined mass and specific heat summarized by a constant K’. The energy equation then becomes

at equilibrium we thus have

which again, is reasonably close to the real value. Notice that all we had to do is change the conduction assumption to get surface temperature variation. If you’re concerned that the maximum temperature predicted is lower than the observed, notice that I am using the average albedo of the Moon. There are parts of the Moon’s surface with a lower albedo, and will thus get hotter as a result.

Far-side patch

Now imagine a patch of surface 1 square meter, with the same albedo as the Moon (i.e. absorbing 86%), and a combined mass and specific heat summarized by a constant K’ but with no sunlight at all coming in. The energy equation then becomes

The only equilibrium value for this is T=0. If no energy is coming in, and we have energy going out, the object will keep cooling. So in this model we have the near side T=380 K and the far side T=0 K, at equilibrium.

Although the model is clearly wrong, it demonstrates one thing: you can easily get temperatures above and below the average-model calculation simply by having not all parts of the surface heated equally, and some non-zero time of energy “communication” (i.e. surface conduction or, if you have an atmosphere, conduction and convection with the atmosphere) between the parts. The extreme version calculated here simply demonstrates the effect and is not meant to be realistic.

Adding a Few More Complexities - Qualitative Discussion

We now modify the assumptions as follows

that the conduction within the body takes a finite, non-zero, amount of time
the body rotates once every 28 days, like the Moon
there is no atmosphere, thus no conduction or convection outside of the solid body
the albedo is the average albedo of the Moon, or a=0.14. Thus this object absorbs 86% of the radiation coming in

Although one could set up a simple calculation, or numerical model, to handle this case I am not going to go through the exercise. However, there are two effects that will happen when adding these two changes:

the maximum temperature predicted will be a bit lower than the no-conduction model. This is primarily because the moon rotates the near-side patch out of the the most direct sunlight relatively quickly. If the surface conduction is on the order of minutes, this will make little or no difference. If it is around hours to days then it will. In fact, one could use this difference to help determine the time constant (related to the constant K’) for the surface of the Moon
the minimum temperature predicted will be higher than the T=0 predicted from the no-conduction model. This is both because the moon rotates the far-side patch out of the dark, and that energy from the previously warmed surface will conduct to the far-side patch.

It is fairly straightforward to get a model that is nearly consistent with the observed temperature range, and is consistent with the thermal properties of the surface of the Moon. One can get even more careful by modifying assumption (4), and use the local albedo of the various patches. In addition, one would need to look at all patches on the near-side, taking into account the varying angle of inclination of the radiation. This will not modify the qualitative results.

Conclusions

This all started when I criticized someone’s commentary on climate models, where they claimed that the models exclude thermal conduction and convection, and thus the focus on greenhouse gasses was entirely inappropriate. A further comment claimed that these models put an explicit maximum temperature achievable when they calculate the surface temperature of an object from blackbody equations. The comment further criticized my use of the average model summary for the Earth for this reason.

Notice the procedure we employed to model the system, and address these concerns. We started with a very simple globally averaged model, and got an interesting temperature value similar to the data. We then added a few complexities, such a differential heating, and noticed how this gives a range of temperatures on the surface. We also noticed that the range was half right (half wrong?): the maximum was good, but the minimum was terrible. Adding rotation and non-zero conduction time gives some dynamics and can achieve reasonably close agreement. A more detailed implementation of the local albedo fixes the small errors, especially on the top end. By using this procedure, we can see exactly which parts of our model give which parts of the result. It also shows which parts of the model give the biggest effect, and which are there for small adjustments.

All that is needed to go beyond the average model, and achieve temperature well above the average, is to include differential heating of the surface and some non-zero time of energy “communication”. Once you heat different parts in different ways, and add rotations and time-delays of conductions, you get some interesting dynamics around the average, going both above and below the average. The average calculation is still useful, if you’re not interested in short-term dynamics. It is further useful as a pedagogical tool, because it is a lot simpler. Thus it is not “ludicrous” to use the diagram from Kiehl and Trenberth, as long as one is aware that this is a globally averaged model. If you attempt to infer things well beyond the point of the model, then do not criticize the model - criticize your comparison, and look for a more detailed model that addresses the questions that you’re interested in.

Knowledge and Belief

2011-07-27T02:52:00.000-07:00

I was just directed to this announcement concerning an NSF survey on science literacy. The bottom line is that the NSF is deciding to change the wording of two questions in the survey. The original wording is “Human beings, as we know them today, developed from earlier species of animals,” and “The universe began with a huge explosion.” . The new wording is “According to evolutionary theory, human beings, as we know them today, developed from earlier species of animals” and “According to astronomers, the universe began with a huge explosion.” (emphasis mine). It is noted that there will be a transition period with the questions, with half of the surveys containing the new questions and half the old, to determine its effect.

The stated goal for this change, from the NSF, is to separate knowledge from belief. You might believe that humans are created in their present form, 6000 years ago, but the new questions try to ascertain whether you know that “evolutionary theory” says something different. Is this an important distinction? Is this what we really want to measure? Which is more important for a society? What is the difference between knowledge and belief?

It is quite clear that there will be at least one effect for this rewording: given that the US falls way behind other countries on science literacy, especially with these particular questions, the rewording will most likely increase these numbers with no other work done.

Definitions and Concepts

Beliefs are representations of the world. Specifically, they are representations that we hold to be correct for the real world...as opposed to hopes, which are also representations of the world by not ones that we hold to be necessarily correct. Along with beliefs we always have a confidence in the belief, specified as a probability (either explicitly or implicitly). Knowledge is simply that collection of beliefs that we hold with such high probability or, in other words, with such confidence that we do not significantly doubt them. The belief that the sun rises in the east each morning is considered knowledge for the reason that we hold it with an extremely high probability. This is not just as a result of an inductive reasoning process (i.e. it always has, in our experience, risen in the east each morning) but because it is part of a larger body of knowledge (i.e. astrophysics) for which it is just one consequence within a whole host of other well-established predictions.

Now, on to scientific literacy. The NSF defines scientific literacy as “knowing basic facts and concepts about science and having an understanding of how science works.” Why is it important? Again, the NSF: “It is valuable not only in keeping up with important science-related issues, but also in evaluating and assessing the validity of any type of information and participating meaningfully in the political process.” The question we must ask is, does the new wording measure scientific literacy better than the old wording? To do this, we need to outline the four possible types of people answering the two forms of the questions:

people who answer “yes” to the old and “yes” to the new
people who answer “no” to the old and “no” to the new
people who answer “no” to the old and “yes” to the new
people who answer “yes” to the old and “no” to the new

The wording change doesn’t change cases 1 and 2, adds case 3 to the “yes” category and it introduces the erroneous case 4. The cases can be summarized in another way, like

people who know both that, say, the universe began with a big explosion and that astronomers claim that this is true. This is indicative of scientific literacy.
people who don’t know, or do not believe, that the universe began with a big explosion and that don’t know that astronomers claim that this is true. This is indicative of scientific illiteracy.
people who don’t believe that the universe began with a big explosion but know that astronomers claim that this is true. (more on this below)
people who know that the universe began with a big explosion, but do not believe that astronomers claim that this is true. This might at first seem to be a totally unreasonable and marginal case, but I think it is more significant than perhaps is generally appreciated. These people might think that the new wording is a trick question (e.g. they might think that physicists, as opposed to astronomers, claim that it is true). I’ve had students answer questions in this way, so it is not quite as uncommon as one might think. These students overthink the problem: they know the fact, but are distracted by the extra complexity of the question, thinking that the test is trying to trick them.

Case 3: The Religious Believer

The only reason these particular questions were modified was because of the prevalence of religious belief. How do we know this? We don’t see a proposal to change “The Earth orbits around the Sun and takes a year to do it” to “According to astronomers, the Earth orbits around the Sun and takes a year to do it.” Why? Because no religion (now) has a stake in the answer to that question, and thus have no objection to the claim. Of course, if you go back to the days of Copernicus this was a different story and people were severely punished for too strongly making such a claim. The two questions that are proposed to be changed in this way are precisely the two concepts that crop up in every creationist tract, and are clearly the two major stumbling blocks for a literalist reading of the Bible or the Quran.

Aside from the motivation for the change, we can ask the question whether it is accomplishing something important anyway. Are these Case 3 people, who would answer “no” to the old question but “yes” to the new question, demonstrating scientific literacy? I don’t think so. What they’ve confirmed is that they know that some scientists claim that the universe began with an explosion, but they don’t believe it. This means that they don’t accept the data, or the methods, or both. If the question were about something on the fringes of science, then perhaps this is fine, but it isn’t the case with these two questions. Evolution theory, for example, is as well established as the Round Earth theory and the Germ theory of disease. To deny it is to deny all of the independent work in molecular biology, embryology, ecology, etc... which support it. Even though they may know that fact that biologists support Evolution theory, they have not demonstrated any scientific literacy in terms of “evaluating and assessing the validity of any type of information and participating meaningfully in the political process.” The same can be said of the Big Bang theory, to a slightly lesser degree (i.e. there isn’t quite the volume of completely independent fields of study supporting it, as there is for Evolution, but the data is nearly incontrovertible anyway). To deny either idea is akin to denying the Germ theory of disease.

Bottom line

Imagine someone answering “no” to the question “The world is round” but answers “yes” to “According to geographers, the world is round”. Would they be demonstrating scientific literacy? I don’t think so. Do we want to pander to the religious-motivated ignorance in this country, for the sake of increasing the appearance of scientific literacy? I don’t think so.

Science and Attitudes Toward Criticism

2011-07-26T09:36:00.000-07:00

So this morning I got a strong criticism of my post, “The Not-so-Hidden Flaw in this Climate Argument”, which itself is a criticism of someone else’s criticism of a climate model (got all that?). I only had a very brief moment to look at the comment, but it put me in a good mood...a mood that I don’t think would be held by a similar-type criticism in a non-science arena. I think there is a very big difference between the way a scientist, through training, perceives and handles criticism which was exemplified with my mood this morning. Let me try to explain.

It is a very good day for a scientist to go in to work, and to demonstrate that one of his colleagues is wrong. It’s even better if the wrong idea/theory/model is one that is popular! For those scientists to adequately demonstrate that a popular idea is wrong, we have for them the Nobel Prize. Of course, it is very hard to demonstrate that a well-established idea is wrong because, by definition, a well-established idea in science is one where many many smart people have tried to show it is wrong and have failed. For those people who claim that scientists have a conspiracy to uphold popular scientific ideas (a criticism creationists level against the support of evolution), they completely miss the goals of every scientist.
It is also a good day when someone criticizes your idea. In the comment on my post, the criticism took the form of “if your idea is correct, how do you explain the following observation...”. Awesome! Why? First, someone bothered to read my post, and found it important/interesting enough to comment...that always makes me happy. Secondly, I’m now in a win-win situation. There are 3 possibilities:
- the criticism is flat out wrong, and I get a chance to both teach something, and to bolster my idea...I can be a bit more confident in my idea.
- the criticism is partly correct, and I get a chance to add a bit of nuance, or explore a part of my idea that I hadn’t fully considered
- the criticism is correct, and I have learned something about the world and have to modify my thinking (at the expense of scrapping my idea).

Each of these 3 possibilities is wonderful, and it put me in a good mood! In contrast, most people when criticized (think politics, sports, religion, etc...) get defensive. They don’t look forward to the possibility that they might be wrong, and may need to modify their thinking. I prefer the scientific perspective!

Now I need to go and address the criticism.

Reaping the benefits of science while hostile to science

2011-06-01T17:15:00.000-07:00

So I read with some interest an article by Adam Frank espousing the idea of removing the benefits of science from those who deny science. He starts with examples like “alien visitations to the healing power of eskimo rituals”, and states that there is “no price for them to pay for believing” in these ridiculous things. “They still enjoy the fruits of science, from iPads to modern medicine, even as they profess belief in ideas without any sound basis.” Further, “Science is not a lunch buffet. Yes, the individual results on small, focused issues like the coffee-bad/coffee-good debate may flip back and forth. When research domains mature into overarching paradigms, however, its time to take notice.” Finally, “Don't pick and choose between the science you like and the ones you deny. Chose between science and no science at all.

Hand in your cell phones, please.”

I’ve stated this before, in the form of removing medical treatment for those who refuse vaccines. I am never completely serious, but it is frustrating to see the dichotomy.

The issue I have with this article is one that I’ve written on before here and more here: he focusses on the comparison between evolution denial and climate denial. It really drives me nuts! I am not entirely convinced by the climate data that the situation is as dire as is claimed. I am not sure whether the climate scientists have provided a clear enough picture, without distortion, cherry-picking, and exaggeration. I don’t have to deny all of physics, chemistry, and biology to hold this position as creationists have to do. Perhaps I’m what is sometimes called a luke-warmist, but even on its best days climate science is nowhere close to as well supported as evolution.

Enough! Stop comparing global warming deniers to evolution deniers. It’s a bad comparison, and extremely misleading.

"Frivolous" research in science

2011-05-28T04:43:00.000-07:00

My blog has been languishing for a bit, so I hope to bring it back and be a bit more active.

Someone recently made a comment that they thought that there was a lot of “frivolous” research in science. They said “I don't really care how big the universe is. I am not happier because of that knowledge. My life is no better, nor my parents or my future children.[...] For me, in the end I don't see how it benefits humanity. I would much rather see that time and intellect spent on pursuing ways to improve global living standards, protect the environment, create a better education system, etc...”

My response:

There are several things I could say about this. People are notoriously horrible at predicting which lines of intellectual pursuits will yield real practical results (i.e. direct benefits to humanity). For example, in the late 1800's there was some work done on some pretty obscure mathematical concepts in wave mechanics. At the time there were very few practical results foreseen from this work, if any. However, it later became the foundation for telecommunications, which arguably makes up the bulk of the global economy today. There are many examples like this. That's why it's always good to have basic research funded well, even if it seems frivolous at the time.

Knowledge matters, no matter what it is. Your example about how you don't care how big the universe is, for instance. Let's look at a couple of contrasting beliefs, and their consequences to things like protecting the environment, something you state is important. Person A believes that the world was created specifically for humans, 6000 years ago, and that this creator is making sure things are going along well for his followers (i.e. granting miracles, giving guidance, etc...) Person B believes that the Jesus is going to come again in this lifetime, and the world will end in glory. Person C knows how big the universe really is. This means that person C realizes that 1) the Earth is a relatively small place and 2) there isn't anywhere else we can go if things get messed up here. Which person do you think would be most willing to make difficult decisions to protect the environment for the next, say, 200-300 years?

There are benefits to "frivolous" science. One benefit is in critical thinking, no matter what the topic. Another benefit is the philosophical placement of humans in the grander scheme of things. This can have direct *practical* effects on humanity, and its future. On any topic, truth beats untruth.

Energy Bracelet Experience

2011-03-09T09:01:00.000-08:00

I’ve spoken before about the energy balance bracelets and how they don’t work. I just had an experience at a local flower show where I ran into a vendor of the bracelets. He enthusiastically invited me to a demonstration, exactly like the demos I’d seen before. He was even cooperative when I asked to do the demonstration on him. When I proceeded to knock him over while he was wearing the bracelet (he claimed that I was pushing outward) and failed to knock him over when he wasn’t (he claimed I was pushing inward), he didn’t look too happy. When I pointed out that that was how it worked, he started trying to quote studies, and I amiably walked away.

I am not sure what the best thing to do with these people. I thought about doing what Richard Saunders does, and wear 10 of them (buying them in bulk) and handing them out with a demonstration. That might get me thrown out. Someone suggested I contact the media, a month or so ahead of time for the flower show, and get them to do an investigative piece. Another thing I may do is, if they are willing, is to suggest a very simple blinded experiments. The nice thing about the balance bracelets is that they claim some very simple, reproducible effects. As a result, it is pretty easy to test it in the confines of a vendor booth at a flower show. I will need to come prepared with two identical little bags, and a fake bracelet, in order to do the test. Also, if they claim improved balance, it’d be nice to have a balance test where the the seller is not involved...something like a balance beam, perhaps. I feel confident that I can be a real pain, yet not involve lawyers, in a case like this.

Religion, Scripture, and the Source of Morality

2011-03-08T07:32:00.000-08:00

It is a common argument now from the so-called new atheists that we don’t get our morality from scripture. I am not sure that many religious people, even biblical literalists, would defend such a claim...so in a way it really is a strawman. Francis Collins, following CS Lewis, place morality front and center in their justification for their belief in God, but at no time do they say that it comes from scripture. They claim that morality is, in essence, programmed into us as a gift from the divine creator. The universality of altruism is used in an argument from Collins for a behavior that cannot be selected for, and is thus an indication of a supernatural, moral creator. He never once says that the morality comes from scripture. Seen in this way, then scripture forms a guide which may need to be interpreted for the changing times, even if you are a literalist. I think it would be wiser for the new atheists to ask if scripture can even be a good guide for behavior, without hammering the (strawman) point that scripture is not the source of morality.

Perhaps they should poll their audience on the question of where they believe morality comes from. If a significant fraction states that it comes from scripture, then it no longer is a strawman. I just don’t think it would come out that way.

Wonders in Science

2011-02-25T02:49:00.000-08:00

This is one of the Hubble deep field images:

It is important to note that every little bright smudge on this image is a galaxy with billions of stars. This image is a very small piece of the sky, around 1 out of 150 million, making estimates of galaxies in the visible universe around 100 billion. It is worth pausing and thinking about that. When I think about the majesty of the universe I find it infinitely more inspiring than the parochial, one-world God, of the major religions. Just trying to imagine our place in this vastness, and to imagine that there are other beings out there doing the same thing, wondering if they are alone, there is a sense of awe and wonder that is difficult to describe. Try it sometime: try to grasp, even for a few seconds, what billions of billions of worlds would be like, spread across a space that takes millions of years for light to cross when light can circle the earth in (literally) the snap of a finger.

A Reasonable Perspective on Global Warming

2011-02-24T05:27:00.000-08:00

I’ve read a lot about global warming, taught issues about climate in my classes, and have a decent (but not expert) understanding of the physics involved. Among my colleagues I’m the only one who even entertains the notion that the problem may not be as serious as the media suggests, and I’m the only one who criticizes the IPCC and the “hide the decline” and the extinct polar bears claims.

So it was refreshing to hear this talk by Prof Richard Muller at Berkeley, and to see the Berkeley Earth Project start up. It’s seems to be a reasonable look at what we know confidently, what we really don’t know, and many of the communications failures in the recent years between the climate experts and the public. I was pointed to this talk by Dr Judith Curry’s website, which also seems to be a breath of fresh air on this whole topic. It seems serious and scientific. It doesn’t resort to the hysteria of Al Gore or of Sarah Palin.

I’m looking forward to following these groups more closely in the future.

Does Watson Think?

2011-02-23T03:36:00.000-08:00

There has been a lot in the news about Watson. One article on CNN says “Watson doesn't really ‘think’ anything, and it struggles with simple questions that most humans can answer without a second thought.” They continue, “a question like ‘If a snowman melts and later refreezes, does it turn back into a snowman?’ would be nearly impossible for a statistical reasoning program to tackle.”

Another article on NPR compares Watson to a plant. “Watson, biologically speaking, if you get my drift, is a plant. Watson is big and it is rooted. Like all plants, it is deaf, blind, and immobile; it is basically incapable of directing action of any kind on the world around it.” Continuing, “Giving a plant a camera won't make it see, and giving it language won't let it think. Which is just a way of reminding us that Watson understands no language. Unlike the ant, who acts as though it has reasons for its actions, Watson acts like a plant that talks.”

I think both authors are pretty glib at stating that Watson doesn’t think like us. I am not entirely convinced. When Deep Blue defeated Kasparov in chess, it was stated that Deep Blue doesn’t play chess like a person plays chess. This is true. Deep Blue simply tries all of the possibilities, good, bad, and stupid. Chess masters don’t even see bad moves. Watson is another matter. Sure it compares the words in the question to a big database, but it is doing probabilistic reasoning at its core. This is exactly what people do. So Watson can’t handle very abstract questions, like the concept of melting snowmen, but could a child who has never experienced snow make this leap? We make this leap because we’ve been presented, throughout our life, with a regular universe and our brain has made an internal model of that universe. Watson, too, has an internal model for its universe but the difference is that Watson’s universe is sensory impoverished and conceptually limited.

Watson certainly cannot think as well as we humans, but that is a limitation more of its hardware and the training environment that it is in. But in many ways, Watson thinks just like us.

Creationism and Strawmen

2011-02-21T22:42:00.000-08:00

I can’t tell you how much I cringe when I hear people say, “I just can’t imagine how we developed our complexity through random chance” and similar things, referring (incorrectly) to the “random” process of evolution. This is a strawman argument that is put forward: either total random chance or God. Creationists often do this, but it is also done on the other side.

Take, for example, a recent post I saw on Facebook from one of my friends:

...poses a direct challenge to all creationists. Provide an explanation for vestigial features of living organisms without inadvertently proving evolution.

He was surprised to learn that Answers in Genesis, the go-to place for all things creationist, had a position on vestigial features. That description made use of arguments from molecular biology, and so-called microevolution. It seems as if it is a common misunderstanding that creationists reject all of the apparatus of evolution and microbiology, and a simple, strawman statements like “creationists reject evolution” don’t hold.

It really does help to look at the best arguments from each side, to really see the limits of the analysis. Going back and forth between Talk Origins and Answers in Genesis is a good way to explore the arguments. For example, in transitional fossils we look in Answers in Genesis and find articles like this one and this one which steep of arguments from authority, claims without evidence, and cherry-picking. Many of the arguments rest on criticizing small details on a small number of fossils. In the talk origins article on transitional fossils, we get a very detailed, and seemingly complete, list of transitions from all major animal types. It comes in many parts, and details the characteristics on each transition.

Try it yourself! Pick a topic, go through and find the best arguments each has. It’s a very good exercise. Throw in a good dash of the baloney detection kit, and you’re on your way.

Wonders in Science

2011-02-18T07:17:00.000-08:00

There is a tendency for scientists to be killjoys, raining on everyone parade, poo-pooing cherished beliefs and activities from acupuncture, religion, ufo’s, and homeopathy. Where is the wonder, the joy? I’ve had someone, after a particular session debunking UFO shows on the history channel, say “But wouldn’t it be great if they were true?” Yes! But I don’t want to give up intellectual honesty for wishful thinking. If it’s true, that’s great, but I won’t reduce my efforts to debunk it just because I’d love it to be true. In fact, wanting it to be true motivates me even more to be skeptical, knowing that I’ll be less critical of something I want to be true (as most humans are).

Here’s at least one piece of wonder in the Universe. See the Earth in this picture?

This is a picture of Saturn, with the Sun behind it, taken from the Cassini spacecraft. See that little white speck in the rings, in the upper left? That’s the Earth! There are two responses I have when seeing this picture.

1) We’re really small and insignificant in this Universe
2) What an amazing thing that we can create something on the Earth, send it a billion miles, and be able to take a picture of ourselves. That’s amazing!

The universe is amazing, both in its magnitude and complexity, and we should feel a sense of awe. All this, without introducing unnecessary constructs such as deities. Although science is often accused of arrogance, I can think of no humbler activity than that which brought us the picture above.

20 Years of Being an Atheist Ends Today

2011-02-17T02:15:00.000-08:00

It was 20 years ago when I made the conscious decision to be an atheist. I had been agnostic before, and then made a decision that it was no longer a tenable position to hold, and that the atheist label was the one that matched my mindset best. Since I became an atheist 20 years ago, I never once regretted the decision. There hasn’t been anything at all that has moved me from that perspective, until this week.

I’ve seen the light, and I’ve realized that in some ways it was the wrong decision to become an atheist. I think it was what I needed at the time, and now it is not. I even changed my Facebook profile!

So, what changed my mind? Sam Harris did, in his lecture on the “Problem with Atheism”. Essentially, it boils down to the fact that we don’t need a word for not believing in something, and that to attach a charged word to it undermines the position. We don’t need, as he says, a name for “non-astrologer”. We just need to espouse the positive virtues of believing with sufficient evidence, for the quantification of uncertainty, of intellectual honesty and consistency.

So, in an effort to be more positive about my beliefs in evidence, rationality, and science, from now on I am not going to consider myself an atheist. If someone asks me if I believe in God, I will say I don’t believe in Zeus, Thor or Yahweh (or any of the other gods we’ve heaped on that pile we call mythology). If asked what religion I am, I’ll just say “None”.

The Role of Humanity into the Future

2011-02-16T05:36:00.000-08:00

Yet again, IBM is creating AI to best humans in a task that has been, perhaps, a symbol of uniquely human activity: Jeopardy! The system, Watson, is doing quite well against the humans. The number of applications for this technology is nearly endless.

I’d wonder how this success will play into the broader discourse on the human intellect, and our view of ourselves on the universe. When Deep Blue defeated Kasparov, and the computer became (unofficially) the world chess champion, I remember having mixed feelings. We like our icons, I suppose, and hate to get rid of them. It’s like growing up, and losing Santa Claus, perhaps. The history of science has been to deflate human arrogance, and yet successes like Deep Blue and Watson are not quite the same because it is our own ingenuity which created them.

On some level, Watson feels like a different accomplishment than Deep Blue. Chess is deterministic, well formulated, and complex. It’s complexity is the only thing that challenges an easy computer solution, which was accomplished finally by brute force: get enough fast hardware attacking a well-described problem and you win....always. Watson isn’t nearly as well defined as chess, or at least it doesn’t appear to be as well defined.

Watching Watson, there is a creepy sort of feeling, probably due to too many evil AI movies (2001, Terminator, Matrix, etc...). Kids growing up today will have this sort of technology as the norm. All-in-all, an interesting series of events to keep watching!

Bill O'Reilly, Tides, and the God of the Gaps

2011-02-15T02:50:00.000-08:00

The following link is a Bill O’Reilly interview with David Silverman, President of American Atheists:

http://www.youtube.com/watch?v=3XEgkViLbTk&t=1m40s

I love the look of shock on David’s face right after the “tides go in, tides go out, never a miscommunication. You can’t explain that.”. I think, however, David is completely ineffectual at conveying his point and looks like a jerk. As a followup, Bill responds to a letter in this video:

http://www.youtube.com/watch?v=UyHzhtARf8M

Here he concedes that the Moon causes the tides, but then adds a number of other questions:

Where did the Moon come from?
Where did the Sun come from?
There is order in the universe. Where did we, in all of our intricacies come from?
Why life on this planet and not on the other planets?

He states that, given this observed order in the universe, that it takes more faith to believe this was all luck, rather than in God.

Although many scientists would laugh at these questions, that is the wrong response. These are reasonable questions! They are ignorant and (because Bill should have done a bit of research before asking them), uninformed questions but they are reasonable first-questions one asks. If one is honest about getting answers (which I don’t think Bill is), there are ready answers to these direct questions but it seems to me that the intent of the questions is a bit different.

First he says we can’t explain the tides. So we explain the tides, with gravity and the Moon. Then he asks “where did the Moon come from?” He could have just as easily asked “where did gravity come from?”. It is clear from this line of questioning that there will never be a final answer to satisfy him. Each time we answer one, there will be concepts that that one builds on, etc...

This is classic God-of-the-Gaps, but it is something that I think needs to be dealt with in a more subtle way than David Silverman and many other atheists seem to do. I think most people, rightly, have a sense of wonder about the amazing order in the universe. I think most people immediately attach this order to a creator, the nearest cultural deity, because they don’t have any alternative: they are not informed. In order to dissuade them, I don’t think that insulting their deity is effective because they take that as insulting their sense of wonder, and then science seems like a sterile, arrogant, unimaginative bully.

We need to find a way to enhance their sense of wonder, and yet dismantle the notion that this requires some external deity. We need to keep the spirituality, as a secular notion espoused by Carl Sagan, Sam Harris and others, because that is what is really driving the issues for most people and we need to push the use of the deity farther and farther away from daily life. Science has to be seen as a creative endeavor, one which fully respects the wonder and awe we all see and feel as we ponder the universe.

Why I Can't Support the Darwin Day Resolution

2011-02-12T09:12:00.000-08:00

So I received a tweet asking for support for the Darwin Day Resolution.

The full text of the resolution is here:

Expressing support for designation of February 12, 2011, as Darwin Day and recognizing the importance of science in the betterment of humanity.
Whereas Charles Darwin’s theory of evolution by the mechanism of natural selection, together with the monumental amount of scientific evidence he compiled to support it, provides humanity with a logical and intellectually compelling explanation for the diversity of life on Earth;
Whereas the validity of Darwin’s theory of evolution by natural selection is further strongly supported by the modern understanding of the science of genetics;
Whereas it has been the human curiosity and ingenuity exemplified by Darwin that has promoted new scientific discoveries that have helped humanity solve many problems and improve living conditions;
Whereas the advancement of science must be protected from those unconcerned with the adverse impacts of global warming and climate change;
Whereas the teaching of creationism in some public schools compromises the scientific and academic integrity of the United States’ education systems;
Whereas Charles Darwin is a worthy symbol of scientific advancement on which to focus and around which to build a global celebration of science and humanity intended to promote a common bond among all of Earth’s peoples; and
Whereas, February 12, 2011, is the anniversary of the birth of Charles Darwin in 1809 and would be an appropriate date to designate as Darwin Day: Now, therefore, be it
Resolved, That the House of Representatives—
(1) supports the designation of Darwin Day; and
(2) recognizes Charles Darwin as a worthy symbol on which to celebrate the achievements of reason, science, and the advancement of human knowledge.

I was reading it with some interest, but then I get to the part about “the adverse impacts of global warming and climate change”. Why is climate change in there? There are so many obvious, uncontroversial topics directly related to evolution in medicine, pharmaceuticals, ecology, physiology, etc... that it seems to be both irrelevant and counterproductive to include it. Sure, the climate change folks think that denying it is like denying the holocaust or denying evolution, but it really isn’t nearly at that level. There are not the number of independent investigations and data supporting man-influenced climate change as there are for either evolution or the holocaust, even if the science were completely unambiguous on the topic (which it isn’t). To conflate the two is a serious tactical mistake, and a serious scientific mistake.

Although I support Darwin Day, I can’t support this resolution because of this ridiculous add-on.

The world is flat!

2011-02-11T08:52:00.000-08:00

So, I was listening to a Cosmos episode when Carl Sagan described the method that Eratosthenes used to calculate the circumference of the Earth. He stated that, on a flat Earth, with the light from a far-away object like the Sun all shadows would be the same length. Seeing different-length shadows, as Eratosthenes did in his famous Summer Solstice observation, allows you to infer curvature. But the big assumption here is that the light is coming from very far away. If we had a flat Earth, it is easy to set up a situation where the Sun, directly overhead in some place, casts a 7 degree angle 800 km away as Eratosthenes observed.

This simple arrangement results in a distance to the Sun of about 6500 km. The world is flat!

So, we have two different explanations of the observations. How do we distinguish between them? Answer: the way it is always done in science - spin out the consequences of each, and make predictions where they disagree.

It is easy to show that continuing this calculation would result in some striking predictions. First, given this distance, and the fact that shadows change over the day, the apparent size of the Sun would be very different from one location and another...and it is never observed to be different, even across years. This suggests a very distant Sun. Further, you’d have to make sure that the Moon was closer than the Sun (inferred from eclipses) in both models. Once you do this, then you have two objects with the apparent size problem in the flat-Earth model, again not supported by observation. There are probably many other predictions this model makes which could easily have been verified by the ancients, so it is no surprise that they did not consider it in their calculations.

It is useful, however, to think about the consequences of models beyond the data they agree with.

A modest proposal about uncertainty

2011-01-29T08:35:00.000-08:00

Joan Roughgarden in Beyond Belief made a very astute observation of a problem, and then proposed a lousy solution to it. The problem she was addressing had to do with the public perception of evolution as something quite uncertain scientifically (“theory vs fact”). She observed that the public sees science changing its stance on many things, especially in medicine. One day, you should eat bran. The next, bran is bad for you. The next, bran is good for you again. As a result the public observes that some sciences are uncertain, and can’t distinguish one field from another or one type of claim from another, so they apply doubt to all of science even when it is not warranted by the science. Her solution involves using religious analogies, interpreting phrases in the Bible to explain things like natural selection and mutations, in order to communicate it to a group of people who share and value that vocabulary. Dawkins rightly chews her out for this approach, pointing out how far she is stretching the meaning of the phrases just to fit her philosophy.

The problem she is stating, however, is quite real. How can we expect the public to make decisions about medicine, global warming, evolution, the big bang, etc... when they (somewhat rightly, somewhat wrongly) observe that the scientists themselves are arguing about it? The Intelligent Design folks are currently using this observation to sow doubt with the public in their efforts to “teach the controversy” of evolution to inject creationism into the schools. It is a failure of the scientists, and the media that covers them, to communicate with the public. Can we do better?

I have a proposal, which I’ll sketch out in a toy example. The problem is not the communication of facts, or even of the procedures of science. The problem is with the communication of uncertainties. In day to day life, we easily handle claims with different levels of uncertainties. The sun rises in the east each morning has low uncertainty. The claims of the auto salesman or the politician have higher uncertainty. Quantifying it is, of course, more challenging but the qualitative features of uncertainty are known to nearly everyone. So scientists and journalists really need to take efforts to communicate the uncertainty of every claim, not just the fact of the claim or how the new observations differ from the old observations. How could this be done? I think, at least roughly, one should include a plot of the probability distribution with any claim. One doesn’t need to know advanced math to see the picture. If every claim is accompanied by a plot of the uncertainties, the public will get used to reading them. Let me demonstrate with a toy example.

Say, I am trying to determine the origin year of homo sapiens. I realize there isn’t just one year, and there is a process, but it is not much harder to include those in this simple analysis. I have several homo sapiens fossils where I’ve measured the age, which allows me to calculate my best guess of the age, and the distribution of my uncertainty shown here.

I’ve used a normal, Gaussian, distribution here although in fact it probably should be something skewed left and probably a lot flatter to reflect our greater uncertainty with age, and that we have other observations that put confident lower limits on the origin of homo sapiens. Again, the details aren’t important because all attempts at clarifying the distribution only further help with communicating the uncertainty to the public. A few observations are in order here:

there are many possible values for the origin that lie well outside of our data yet have non-zero probability
Our “best guess” is around the middle of this distribution, but it really can’t be interpreted as “homo sapiens originated 250,000 years ago” as it might read in a newspaper

Now, we have a new paper that adds another fossil much older than than the previous ones, around 340000 years ago. Newspapers may claim “origin of homo sapiens 150% older than originally thought”, or “estimates of the origin of humans overthrown by new data”. How might it look with the uncertainties plotted?

There are a number of lessons that can be read from this.

the new data updates our “best estimate” by only a little - the old data, combined with the new data, are used for the estimate
our uncertainties have widened - by having a larger range of data, our uncertainties may have increased with new data.

In reality, estimating an origin (first event) will update a bit differently than this example shows. For example, the uncertainties in the right-half of the distribution may not be affected at all by an older observation. If this data were in medicine, however, and we were estimating the effect of some new treatment, then the update would be very similar. A single result of a strong effect may not increase our best estimate for that effect by a huge amount. The uncertainties in many medical treatments, or dietary recommendations, straddle the origin: there is significant probability for no effect. It would be fruitful to see the plot of uncertainties, pushed a little this way and that, updated in perhaps a wiki style by scientists as new data come in. There would be many lessons, all of which would help the public understanding of science.

observations rarely overturn well-supported scientific understanding
not all topics have equal uncertainties - doubting everything the same amount is not rational
certainty is never an option, but sometimes the uncertainty is so low that there is a practical certainty
nature itself, not authority, determines our best guess and some of our uncertainty
if the thing you are measuring has a small effect, then you should expect a series of measurements of the effect to change sign: bran is good, bran is bad, bran is good, etc.... This doesn’t mean that the scientists are waffling, it only means that the effect is small and difficult to detect - and probably meaningless.

I think the public could learn to, at least qualitatively, understand and use plots like these. Perhaps there is a better way to display it that does not do violence to the truth, and I’d be open to that. I think getting in the habit of making plots like this would be good for the scientist as well, forcing them to address and communicate the actual uncertainties in their claims.

The Economics of Religion: More good than harm?

2011-01-29T06:14:00.000-08:00

There are some that argue that religion should be eliminated because of all of the harm it does, such as the suicide bombings, honor killings, the Inquisition, etc... This includes the “New Atheists”, like Sam Harris and Richard Dawkins. Others counter that this one-sided perspective ignores all of the good that religion does, such as support for people when they are ill, the donations to natural disaster funds, etc... They argue that religion does more good than harm. This sort of argument is used in economics, and is similar (although not identical to) a cost-benefit analysis. One can focus on, for example, the harm that cars bring in pollution and pavement like environmentalists do or one can focus on the benefits of cars like the access to better health care, the allowance of critical population densities to support significant industries like the industry reps would do. An economist would then weigh both sides, benefits minus costs, and see which to prefer.

In order to do this with religion one cannot simply take the good of religion subtract the bad, come up with a positive number, and say that religion is a benefit to society. It’s like saying that the treatment for the measles is two aspirin and some juice resulting in more cases of recovery than death and saying that we shouldn’t replace this treatment with something else. As is turns out, for the measles, a vaccine will prevent nearly all contractions of the disease, and virtually all deaths.

If we replace religion with a rational perspective (as Sam Harris proposes), which includes a respect for spiritual experiences but not the supernatural explanations of them, then it may be that we essentially vaccinate people against such behavior as suicide bombings, honor killings and inquisitions.

Rounds in Australian Open

2011-01-19T06:00:00.000-08:00

In a previous post, I included predictions for Round 1 of the Australian Open. I am posting the next Rounds' predictions here.

Round 2

Upper	Lower

Round 3 - Given Jan 20, 2011

Upper	Lower

Predictions for the Australian Open

2011-01-18T15:53:00.000-08:00

I am not really into sports, but a student of mine is doing a project on developing an automated system for predicting professional tennis matches. We are posting his system's predictions for the Australian Open. I'll post more, before each round as the results come in. I just want the predictions to come before the events! (I'm a bit late for that, but I did receive the file two days ago. :) ). How well does it do? You'll have to stay tuned!

Upper	Lower

Religion, Science, and Humility

2011-01-14T09:23:00.001-08:00

I've been listening to the "Beyond Belief" workshop, where many very bright people discuss the role of science and religion in society. I need to go back and re-listen to some of them, but I was struck by the attached clip from the very end of Session 4.

In this 5-minute audio clip, Darren Schreiber, UCSD Political Science, make the point that science shows little humility. He continues to claim that his religion is what motivates him for humility, to face the unknown with a humble, searching perspective.

His comments are followed up by Ann Druyan, the wife of the late Carl Sagan, in which she essentially says that science and its methods promote the utmost humility. We are not afforded absolute truths, and if whatever knowledge that we are most confident in gets disproved then science will give its highest honor to the person disproving it. She points out that science brings us out of a childish narcissism, a key part of nearly all religions, which demands that we are central to the universe.

Francis Collins, Science and Religion: How Religion Halts Science

2011-01-10T05:50:00.001-08:00

In reading Francis Collins' book, "The Language of God", I was struck by the way in which the religious claims enter into the scientific discussion. There were three main arguments that he used:

The parameters of the universe (e.g. speed of light, gravitational constant, etc...) are extremely finely tuned for the support of living beings, and is unexplainable through science
Our sense of morality (especially pure altruism) is unexplainable from the perspective of evolution
Our universal longing for God is unexplainable from the perspective of evolution and rational thought

Each of the arguments has the same form: "I don't know how to currently explain something, therefore it is unexplainable in principle, therefore there must be a God." Taken to its extreme, we can find Colbert's summary "There must be a God, because I don't know how things work." particularly appropriate.

It's really a bold religious statement, ironically full of the arrogance that religious people often attribute to scientists. By saying that our current knowledge cannot explain something, therefore it can never be explained, is stating that you know better than all other future generations of people.

The problem with the statements, however, is not the arrogance. It is that they are show-stoppers: once you make the claim that something is unexplainable, then you stop looking. So-called Intelligence Design suffers from the same problem: by saying that a designer is needed to create the stated irreducibly complex mechanisms, then there is no use in searching for an explanation. It stops science, stops curiosity, stops investigation.

These types of arguments, then, are not just wrong they are dangerous because they stop the types of inquiry that could possibly show that they are wrong. In this way, they have a tendency to protect themselves in the world of memes.

I am not saying that we have answers to points 1-3 above (although I think we have some very good ideas at least for 2 and 3), but to go from ignorance to "God must have done it" is extremely sloppy logic, if it can be called logic at all.

A Moral Argument for God

2010-12-30T07:53:00.001-08:00

I recently listened to an interview with Francis Collins on Point of Inquiry, concerning his book The Language of God: A Scientist Presents Evidence for Belief. Francis Collins is an icon of the "scientist who is also Christian" (along with Ken Miller). He's a converted atheist, now evangelical Christian, but is pro-evolution, director of the NIH, and the former director of the Human Genome Project. I was immediately struck by two things:

he was converted to Christianity primarily by the arguments in Mere Christianity, by C.S.Lewis. In this book, one of the main arguments centers around the Moral Law, it's universality and internal (to the human) nature of it. I'll go into that more later.
he is obviously a very smart guy, so his opinions (especially on evolution) need to be taken seriously (at least once). So when he claims that the Moral Law cannot be the product of evolution, one had to at least not write that comment off immediately.

So, I went back and read Mere Christianity, which I had done in college some years back. I had an immediate visceral reaction against it, as he laid out these philosophical arguments that seemed much more like word games and bald assertions than anything approaching truth. I admit that I am steeped in the methods of science, and find arguments that claim surety yet are not testable to be empty. In reading Francis Collins' book, I have found that his arguments are essentially identical to Lewis', but couched in more modern scientific language. (As a footnote, I was, pleasantly surprised to see that Lewis lumped evolution with gravitation in describing laws of nature.)

Moral Law and the Argument for God

The definition of Moral Law here is:

"denunciations of oppression, murder, treachery and falsehood; the same injunctions of kindness to the aged, the young, and the weak, of almsgiving and impartiality and honesty" [pg 24, Collins quoting from Lewis)

The argument for God based on the Moral Law takes on three components. The three components of the argument are the following:

Moral Law is universal to all human cultures.
Moral Law includes pure altruistic behavior (think Mother Theresa or Oskar Shindler here), which cannot be explained by evolution
Moral Law is internal to humans.

(There is a fourth point, which Lewis ties specifically to Christianity, which is that we often choose not to obey this Moral Law. This sets up the idea of free will, and the idea of sin.)

Why is altruism a problem for evolution? Collins writes:

Agape, or selfless altruism, presents a major challenge for the evolutionist. It is quite frankly a scandal to reductionist reasoning. It cannot be accounted for by the drive of individual selfish genes to perpetuate themselves. Quite the contrary: it may lead humans to make sacrifices that lead to great personal suffering, injury, or death, without any evidence of benefit. And yet, if we carefully examine that inner voice we sometimes call conscience, the motivation to practice this kind of love exists within all of us, despite our frequent efforts to ignore it.

He outlines three common evolutionary arguments for the origin of Moral Law:

One proposal is that repeated altruistic behavior of the individual is recognized as a positive attribute in mate selection. But this hypothesis is in direct conflict with observations in nonhuman primates that often reveal just the opposite—such as the practice of infanticide by a newly dominant male monkey, in order to clear the way for his own future offspring.
Another argument is that there are indirect reciprocal benefits from altruism that have provided advantages to the practitioner over evolutionary time; but this explanation cannot account for human motivation to practice small acts of con- science that no one else knows about.
A third argument is that altruistic behavior by members of a group provides benefits to the whole group. Examples are offered of ant colonies, where sterile workers toil incessantly to create an environment where their mothers can have more children. But this kind of "ant altruism" is readily explained in evolutionary terms by the fact that the genes motivating the sterile worker ants are exactlythe same ones that will be passed on by their mother to the siblings they are helping to create. [pg 27-28]

So, if you accept these points, then Collins writes:

If the Law of Human Nature cannot be explained away as cultural artifact or evolutionary by-product, then how can we account for its presence? There is truly something unusual going on here. To quote Lewis, “If there was a controlling power outside the universe, it could not show itself to us as one of the facts inside the universe—no more than the architect of a house could actually be a wall or staircase or fireplace in that house. The only way in which we could expect it to show itself would be inside ourselves as an influence or a command trying to get us to behave in a certain way. And that is just what we do find inside ourselves. Surely this ought to arouse our suspicions?”
Encountering this argument at age twenty-six, I was stunned by its logic. Here, hiding in my own heart as familiar as anything in daily experience, but now emerging for the first time as a clarifying principle, this Moral Law shone its bright white light into the recesses of my childish atheism, and de- manded a serious consideration of its origin. Was this God looking back at me? [pg 29]

An Analogy

When I read arguments of this sort, especially the last quote from Lewis, I am offended by the confidence of the language from a totally flimsy and untestable statement: "The only way in which we could expect [a controlling power] to show itself would be inside ourselves as an influence or a command trying to get us to behave in a certain way" [emphasis mine]. Really? How do you get that? How can you test that claim? How do you know what options are open for a controlling power? Aren't you already assuming that there is something inside us, beyond natural law (i.e. dualism), in order for this to be true?

I'd like to propose an analogy. I am not sure how far this will go, and where it will break down (as all analogies do), but I think it makes a point. There is a universal law, which I will call the Eating Law. According to this law we as humans have an internal voice telling us that we want to eat fatty foods.

The Eating Law is universal to all human cultures. We differ on the specifics, but we all have the voice telling us what we want to eat (i.e. pringles, Big Macs, etc...)
Eating Law includes pure gluttony as a behavior (think people who eat themselves to obesity and death) which cannot be explained by evolution. how could behavior that reduces life expectancy, mating probability, and health possibly be selected for? There are people who eat so much they can't even move!
Eating Law is internal to humans. We can look at the eating behavior, but we'll never be able to observe the actual urge to eat fatty foods.
We often choose not to follow this law (i.e. we choose to eat salad instead of Big Macs)

This is not simply hunger, which we can see in other animals. It is an urge to eat, even when you're not hungry, fatty foods. Now, re-read Lewis:

“If there was a controlling power outside the universe, it could not show itself to us as one of the facts inside the universe—no more than the architect of a house could actually be a wall or staircase or fireplace in that house. The only way in which we could expect it to show itself would be inside ourselves as an influence or a command trying to get us to behave in a certain way. And that is just what we do find inside ourselves. Surely this ought to arouse our suspicions?”

Now, we have two such laws, the Eating Law and the Morality Law. Which one is the message from the creator? How could we test this? I could probably come up with more examples of universal tendencies which take the form of internal messages to humans, but I don't need to. Coming up with just one is enough to show how this argument is completely empty.

I am perplexed that someone as smart as Francis Collins can't see this. I am further perplexed that someone would be "shocked by the logic of this argument".

Are Science and Religion Incompatible?

2010-12-01T02:59:00.001-08:00

I've recently found pointofinquiry.org, which has a lot of very interesting talks about science and religion, so it got me thinking again. Some of the more interesting talks are:

First off, I need to point out that I am an atheist as well as a scientist. Did my learning of science undermine my religion (I was raised Roman Catholic)? Was I jaded about religion before learning science? Does science promote atheism? These are some of the questions one needs to consider with respect to these ideas. Given my one data point, I can only state a correlation, not a cause-and-effect: that as I got older, and learned more science, I got less religious. However, I can point out several observations I've made about the interplay between religion and science. I think some of the hard-line atheists, in their own personal zeal, make claims about science that are overreaching and not entirely correct. I also think that the accommodationist perspective, stating that science is perfectly compatible with religion is also not correct. Here are my main thoughts.

Science is in conflict with some religions

If you believe that the world is 8000 years old, then you are wrong. Almost all branches of science, from physics, chemistry, biology and geology, agree that the Earth is billions of years old. There really is extremely little wiggle room there. Of course, one can always say that God made the world appear billions of years old, but in fact it really is only 8000 years old. If you do that, then you could just as easily state that the world was made yesterday. Further, it is a challenge to think of a reason why this deception would be need to be done. Finally, from a scientific point of view, it is content-free (CF): it makes no measurable predictions, does not suggest the next measurements to be done, nor is it testable in any way. Science has demonstrated, historically, that CF statements have always turned out to be the equivalent of nothing.

If your religion depends on insisting that the world is 8000 years old, then science is in direct conflict with it. Those religions that have put themselves in the cross-hairs of science, by making specific statements about the universe, are making the error of making the religion able to be falsified. Historically speaking, this is exactly what has always happened with testable religious claims: science shows them to be wrong. The religion then has two choices

reject science (usually hypocritically at the same time reaping all the benefits of science, such as longer life, better health, and increased technology)
call those statements metaphorical, and remove the testable part of the religion that was rejected by science

Most liberal religious faiths have tended to choose (2). The Catholic Church, for instance, has a pro-evolutiuon stance and is in-line with science on many things (a departure from historical behavior). In choice (2), the Genesis creation story is allegorical and not literal, and thus not in conflict with modern biology, especially evolution. They merely state that God had a hand in the process, perhaps, for example, injecting souls into humans some million years ago. The conservative religious faiths which believe in the literal Genesis story, with creation in 7 days about 8000 years ago, try to replace evolution with creationism (in the form of, so-called, intelligent design). They are just plain wrong. Further, because they've stated that their religions depend on evolution being false, they have thus made it possible for science to demonstrate they are wrong. They have then created the conflict between their religion and science.

Other religious claims that are testable, and shown to be false, include:

faith healing
intercessory prayer
special creation

Science is not in conflict with some other religions...but with a caveat

There are many scientists who are religious. Some relatively famous modern ones include Ken Miller, a Catholic biologist from Brown University who testified in the Dover Evolution vs Intelligent Design trial, Francis Collins, the geneticist, and the physicist Freeman Dyson. In each of these cases, we have to be careful in defining their belief. Conservative Christians will often point to highly prominent scientists (such as Albert Einsten) who are religious as evidence of no conflict between science and religion. However none of these people support the anti-science agenda of the conservative Christians, and most believe in a vague, impersonal "God", such as "God" representing the mystery in the universe. A far cry from the person-like entity described in the Bible, but by using the same word (God), these scientists have inadvertently played into the hands of people who would like to misuse the belief for their own purposes.

What is comes down to, as you look at religious scientists (which represent a very small minority), there are two types:

scientists that are in fields far away from the "big-picture" questions (like, say, material science) and can thus maintain two opposite viewpoints at the same time. People are very good at compartmentalizing their thinking.
scientists who have scientifically untestable religious beliefs. this includes the "God=universe" belief, or some vague spiritual belief. Ken Miller falls into this category too...when asked whether Jesus had a Y chromosome (which could test for the virgin birth, for example), he says that he just doesn't have any data on that. Even though some of his tests are, in theory, testable they aren't testable right now and perhaps, practically, never.

But shouldn't science stay out of religious issues? Don't they speak about different things?

Stephen J. Gould (the great) used to refer to "non-overlapping magisteria" when speaking about science and religion. Freeman Dyson refers to science and religion as "two windows that people look through, trying to understand the big universe outside, trying to understand why we are here." I have already touched on part of the problem with this: where religion is testable, it has been shown to be false. All that is left are the untestable parts. To me, this content-free religion is the same as not believing in anything. Perhaps it gives someone comfort to believe in a vague, impersonal spirit "out there", but I dislike using the word "God" when referring to the mystery and wonder of the universe itself. Using this word communicates something very different to different people, and implies something that I believe is unwarranted.

Richard Dawkins, in one of the point of inquiry interviews, shows that this non-overlapping magisteria is really a farce. He puts it this way...imagine if, at some point, we uncover archeological evidence with some molecular biology that gave you evidence for, say, the virgin birth of Jesus. Do you think that the Christian religions in the world would say, "Oh no! Non-overlaping magisteria! We can't use science to speak about religious issues!". Of course not! They'd be screaming it from every church. It's only because there is no evidence for any religious claims that we posit the non-overlap of religion and science.

So, in a nut-shell, where religion and science meet, religion either directly agrees with science (in which case it is redundant) or it is wrong. Most of the testable religious claims have been shown to be wrong. Where they don't meet, religion is content-free. If someone decides to find comfort in that, then that is their issue, and science can't really speak to it. I just don't find any value in it.

Religious vs Scientific Thinking

At its core, however, religious thinking and scientific thinking are nearly opposites. Religious thinking relies on anecdotes, statements from authority, faith without evidence, and mistakes of causation from correlation. Each of these mistakes arise from common human failings of reason and perception, for which the scientific methods have been developed to avoid. To do proper science one does not rely on anecdotes or authority, other than nature as the final arbiter. Evidence is everything, and certain knowledge is never achieved in science (as opposed to religion). So it is no wonder that the more scientific you are, the less appeal religion tends to have. But it also makes you less susceptible to the various guises of pseudoscience and less susceptible to being hoodwinked by cranks and quacks.

It is my opinion, then, that the best remedy for religion is simply to teach as much science as possible and let the religion problem work itself out as a result. I don't think that the in-your-face strategies of the new atheists, such as Dawkins, are particularly effective at reducing religion. It has a purpose for rallying the troops, bringing closeted atheists out, so I wouldn't dissuade him from this approach if he feels that that is the primary outcome he wants. I also don't think we should compromise and say there is no conflict between science and religion, which leads to pandering for political reasons with the truth as a casualty. There are fundamental conflicts between many religions and science, and those should be pointed out even if it is uncomfortable for those believers. Science isn't in the business of making people feel comfortable with their beliefs. Thats the role of religion.

Is -x^2 positive or negative?

2010-11-21T17:29:00.001-08:00

So, is -x² a positive, negative, or undefined quantity for real-valued x? Ask any physicist or mathematician and they will say that it is a negative number for real valued x making things like: exp(-x²) between 0 and 1. That is why it came as a BIG surprise to me that computer scientists don't think that, and a program like Excel will interpret:

=-5^2

as positive 25! After taking quite a while debugging a student problem calculating the normal distribution in Excel, it got me on a quest (and an argument with a colleague) to figure out who else thought this way. I checked Matlab, Mathematica, Python, and Google as well as a calculator on the computer. All interpreted -5^2 (properly) as -25. To do otherwise, I believe, is perverse for any application that is doing mathematical applications. I was directed to this page, which outlines many languages. Pretty much just Excel, COBOL, Chipmunk BASIC and a few small scripting languages take the "unary minus" approach, which makes "unary minus" have precedence over exponentiation.

I am not sure why anyone would consider this a good idea, for working with actual math equations. Of course one could add parentheses, but which is clearer:

y=exp(-x^2)

y=exp(-(x^2))

The second is obviously not ambiguous, but less clear. Anyway, that is the entire reason why we have order of operations, so we don't have to do:

5+(3*4)-(2*3)+(2*(3^3))

So, Excel, come into at least the 20th century and figure out that exponentiation trumps "minus", whatever you want to call it.

Glenn Beck on Science

2010-11-21T17:00:00.001-08:00

The following audio from a Glenn Beck show is illustrative of many things. Although he demonstrates incredible ignonance of evolution in this clip, he makes some good points...they just aren't the points he thinks he's making.

His main points are the following:

"I don't know why it is unreasonable to say this...I'm not God, so I don't know how God creates...I don't think we came from monkeys...I think that's ridiculous...I haven't seen a half-monkey-half-person yet...did evolution just stop?"
"They have to force [the idea of evolution] down your throat...when anybody has to force it, it's a problem...you didn't have to force that the world is round...[...]...you don't have to force the truth..you just keep adding evidence and evidence until it becomes self-evident."

Now, point (1) demonstrates a profound ignorance, willful or otherwise, of the claims of evolution. First, no biologist says we came from monkeys...monkeys and people are just as "evolved" as each other, and that they share a common ancestor which would have both features of monkey and human. We have many of these transitional fossils (for a very nice summary see the Transitional Fossil FAQ). It's really such an elementary error, that he should be thrown off the air just for spreading such ignorance.

However, I would like to focus on point (2) which perhaps seems reasonable: that truth should be self evident, and not have to be forced. In a way, one might think that science works this way because everything should be repeatable, and we don't take arguments from authority. However, there is a problem. Although it is true that the fact that the world is round did not have to be forced (in contrast to the bogus propaganda story about Columbus demonstrating it), one does need to actually look at the facts in order to be able to judge...truth can be self evident but it requires one to actually look at the evidence. Take evolution, for example. If you look at the genetic data showing the differences in base-pair counts between animals, this single number mapped out for all animals demonstrates a tree structure (http://en.wikipedia.org/wiki/Common_descent and http://www.talkorigins.org/faqs/comdesc/section1.html). Now recall that Darwin did not know anything about genetics, so this is a prediction made 50+ years before the measurements. When you actually look at the evidence for evolution it is absolutely self evident. The problem is several-fold:

people refuse to even look at the evidence, choosing instead to willfully remain ignorant thinking they understand it.
There is a certain amount of technical information necessary to understand any science, and that takes work. If you don't want to do that work then you'll remain ignorant of it. As an extreme example, quantum mechanics is definitely true, but it neither self evident nor intuitive (and I don't see conservative talking heads railing against it)

What's the solution? I'm not sure, but challenging people to learn is a start.

A walk down memory lane

2010-10-16T08:06:00.001-07:00

I just found a page on "How to Find a Formula for a Set of Numbers". It's a cool little procedure for taking a series, like:

2, 8, 9, 11, 20

and producing a polynomial to give you the next ones in the series, like:

n³- 17/2 n²+ 49/2 n - 15

where n is the term number, starting from n=1. Try it out! Anyway, it was a method I learned in high school math league, and thought it was so cool I wrote a BASIC program on the old TRS-80 computers to do it. I had forgotten how to do it, and it was fun to see it again. I particularly liked the comment on the page:

"""If someone gives you the sequence, say, "1, 4, 9, 16", you could run them through the above process and get the answer that the person is probably looking for: the rule is n² so the next value is 25. But you could also invent any number as the next number in the sequence, say 42, and come up with a rule for "1, 4, 9, 16, 42". Feel free to work it out. It comes out to:

17/24 n⁴ - 85/12 n³ + 619/24 n² - 425/12 n + 17

and the next term is then 121.

So if you want to be obnoxious, the next time you are given a quiz of "find the next number in the series" problems, just pick any number you like and fill it in, and you'll be completely correct. You'll probably get a failing grade on the test, but you can enjoy the smug satisfaction of knowing you were right."""

I knew a kid who, because of a ridiculous fluke, had to redo some of his middle-school competency tests in high school. So, when presented with a series like 2,4,6,8,... he did this on a test (and yes he did fail the test and have to redo it). He was also shown a number of clocks, and asked what time does this show, and for all of the answers put "analog time".

Power UnBalance

2010-10-08T05:56:00.001-07:00

I love watching infomercials, but always wonder how much the sellers are exaggerating. Take this infomercial for the "Power Balance" bracelet, which is claimed to increase balance and coordination:

http://www.youtube.com/watch?v=A_Ow-ZGMy5o

Now, go to this link which shows you how it actually works:

http://www.youtube.com/watch?v=Piu75P8sxTo

Make sure to watch the whole thing, because they give away the "trick" near the middle. It is useful to go back afterward and watch the first one, now that you know the trick.

The real question, then, is: what should you do if you know a friend is considering buying this, or worse, has already bought it? When I showed these videos in my class, I was told that the football team had purchased them already. When some of my students presented them with the evidence, their response was that they didn't care whether it worked or not.

Astounding!

Multiple Model Comparisons Revisited

2010-09-25T10:51:00.000-07:00

Introduction

In a previous post, I hinted at how to do multiple hypotheses testing, using the ψ-measure. It turns out to be much clearer just using the posterior probabilities. The ψ-measure has a nice intuitive feel for the two-hypothesis case, but becomes convoluted in the multiple hyptheses case. Further, when introducing the application of Bayes theorem for students, I have found it to be clearer to follow the following procedure. We first look at Bayes theorem directly, for N hypotheses:

We then calculate the numerator only, for every possible hypothesis:

calculate the sum of all of these values,

and then normalize

The Octopus, Again

From the Wikipedia article, we have the following data:, which gave us correct=12 out of N=14:

The hypotheses that we consider are the following:

H = “Octopus is psychic, and can predict future (sports) events with 90% accuracy” R = “Octopus makes random choices” Y = “chooses flags with big yellow stripes 90% of the time” G = “chooses Germany 90% of the time”

Notice that both models Y and G, give us correct=12 for N=14 (if the “choosing Germany” chooses Spain in the Netherlands match, because of the similarity). The prior for the psychic octopus is, again, the very generous p(H) = 1/100. The two other non-random models should be more likely, before any data, so I take them to be p(Y)=p(G)=1/20. The random model, being the most likely, has the rest of the prior probability, p(R)=0.89.

Now we calculate the numerators:

Sum the values,

and divide. achieving

Thus, the two flag models went from being rare compared to random to being much more likely than random, and certainly much more likely than psychic. Bayes theorem, properly applied, is a quantitative embodiment of Carl Sagan’s famous quote “extraordinary claims require extraordinary evidence”. It is not just that the evidence must be extraordinary (like 999 correct out of 1000), but the evidence must be extraordinary to address all of the, somewhat rare but possible, hypotheses that would come up as much more likely given the initial result. The process of science is to perform experiments to address these alternative hypotheses.

God and Hawking

2010-09-12T09:44:00.000-07:00

From the book “The Grand Design” By STEPHEN HAWKING And LEONARD MLODINOW

....
Newton believed that our strangely habitable solar system did not "arise out of chaos by the mere laws of nature." Instead, he maintained that the order in the universe was "created by God at first and conserved by him to this Day in the same state and condition."

....

The press is pitching this book as a denial of God, claiming that Hawking has said that God does not exist. The media never seem to get the nuances of logical thinking, and its consequences.

What Hawking and Mlodinow are doing is a modernization of an approach used by Laplace (1749-1827) (http://en.wikipedia.org/wiki/Pierre-Simon_Laplace). He worked on many things, including the dynamics of the solar system. When Newton (http://en.wikipedia.org/wiki/Isaac_Newton) published his laws of dynamics 100 years earlier, he demonstrated that the speeds of the planets could be derived from a simple law of gravity. In this way, Newton connected the Earthly things with the "Heavenly" things. However, it was unclear to Newton whether the orbits of the planets would remain constant (as his religious philosophy would state), or if they would be unstable, change, and possibly fly apart given enough time. He posited that one of the roles of God would be to nudge the planets, here and there, to keep their orbits stable.

Laplace, performing his calculations more precisely than his predecessors, was able to determine that the orbits would in fact be stable, without any extra tinkering. Napoleon, when presented with the work of Laplace, asked him: "M. Laplace, they tell me you have written this large book on the system of the universe, and have never even mentioned its Creator." Laplace replied, "I had no need of that hypothesis."

He did not say that there was no God (although that is what he believed), but that the concept of God was not necessary to explain the things that he was explaining using physics. This included the formation of the solar system from a compressing ball of gas (due to gravity), which then forms the Sun in the center and the planets orbiting around. This is essentially the model still in use today!

What Hawking is doing is basically the same thing, but with the origin of the universe. Essentially the current model allows for the possibility of many universes to simultaneously exist and that, like a lottery winner, our universe supports life. It may seem that the universe is "fine-tuned" to support human life, and that this would support the notion of an intelligent designer, Hawking is making the argument that a designer is not needed with our current understanding. Like a lottery winner stating that the odds of winning are astronomical, and yet they won, and then reasoning that there was some design in this choice even when there wasn't. As long as you have enough people playing (or enough universes) you'll eventually observe the unlikely, and that unlikely winner will feel singled out. Hawking argues that the lottery winner (the life on Earth), is arguing the same way when it invokes a designer when it doesn't need to. Hawking doesn't state "God doesn't exist", because that statement cannot be proven, but he simply states that it is an unnecessary hypothesis for the understanding of the origin of the universe.

Of course, *specific* Gods can be disproven. For example, it is clear from many lines of evidence that the Earth is more the 6000 years old and that there never was a global flood. However, you cannot disprove the notion of a God that creates the universe and is then hands-off, like deists commonly believe. It is completely untestable. It is also unnecessary, according to Hawking. This doesn't make it wrong, it is just unnecessary in the same way that we don't need to invoke the divine when understanding how an apple falls from a tree.

Why pseudoscientists like the chi-square test (and why it shouldn't be taught)

2010-09-01T10:10:00.001-07:00

In a prior post I outlined how orthodox statistics can lead to the either-or logical fallacies common in pseudoscience, like astrology and ufo-ology.

In this post I focus on the &chi² test, it's pathologies, and why it is so useful for a pseudoscientist. The example is lifted from E. T. Jaynes' book "Probability Theory"

The two problems with &chi² are:

it violates your strong intuition in some simple cases
it can lead to different results with the exact same data, binned in a different way

Both of these properties are useful to the pseudoscientist.

Intuition and Chi-square: The Three-sided coin

In each of this case we will have some data, and two models to compare which try to explain the data. Intuition strongly favors one, and &chi² favors the other. One of my favorite problems is the three-sided coin: where the coin can fall heads, tails, or on the edge. Imagine we have two models for a relatively thick coin:

Model A: p_heads=p_tails=0.499, p_edge=0.002
Model B: p_heads=p_tails=p_edge=1/3

And we have the following data:

N=29: n_heads=14, n_tails=14, n_edge=1

Which model are you more confident in? Model A of course! If we use the &psi-measure for goodness of fit with these two models, as defined in my prior post, then we have (remember: smaller &psi means more confident in the fit, just like smaller &chi²):

with &psi_B-&psi_A=26.85 which makes model A more then 100 times more likely than model B (a &psi difference of 20 would be exactly 100 times). Perfectly reasonable. What about &chi²?

which makes model B slightly preferable to model A! Amazing! Where is this coming from? Apparently it is coming from the somewhat rare event of an edge-landing. If our data had been instead

N=29: n_heads=15, n_tails=14, n_edge=0

then we'd have

&psi_A=0.3
&psi_B=51.2

and

&chi²_A=0.093
&chi²_B=14.55

where now both measures agree that model A is superior.

Why do pseudoscientists love the &chi² test?

Answer 1: Because all they need to do is wait for that inevitable, somewhat rare but still possible, data point and &chi² yields a pathologically high value

The &psi-measure and log-likelihood

To understand the other problem with the &chi² test we need to understand what the &psi-measure is doing. As above, imagine we have a set of observations O_i. We define the total number of observed points and the relative frequency of each observation,

The maximum likelihood solution for the probabilities of observing O_i for each class, i, is just the relative frequency of each observation. This is the "just-so" solution, where we estimate the probability of seeing 14 heads in 29 flips as p=14/29. This "just-so" solution will have the closest match, and the highest likelihood (by definition). If we have a model which specifies a different set of probabilities for each class, then it's likelihood is simply

The &psi measure can be rewritten as

So you can think of the &psi-measure as comparing a model with the "just-so" solution (which has maximum likelihood). Further, subtracting one value of &psi with another (for different models) performs the log-likelihood ratio between the models. A proper analysis should include prior information, which can be done almost as easily.

An almost equivalent problem

Imagine that we have a coin with 6 faces, and we are comparing the following models:

Model A: p = [0.499/2, 0.499/2, 0.499/2, 0.499/2, 0.002/2,0.002/2]
Model B: p = [1/6,1/6,1/6,1/6,1/6,1/6]

And we have the following data:

N=29: O=[7,7,7,7,0,1]

where I have listed the probabilities and the outcomes for each face. Notice that, grouping them together in pairs we retrieve the same as the first example. Thus when comparing the two models, with this equivalent problem, we should get the same value. Because the size of the problem changed, the individual &psi values will be different (larger) because there are more terms in the "just-so" solution. However, the difference between the models should be the same. The results are:

&psi_A=11.35 (old value 8.34)
&psi_B=38.2 (old value 35.19)

with &psi_B-&psi_A=26.85 (old value 26.85...the same!), and

&chi²_A=32.6 (old value 15.33)
&chi²_B=11.76 (old value 11.66)

The &chi² for one of the models (Model A) has been inflated quite a lot relative to the other model. This means that, depending on how you bin the data, you can make whichever model that you are looking at more or less significantly different, without changing the data at all.

Why do pseudoscientists love the &chi² test?

Answer 2: Because all they need to do is bin their data in different ways to affect the level of significance of their model over the model to which they are comparing

Still taught?

So, why is the &chi² test still taught? I don't know. It has pathological behavior in simple systems, where somewhat rare events artificially inflate its value, and it can be easily used to prop up an unreasonable model simply by rearranging the data. Why not teach something, like the &psi-measure, which is grounded theoretically in the likelihood principle and does not have such pathological behavior? If you prefer to use the log-likelihood instead, then that would be fine (and equivalent).

I think it is about time to purge the &chi² test from our textbooks, and replace it with something correct.

Orthodox Statistics Conducive to Pseudo-Science

2010-08-31T09:28:00.001-07:00

I have just realized that the thought process used in orthodox statistics is conducive to pseudo-science. It adds, in my opinion, to the long list of reasons why Bayesian inference is demonstrably superior (also see here). Let me show with a couple of simple examples.

Astrology

From this skeptical analysis of some astrology data, listing the numbers of famous rich people in each sign, we see the use of the chi-squared goodness of fit test. The data are:

Sign	Number of People
Aries	95
Taurus	104
Gemini	110
Cancer	80
Leo	84
Virgo	88
Libra	87
Scorpio	79
Sagittarius	84
Capricorn	92
Aquarius	91
Pisces	73
Total	1067

To apply the chi-squared test, we simply compare the above numbers to the expected numbers if completely random, which is 1067 people/12=88.9 people according to:

where O are the observed data and E are the expected counts. Once we have the chi-square value and the degrees of freedom (11 in this case), we can look up in tables to get the p-value:

Normally, this might be the end of the story, given that there is not even close to a significant value (usual cut-off around p=0.05).

Subset of the Data

So, if we only take the extreme values, say:

Sign	Number of People
Gemini	110
Pisces	73
Total	183

then we calculate a different chi-squared, with 1 degree of freedom, and get

Now this is pretty silly: of course, if you take the extreme values of 12 numbers, and pretend that they came from a 2-category situation, then it'll appear more significant. What about lumping 6 points together, say Capricorn to Gemini (the first part of the year) and the second part. In this case we aren't cherry picking, and the sums should be less significant than the individual data. We then have:

Sign	Number of People
Capricorn-Gemini	565
Cancer-Sagittarius	502
Total	1067

And we expect 533.5 people in each category. Notice that we went from (the most extreme) 20 person difference from expected in about 100 to a 30 person difference in 500...closer to the expected. What do we get from our chi-squared test?

The test says that this is significantly different from random, more than the individual data! At least the goodness of fit measure, chi-squared value, went down to denote a closer fit to expected but the reduction in the number of data points changes the test quite a lot.

A different measure

E.T. Jaynes suggests in his book to use a different measure of goodness of fit, the &psi measure closely related to the log-likelihood

Using this measure on the above examples, we get

All data: &psi = 28.9
Extreme data: &psi = 39.1
Lumped data: &psi = 8.1

which is completely in agreement with our intuition. The chi-squared test does not match our intuition, and seems to give significance to things that we know shouldn't be.But what about the test with the &psi-measure? How can we tell whether it is a significant difference? One could, in theory, give an arbitrary threshold but that would not be particularly useful, and would not be what a Bayesian would do. What a Bayesian would do is compare values of the goodness-of-fit measure to different models on the same data. It makes no sense, if you have only one model, to reject it by a statistical test...reject it in favor of what? If you have only one model, say Newton's Laws, and you have data that are extremely unlikely given that model, say the odd orbit of Mercury, you don't simply reject Newton's Laws until you have something else to put on the table.The either-or thinking of orthodox statistical tests is very similar to the either-or thinking of the pseudoscientist: either it is random, or it is due to some spiritual, metaphysical, astrological effect. You reject random, and thus you are forced to accept the only alternative put forward. I am not implying that all statisticians are supportive of pseudo-science, and they are often the first to say that you can only reject hypotheses not confirm them. However, since the method of using statistical tests does not stress the searching for alternatives, or better, the necessity for alternatives, it is conducive to these kinds of either-or logical fallacies.An example of a model comparison, from a Bayesian perspective, on a problem suffering from either-or fallacies can be found in the non-psychic octopus post I did earlier.

The Non-Psychic Octopus

2010-08-27T18:29:00.001-07:00

Introduction

I saw in the newspaper an article about a supposedly psychic octopus, which predicts world cup matches by making a choice between two different foods labeled by the team flags. Paul the Octopus has an impressive record of 12 correct out of 14. Or is it impressive? How can we determine whether this performance is evidence for psychic behavior, or something else. A typical statistical analysis might start with the null hypothesis that the octopus was random, so was choosing the teams with probability p=0.5. The likelihood of getting 12 right in 14 is

which is fantastically strong against the null! Even if you do the p-value test for the the correct data being more extreme, you get p-val=0.00646.

So, we reject the null, and the octopus must be psychic!...(or not)

Bayesian Analysis Against Random

Let's look at this another way, and perhaps we can gain some insight. It will be convenient to talk about odds, rather then probability, and further to use the log of the odds so that this becomes an arithmetic problem. The odds is defined as the ratio of the probability for a hypothesis, H, and the probability for the inverse, not H.

We define the log-odds, or evidence as defined by E. T. Jayes,

A few comments before we commence with more calculation. The prior evidence reflects our state of knowledge before we see the data. How likely is it that an octopus is psychic? Most reasonable people would say highly unlikely. Generous odds would be 100:1 against, although personally I'd probably put it at least a million to 1 against. Let's be generous. That gives us a prior evidence of

If we had been naive, and set equal odds, then this evidence would be e=0. So we start with evidence e=-20 for a psychic octopus (which is strong evidence against it, because e<0), and then we observe the data. If we assume that a psychic octopus is right 90% of the time, and that the only alternative is a random octopus correct 50% of the time, then we have added evidence for each correct answer:

Each incorrect answer gives:

The evidence gets pushed up from the prior with each correct answer, and down for each wrong answer. Notice how wrong answers are penalized more than right answers. This is because the psychic octopus is pretty good (p=0.9). We get a final (posterior) evidence for 12 correct and 2 wrong:

which is about 2:1 odds against the psychic octopus.

More to the Story

Most pseudoscience gets propagated by people who reason naively. They will say that there are two possibilities, say random and psychic, and they they must both be equally likely before the data. So, when rare data is found, they reject random and claim this is evidence for psychic phenomena. This line of reasoning is incorrect for two reasons:

random and psychic are not equally probable a priori - random is much more likely in cases like this
there are more possibilities

We already saw how point (1) can be handled by proper prior information. Point (2), with multiple hypotheses gets mathematically a bit trickier (there are more terms to carry around) and is thus messier, but conceptually is fairly straightforward.

We have two hypotheses so far:

H="Octopus sees the correct future 90% of the time, and is psychic"

R="Octopus chooses randomly."

Let me introduce two more hypotheses.

Y="Octopus chooses flags with big yellow stripes 90% of the time"

G="Octopus chooses Germany 90% of the time"

How would you choose the prior probabilities for these hypotheses? Personally, as I said before, I'd have p(H) way below p(R) by about a factor of a million, but being generous, let's put it about a factor of 100. What about p(Y) and p(G)? I'd say that these might be comparable to random or, if I knew something about the vision of octopi or how the person feeding the octopus might rig the food in the direction of his favorite team, I might even have p(Y)>p(R) or p(G)>p(R). Certainly p(Y)>p(H) and p(G)>p(H). So what happens with the data?

For hypothesis Y, there are N=14 games of which the octopus chooses 12 with bright yellow stripes (there is one where it chose Germany over Ghana and should have chosen Ghana which has a bigger strips, and another with Germany and Spain where Spain should have been chosen). For hypothesis G there are N=14 games and the octopus chooses 12 for Germany (2 teams are chosen that are not Germany, and one match where Germany wasn't a choice and it chose Spain, which has the closest flag). Thus, the data support both of these hypotheses exactly as much as the p=0.9 psychic hypothesis. Therefore, the evidence will push these hypotheses up by as much as the psychic, over the random, and will make the psychic octopus even less likely.

So, when you hear fantastic claims supported with a comparison to random, the two things you must do are:

Ask yourself what the prior probability of the fantastic claim is. Even if a random explanation is very rare, it will probably still be favored against the fantastic claim.
Ask yourself what other possibilities, even if unlikely, could explain the data. Since the fantastic claim is exceedingly unlikely, even somewhat unlikely explanations may be supported by the data more than the original fantastic claim.

A new and content-free model

2010-07-10T17:18:00.001-07:00

In his article "A New and Effective Climate Model", Stephen Wilde (guest posting on Anthony Watts' blog) states his dissatisfaction with current climate models, and proposes another "model" for climate which he hopes will improve the state of climate modeling in general. In the article he has items like:

Solar surface turbulence increases causing an expansion of the Earth’s atmosphere.
Resistance to outgoing longwave radiation reduces, energy is lost to space faster.
The stratosphere cools. Possibly also the number of chemical reactions in the upper atmosphere increases due to the increased solar effects with faster destruction of ozone.
The tropopause rises.
etc...

This list continues for 26 points, not an equation in the mix. So why am I so hooked on equations? Take the first item, and call "Solar surface turbulence" T, and the size of the atmosphere, A. Saying T goes up, so A goes up, could be like:

which would predict a nice linear response. What about this:

or this?

Each of these is a translation of "when T goes up, A goes up", but they have radically different forms, and they have radically different effects. You can't build a proper scientific model in words alone. Words are not precise, and there are many different ways to translate them into something that is precise, that can actually make meaningful predictions.

A model of just words is not really a model, in the scientific sense. Lord Kelvin said it best:

"In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be."

Pascal's Global Warming

2010-06-24T18:40:00.001-07:00

I was just alerted to the following video supporting strong action for climate change:

The argument is a little dated, actually, most famously presented in the 1600's well before global warming was a concern. The video uses a rehash of Pascal's wager, replacing personal salvation with policy to deal with climate change. Essentially it states that, if the worst case scenario is very bad, then it is better to deal with that worst case scenario with the possibility of it being a waste of resources, because the alternative (not doing anything and being wrong) is much worse. In Pascal's case, he was arguing for a belief in God. If you believe in God and he doesn't exist, then things aren't that bad (some wasted time and effort). If you don't believe in God and he does exist, then you're in big trouble. The expected value of your reward definitely is maximized by avoiding the worst-case scenario.

There are several problems with this argument, as it applies to global warming, many of which apply to the original argument as well. First, one has to look at the probabilities of the events, and not just their existence. It is true that one of the following two statements is correct:

there is global warming, and humans are causing it
there is not global warming or humans are not causing it

If we assign probabilities to the individual events, then the correct policy may not be to address point (1), if it is sufficiently unlikely. Further, even if we assume there is global warming, and humans are causing it, both the amount of the warming and impact of the warming are needed for making policy. So, if the warming is most likely 0.5 deg in 100 years, versus 2 deg in 100 years, then the policy choices should be modified accordingly. Even though there may be a slight chance of a catastrophic warming, we do not need to plan for it if the chance is slight enough. Finally, dumping resources into a non-problem is not just a "waste of money", but of lives. The amount of money being discussed here is in the trillions, which can go a long way to fighting problems that we know are here and are a problem (hunger, corruption, extreme poverty, religious extremism, etc...). We have to look at where we need to place resources in the most efficient way to address the many, and serious, problems that we know exist in the world.

Now a similar, but more persuasive motivation for climate change regulation is simple: we are dependent on unstable governments for our energy and our energy sources have serious environmental impacts. These facts are currently costing us two unwinnable wars and an oil spill that will take decades to clean up. If we could divert the costs that go into those wars and industries, and put them into non-fossil fuel alternatives (i.e. nuclear fission and fusion), then we have a chance of significantly improving our national security, environment, and future. So, in dealing with a known, significant problem we can solve another (possible) problem (i.e. global warming) as a bonus.

Religion and Scientists

2010-06-08T08:11:00.001-07:00

A friend of mine posted this Slashdot brief on Facebook, which also links to this summary. The articles both imply a much stronger religiosity among scientists than is traditionally assumed, quoting the work of Elaine Ecklund. Some key quotes from these two short summaries are:

"Fully half of these top scientists are religious. Only five of the 275 interviewees actively oppose religion"

Even among the third who are atheists, many consider themselves "spiritual."

The study reveals that scientists often practice a closeted faith, worrying about how their peers would react to learning about their religious views.

The '"insurmountable hostility" between science and religion is a caricature, a thought-cliche, perhaps useful as a satire on groupthink, but hardly representative of reality,' writes Ecklund.

So, when I read this, I thought "Wow! Half of these scientists are religious? Spiritual atheists? Closeted faith? That's amazing stuff!". So, as a scientist myself, I decided to look at the study itself. I confirmed what another blogger stated: essentially the conclusions come from some "new math", and vague statements.

The study included these results:

34% chose “I don't believe in God,”
30% chose “I do not know if there is a God, and there is no way to find out.”

which equals 64%. So "fully half" must mean "less than 36%". That's some good arithmetic! Oh, and

8% chose “I believe in a higher power, but it is not God.”

So I guess religious doesn't imply belief in God, so it goes in the very vague category. If religious includes a belief in God (and I guess in her book she uses "traditionally religious"), then "fully half" must mean "less than 28%".

So about 25% of all scientists profess a belief in God, compared to a public of about 80%. That's a pretty stark contrast! I'd wager that there must be something (or somethings) that makes this negative correlation between science and religion. I think it is difficult to argue that there is not some inherent conflict between the two given this contrast. What about the closeted religious scientists? Those shouldn't appear in these anonymous polls, and thus do not affect any of these numbers. If a scientist doesn't want to bring up their religion with their peers, then 1) what does that say about the strength of their beliefs and 2) perhaps the religious aspects of their life are irrelevant to their scientific work. The closeted religious were not mentioned at all in the study, by the way.

Spirituality

In another monograph, Ecklund discusses her work. In it she states:

For many of the natural scientists, in particular,
knowledge of the spiritual comes directly from their work. For example, according to one physicist,

When I travel to observatories...and when I finally just have enough time to try to
think of my place in the world and the universe and its vastness, it’s then that I feel
the connection to the world more than I do, say, sitting here in my office. And so that
for me, that’s the closest I can come to a spiritual experience.

This excerpt and the many others like it show that, for some scientists, rather than science
replacing religion, spirituality may be replacing religion.

In this way, it is possible for atheists to be "spiritual". To me, I think this is really bad terminology and easily misused. For most people, "spiritual" implies some some "spirit", or an existence separate from the body. These scientists are making no claim like that, they simply mean a feeling still bound to the biology of our bodies. Unfortunately, by using the term "spiritual" it can be used (as here) to enhance the notion that these scientists are religious, or leaning toward religion, which is misleading at best. A religious friend of mine once recently said that she thought I was spiritual. I thought the term was basically meaningless and ill-defined, and still do.

Religious Scientists

Is it surprising that there are religious scientists? Not at all. Because most of the public is religious, most scientists are raised with some religion. It is also human nature to separate different, conflicting, modes of thinking in different contexts. It is very easy for someone to study superconductivity and not have it interfere or conflict with any of their views of the divine. I've written about religion in other posts, and will only add that I believe that much of religion comes from the skills we have to help our survival: it is better to see a tiger when there isn't one than to not see a tiger when there is one. From there, combine with cultural structures, it is easy to see how religious ideas propagate. The great thing about science is that its methods allow us to transcend these false-positives, and arrive at ways to discern truth from fiction. Because we're human, it doesn't work 100% of the time, but in the long run it has been our most successful human creation.

It is no surprise to me that some scientists are religious. It would have been a surprise to me to hear that "fully half" are religious, and as it turns out that isn't true.

One last TV post, about Battlestar Galactica

2010-06-08T05:06:00.001-07:00

No TV posts for a while after this one...just trying to clear my desk.

There are a number of things that bother me about BSG. This list is here for anyone who
wants to challenge me on any of this, comment please! It's in the form of loose-fitting
notes, written over the course of watching the series. There are spoilers, etc...

1)
Once they find out that Cylons look like us, and they consider a Cylon
detector, they seem to hand the entire problem over to Dr. Baltar.
There seems to be no consideration about whether he is a Cylon, or
in league with the Cylons. What could they do differently? Have the
Dr make something that is independently testable, perhaps by Gaita or
others. They don't even consider it.

2)
I find it straining in the extreme to believe that there is no
straightforward test to tell a Cylon from non-Cylon, given the actions
and words of the various people. Cylons:
1) are stronger than people
2) do not tire
3) are able to be uploaded, at least at death
4) have backs that glow under certain conditions
5) have fiber optic interfaces in their arms!

points 1 and 2 would almost certainly leave indicators in the muscle
cells, as well as brain waves. point 3 on brain waves, and point
4 certainly should be detectable. point 5 should be obvious!

At other points, they say that they are basically indistiguishable,
which to my mind means that they have organic processes (even if
artificially made), and even their brain activity is the same, to the
point of being indistinguishable from a person. If that is the case,
then it seems weird to talk about them having "software, not emotions".
It's a looks like a duck, acts like a duck, every possible measurement
confirms it's a duck, but it's not a duck? Sorry, that's just too hard
to swallow.

So you have the problem that, either, they are very different in which
case they should be detectable, or they are identical, in which case
they are no different than humans. The writers seem to want it
both ways.

What would my solution be? If these models were designed for the express
purpose of infiltratration into the fleet, then there would have been
a lot of work to make them undetectable. I would say that the innards
would be clearly mechanical/organic, with an organic outside. The inside
would broadcast signals to fool scans, like MRI and CAT scans, while
the outside would have blood, sweat, etc... to fool observation there.
It wouldn't be too hard to imagine that the only way to test for such
a thing would entail tests that would be lethal to a person, which
might solve some of the writers' problems.

Whenever someone said "they aren't human, they are machines" I cringed, and wanted
to reply: what do you mean by machines? In which ways are they machines and humans
aren't? throughout the series, the cylons were humans when convenient, and
machines when convenient. I don't think the writers had a consistent vision of
what the cylons were, or wanted.

3) WTF is the cylon plan. They want all humanity destroyed, but then
they seem to want humans for procreation and love. They say they want
to protect Sharon's baby, and then the next episode (!) they launch
an all-out attack on the fleet. They have well hidden spies in the
Galactica who could have done damage to the ship, that was going to
be a museum anyway, and they were unable to destroy it? How hard would
it have been to put one of those Cylon viruses in the computer, dormant,
and then when the fleet was assembled have it relay random jump points
to all of the fleet, and then send the Galactica into a star?

The writers seem to use Cylon attacks, and then Cylon pleasantness or
incompleteness, for convenience. It's back to the "not like us, just
like us" problem above which leads to inconsistent behavior. I think
there was no plan, so these inconsistencies keep compounding over time.

4) In flight of the Phoenix, when they disabled a huge number of cylon
raiders, why didn't they capture some of them for use later? Seems
like a major tactical failure.

5) In the 1st season episode when they were looking for Starbuck, who had
crashed on a planet with a cylon, Com. Adama said to his son that if it
were his son that was lost, that he'd never stop searching. That family
was most important. Why, then, in the last episode, is Com. Adama quick
to leave his son, knowing that Roslin was only going to be around for
a short while, and that both would now be alone.

6) In Pegasus, why is Baltar's angel surprised at seeing a beat-up
number 6? Why does she say "it's me", when it really isn't?

7) if ressurection ships are so important, why not guard them better?
why not have 2 ressurection hubs? why not a more distributed system?

8) how far away really is the Cylon homeworld?

9) in E16 2nd season, Sacrifice, we have people who claim the fleet are
cylon sympathizers and hold hostages. Not 2 episodes before, it was all
about cylon sympathizer groups trying to force gallactica to try to get
peace with the cylons. Each lasts 1 episode, and no more. so much
of this would have been better with a plan, built up over several
episodes.

10) at the beginning of each episode they have a 1-minute "what has
gone before", and then after the credits they have a 30-second flash
of images from the episode. it is as if they don't trust the extended
storyline structure, and they feel that a gimic is needed to entise
viewers to stay.

11) in Season 3 episode 8, Bulldog returns in a cylon raider after
being gone for 3 years. Doc Cottle does a quick DNA test to match it
against his military record, and concludes he's not a cylon. Wow! They
couldn't do that in Season 1? It certainly would have made a huge
difference. As plot holes go, that one is pretty darn big.

12) I find it mindboggling that a race that has mastered organic
technology cannot
a) do a proper quarrantine
b) diagnose a simple virus, that Doc Cottle can in a short while

13) why do the cylons want a new home? why Earth?

14) the incessant use of flashbacks I think is because there isn't a
plan, and this makes it look like there is a consistent backstory

15) the episodes with the coup, ending in the execution of Zarek and
Gaeta...some of the best that the show has had. I'd say, that the best
episodes have been:

Miniseries
Pegasus - Resurrection
New Caprica rescue
Coup (S4ep 13-14)

Notice that these are all the human stories. the cylon stories are not
nearly as good.

16) Episode 15, when Tyrol tells Adama that the ship is slowly breaking
up, and there is cylon tech that can help suddenly Adama is anti-cylon
tech? he changes his mind later, but still, this is inconsistent with
the previous episodes when he was immediately fine upgrading jump drives.
why the sudden change of heart?

17) when the BG makes it's final jump, Adama says: "whereever we are, that's where we're going to stay"

...of course, until the rest of the fleet gets there, and we continue with the
original plan. Why did Adama say this?

18) don't build a city at the end? don't use the technology? that
seems like an idea from an idealist but not very practical - a sure way
to reduce life expectancy in your new home

19) Adama is a cylon. Kara is the harbinger of death. Baltar and Six will be the mother
and father of the human race. prophecies that don't pan out.

20) from someone else, but exactly what I was thinking:
"""
When the season 1 [of Babylon 5] was aired JMS knew why Babylon 4 had
appeared and what
meant the visions saw there... when the first Shadow cruiser appeared
in season 1 he fully knew what it was and who was behind it.. when in
season 1 they talked about why Sinclair was so important and what
secret he had..

All was shorted out in advance.. he even writed "scape doors" in case
some actor stepped out of the series.. like happened with Michael
O'Haire (Sinclair) left at the end of season 1.. he used a scape
door introducing Sheridan..JMS has said he had scape doors for Delen,
Garibaldi, etc..

You think BSG writers knew there was going to be 2 earths?
Or who the remaining 8 models were going to be? Or even that Tigh
and Tyrol were Cylons?... you think they really knew
what the Opera house visions really meant? Or what the plan was?
"""

21) It seems to me that there would be a fool-proof way of killing a cylon
without it able to download: instantly drop it in the engine. unless the
download is able to be done in nanoseconds, there wouldn't be anything left
to download from.

Battlestar Galactica, Lost, and Babylon 5: To Plan or not to Plan

2010-06-08T03:59:00.001-07:00

I'll get back to more academic things shortly, but I wanted to get this one off my chest. I just finished watching the entire series of Battlestar Galactica, which I did in little bits over the course of a year or so (I don't watch much TV, so I catch it when I exercise, and an occasional lunch time). I've always liked science fiction, was a big Trek fan, and followed Star Trek Next Generation from the beginning through all 7 years. I am a huge fan of Babylon 5, which I still believe to be the best Sci Fi ever to be on television (see full episodes here). Battlestar Galactica could have been that, but failed in one very particular way which I'll get to. Other people said that I'd like Lost, but I refused to watch it until it was done, so I could be told whether it failed as well, which I've been told it did in the same way as Battlestar Galactica (BG). How did it fail?

BG failed, not because of budget (which was probably 10 times that of Babylon 5 (B5)), or acting, cast changes, director problems, or writing (which is some of the best I've ever seen), but because they didn't have a plan. BG and Lost claimed they had a plan, but didn't. On the other hand, the creator of B5 shorted out all of the episodes for 5 years, so he knew where things were going from day 1. B5 is the only show that I know of that has done that, and it is (in my opinion) the only way to do long-running shows like these. Why does this make such a difference?

Inconsistencies. When you have a plan, you don't have nearly as many inconsistencies. You're not trying to hack together a concluding episode, trying to make all of the lose ends tie together in some haphazard way, because you knew how they tied together at the beginning. Star Trek Next Generation solved this problem, mostly, by not having any long-running plot lines. Each episode ends with the characters in exactly the same condition as they started. BG had some good ideas, but its resolution seemed like a hack.

Foreshadowing. When you have a plan, you can have foreshadowing. Not just vague, unexplained claims, but real references to future events. In the first episode of B5, a character refers to a prophetic dream they have about their death 20 years from then. At the time the viewer thinks they understand the dream, or think that it is a toss-off comment, but late 3rd season we see some of the details, and late 5th (and last) season we see the lead-up to those events. The flashback method is the poor-man's (or poor planners) way of doing this, basically saying "we need these events to have happened in the past, to make sense of what we want to show now, but we didn't think of it before so we'll show it now". BG used this a lot.

Larger Story Arc. Even at its weakest points, B5 benefited from its plan. A weak single episode was lifted up if it contributed to the larger story arc. In this way, weak episodes were improved because there was a plan, and the entire series seemed more consistent.

Rewatchability. From a marketing point of view, this seems to me to be a no-brainer, although it is almost never done. Once B5 finished, I wanted to go back and watch it again to pick up on all of those things that were planned, but I missed. How much foreshadowing did I miss? How many little details in the background were there that became important, but I didn't realize? How many decisions of the characters contributed to their final roles? How many seemingly throw-away lines were really important? Now that I've finished watching BG, I don't have any urge to watch it ever again. There's nothing new to see. Finding out in season 3 that Tigh is a Cylon doesn't modify your perspective on any of his actions in season 1. None of the fates of the characters can be seen in the early parts of the series. The so-called prophecies are each stated and resolved in a couple episodes, or so vague as to be meaningless.

I've heard that Lost suffers from this same problem: no plan leads to inconsistent storylines, convenient flashbacks, and an unsatisfying conclusion with loose ends.

Now, B5 wasn't perfect. It could have used more money, better actors, better dialog. It's writing can be corny at times, and there was a studio snafu that condensed some of the plot in Season 4, and made Season 5 a bit thinner than one would like. However, the universe is entirely original, and the 5-year plan was just amazing and makes the series hold up well over time.

I now won't watch much of anything without a plan...it's just not worth the ride.

Lord of the Rings

2010-06-07T11:23:00.001-07:00

I have a backlog of blog posts that I wanted to get caught up on. This blog has been pretty academic lately, so I figured a change of pace would be nice. I figured I'd post some of my thoughts on the Lord of the Rings. To set the record straight, I really like the books and the movies, but I noticed something about the movies which disturbs me somewhat: in nearly every case where the movie deviates from the books, it is in the direction of weakening the characters. The more I thought about it, the more I realized that the pattern is held. Here I give a summary list of the changes to the characters. Perhaps there are more examples. Are there any counter examples?

Character	Comment ([M]=movie, [B]=book)
Gandalf	hits his head in Bilbo's home [M] staff is broken by the Nazgul [M]
Frodo	falls down, defenseless, when approached on Weathertop [M] strikes back bravely (although ineffectually) at Weathertop [B] ditches Sam in the middle of Mordor! [M]
Aragorn	nearly gets killed by an orc, and needs to be revived [M] is not strong enough when looking in the Palantir, to counter Sauron (drops it) [M]
Sauron!	information about the attack on Minas Tirith is leaked to Pippin's mind during the contact with the Palantir [M] Everyone knew where the next attack would be, and the attack is rushed due to Aragorn's confrontation in the Palantir [B]
Eowyn	Eowyn is clearly afraid up to and including the battle [M]
Faramir	Faramir is seduced by the ring, and takes Frodo to Osgiliath [M] Faramir is only momentarily seduced by the ring, but quickly comes to his senses and lets Frodo go [B]
Eomer + Minas Tirith	Rohan and Minas Tirith are not enough to combat the first army of Sauron, and need the dead (called by Aragorn) to clear them out. [M] Only the back-up armies and navies of Sauron are cleared out by the dead called by Aragorn, and the Rohan is enough to fend off the armies at Minas Tirith itself. [B]
King Theoden	Theoden needs Aragorn's prompting to help Minas Tirith. [M]

Any more?

Nice talk about science and vaccination

2010-04-19T09:40:00.000-07:00

The site http://www.ted.com/ is a really great site to find talks on lots of different topics. The one I recently listened to is http://www.ted.com/talks/michael_specter_the_danger_of_science_denial.html, which highlights some of the dangers of the recent anti-vax movement. Lots of other great links at http://www.sciencebasedmedicine.org/?cat=36.

The Not-so-Hidden Flaw in this Climate Argument

2010-02-26T06:12:00.001-08:00

There are sometimes people think that I am a global warming denier (I'm not), but I am not entirely convinced that the dire predictions from the global warming camp are supported by the evidence. I am skeptical of conclusions based entirely on models, and I am really skeptical of anything where I perceive less-than-open information exchange combined with vested interests and a lot of money. Given all of that, I feel free to rip apart anyone's argument regardless of which side they happen to be on. :) That's how science works!

So I was pointed to an article called "The Hidden Flaw in Greenhouse Theory" which has such flawed logic itself that I am surprised someone wrote it.

Introduction

To summarize the article, I quote the last paragraph:

An idea has been drummed into our heads for decades: that roughly 1% of the atmosphere's content is responsible for shifting the earth's surface temperature from inimical to benign. This conjecture has mistakenly focused on specifically light-absorbing gases, however, ignoring heat-absorbing gases altogether. Any heated atmospheric gas radiates infrared energy back toward the earth, meaning that the dreadful power we've attributed to light-absorbing molecules up to now has been wildly exaggerated and must be radically adjusted -- indeed, pared down perhaps a hundred times. Because all gases radiate the heat they acquire, trace-gas heating theory is an untenable concept, a long-held illusion we'd be wise to abandon.

How does he come to such a grand conclusion? He starts with a quote of a NASA elementary school guide, which has:

Question: Do all gases absorb heat?
• Answer: No. Only some gases have the unique property of being able to absorb heat.

Then he (correctly) criticizes this guide saying

So how does NASA go wrong? By consistently confusing light and heat, as you see in the illustration below, where infrared light is depicted as heat.

Clearly NASA should have said that greenhouse gases absorb infrared light, or radiation.

Then the author continues with this:

Why does NASA go wrong? Because it has a flimsy yet lucrative theory to foist on the taxpaying public, that's why. As the space agency explains in the Main Lesson Concept, the core idea of greenhouse theory is that downward radiation from greenhouse gases raises the earth's surface temperature higher than solar heating can.

This is amazing. Regardless of ones stance on global warming, the greenhouse effect (badly named) is a well known, well established consequence of the basic laws of thermodynamics. Without it, Earth would be far less habitable!

Conduction, Convection, Radiation, Oh My!

He continues:

To make this idea seem plausible, therefore, it's crucial to fix people's attention on the 1% of the atmosphere that can be heated by radiant transfer instead of the 99% and more that is heated by direct contact with the earth's surface and then by convection.

As a nitpick, it would actually be more like 5 percent or so, because water vapor is the most abundant greenhouse gas. Even so, his argument is fallacious, that a trace gas cannot cause significant warming. Let's take another example of a trace gas that increases atmospheric warming: ozone. In the stratosphere, at the "ozone layer", the concentration of ozone is about 2 to 8 parts per million. That is 0.0002%! Despite this trace amount, we get significant warming of the stratosphere as shown here.

His reasoning on this issue is

Consider too that since most air molecules are infrared-transparent, they can't be heated by the infrared that CO2 and water vapor emit. This means that downward radiation from "greenhouse gases" can only explain how the earth's surface might get warmer, not the rest of the atmosphere.

No one is suggesting that the non-greenhouse gases are being heated by the re-radiation of the greenhouse gasses. They are heated by the collisions with greenhouse gasses, thus raising the overall atmospheric temperature. This feedback loop continues until the new balance, with the surface, is established. It's strictly conservation of energy. Some is radiated, some is lost in collisions, and the gasses in the atmosphere as well as the surface adjust until an equilibrium temperature is reached. A simple process, really.

At the crux of his argument is this:

For meteorologists acknowledge that our atmosphere is principally heated by surface contact and convective circulation.

This is just wrong. What physicist do is follow the money, or the energy in this case. A very simple balance can be shown, quantified, and verified by numerous types of measurements. A very simple picture of it is here.

(From http://oceanworld.tamu.edu/resources/oceanography-book/radiationbalance.htm, which cites Houghton et al., (1996: 58), which using data from Kiehl and Trenberth (1996).)

As a fraction of the 342 units of solar energy coming in, about 168 is absorbed directly but about 324 is absorbed from the atmospheric radiation! The fraction of conduction and convection comes only to about 30%. It is true that the atmosphere gets some energy from conduction, but not most of its energy.

Scientific-sounding Junk

It is a real challenge for people without science background to sift through things like this. It sounds like science, but it is incredibly wrong. One way to help tell the difference is to observe how the author responds to criticism. Concerning the errors, do they offer an errata or do they ignore them, or worse, inject ad-hominem attacks on the critic? Saying that NASA "has a flimsy yet lucrative theory to foist on the taxpaying public" is playing into people's distrust of government, and trying to use that to bolster an argument, without actually strengthening the argument itself. It is implying motive without substantiation. I could do that too by suggesting that the author is starting with an anti-global warming position, and wants to prop it up with whatever emotional verbiage he can get away with to hide spurious arguments. Instead, I simply show how elementary and spurious his arguments are, and predict that he will not submit any corrections. I can point out the ad-hominem attacks on NASA as unbecoming of a scientific argument, and is useful only in a propaganda piece.

Another way that someone might tell if the argument is sound, is what sorts of errors are being raised. If the errors are of a technical nature, like the benefits of particular statistical tests, then it can be hard for a non-expert to tell. However, if the arguments have basic errors that can be confirmed in encyclopedias then it is much easier to tell. If the arguments include non-scientific, emotional, exaggerated language then it is much easier to tell that it is a propaganda piece and not a scientific piece.

Are there other ways that non-experts in a field can decide the merits of arguments? Perhaps someone will comment and add some more, and perhaps I'll think of some more. Mostly, being able to skeptically think like a scientist, regardless of your personal belief in something, is the most important skill to use in cases like this. I think it is an important thing to consider, in order to better win over the public to science.

A bit of must-read economics

2010-02-22T16:53:00.000-08:00

In the face of Obama's new healthcare initiative, which includes provisions to cap the increases in insurance costs, you can read here a nice description of the problems of fixing maximum prices. When the Government caps prices to help people, it is a policy which goes in the category of "really simple, intuitive, well-intentioned, and wrong."

More people need to understand the proper functioning of the free market. This is true of people on "Main Street" as well as those on Wall Street. I think I may be becoming more Libertarian in my old age. :)

Coin flips and names (Evil problems in probability continued)

2010-02-22T04:22:00.001-08:00

In my post about the girl-named-Florida problem, there is a factor in the analysis looking at the probability of having a girl named Florida given that you have two girls: P(F|2g).

This term is easily calculated as

which I used in the analysis.

Someone raised the question, "What would happen if (as we know) people don't tend to name two children the same (unless you're George Foreman)?" At first, this seems exactly like a coin flip problem: what is the probability of, in two coin flips, flipping heads on the first flip or flipping heads on the second but not both? It turns out that this is a different problem, and the result is surprising (at least to me). We have to be very careful what information we condition on, knowing that the English language is a little more fluid than we like when dealing with such problems. In the coin flip case we define

and it follows, given the probability of flipping heads is h,

which is just the standard result, subtracting off the possibility of having both heads. For h=0.5, this yields the standard result of P(h) = 0.5. As h gets close to 1, the probability of a heads goes way up, and thus the probability of both being heads goes way up. As a result, the probability of just having 1 heads goes to zero.

The situation with names is nearly the opposite: as the frequency of a name increases, the name is much more common. This makes it more and more likely that you will have someone with that name. The difference is in the conditioning information:

The analysis then goes:

which is exactly the same result as the case where one can name both of the children Florida! I was a little surprised by this result, but a quick simulation confirmed it as well.

Simulation

from pylab import *
from numpy import *

f=0.1
N=10000
r1=rand(N)
r2=rand(N)

N1=list(r1< f)
N2=list(r2< f)

case1=[n1 or n2 for n1,n2 in zip(N1,N2)]

print "Fraction allowing duplicate names: ",case1.count(True)/float(len(case1))
print "Theoretical Value: ",f+f-f**2

nn=[]
for n1,n2 in zip(N1,N2):
    if n1:
        nn.append(False)
    else:
        nn.append(n2)
        
N2=nn
case2=[n1 or n2 for n1,n2 in zip(N1,N2)]

print "Fraction not allowing duplicate names: ",case2.count(True)/float(len(case2))

Simulation Result

Fraction allowing duplicate names: 0.1853
Theoretical Value: 0.19
Fraction not allowing duplicate names: 0.1853

Magnetic therapy getting under my skin

2010-02-21T15:06:00.001-08:00

Introduction

Every year my family goes to the flower show in Providence. It's a nice time, seeing flowers in the middle of February, snacking on the pretzel and dip samples, and seeing all of the house and garden related vendors. It's tainted, however, by a particular vendor selling magnetic therapy items, such as bracelets, braces, and necklaces. The company is called Palmer's Global Magnetic Therapy, and I am bothered even writing their name here, giving them more exposure.

The Science

Their pamphlet has more science errors per square inch than any text I have ever read. For example,

Given that light is electromagnetic radiation, and I believe that light has been around a bit longer than people (even by creationist standards!), this definition is flat-out wrong. Saying that low-levels are "fought off" by the body, yet "higher levels are proving to cause gradual break down in health" is at best misleading: high levels of radiation, such as high-energy x-rays, break down organic molecules, but you aren't generally exposed to this in such high dosages. Either way, it is irrelevant to magnetic therapy where the magnets used are of such low intensity that no significant effect would be expected anyway.

On the medical side, this pamphlet is just as bad.

Let's take the last point first: "cancer cannot exist in a strong magnetic field". This is a true statement. What they left out is that, at that strength of magnetic field, non-cancerous cells also can't survive. It'd be like the statement: "cancer cells cannot exist is molten lava", which would be true...but useless and misleading.

The previous points, about the medical effectiveness of magnets, is also not correct. Although it seems to be challenging to have a blinded study of magnetic therapy, because people can easily test to see if the magnetics attract keys or other household items, careful studies have not found any effect of magnetic therapy. You can see some of them here, here, a nice wikipedia summary, and another very good summary of some other arguments against magnetic therapy.

I could go on and on with this, but I want to highlight a few things directly related to pseudo-scientific thinking. The following statement is indicative of the sort of thing, not limited just to magnetic therapy but to all forms of sham-medical treatments and much of pseudo-science as well.

Rephrased, a bit bluntly, this reads: "if you do our treatment for your ailment, and your ailment improves, then that is proof of the effectiveness of our treatment. if it doesn't improve, then you did something wrong, and it says nothing about our treatment". It's like the psychics who complain that the room isn't right, or their abilities are hampered by skeptical treatment, but otherwise they are perfect. Heads, I win. Tails, you lose. James Randi has pointed this out many times, with the people trying for his million dollar challenge. It is the type of thinking that protects you from ever being wrong, and thus places your statements outside of the realm of science. Unfortunately, it also generally means you're wrong, and are simply trying to avoid critique to keep the comfort of your misguided ideas.

Avoiding the FDA

In order to avoid the FDA, they have to put a disclaimer in, which reads:

However, does this disclaimer allow them to state the things above (about cancer), or these claims:

or these?

I'm no legal expert, but it seems to me that this is filled with medical claims, and simply stating "we are not making medical claims" should not be enough.

What to do?

I see these people every year, and every year I wonder what should I do. What is my moral obligation, what are my legal limits, what are my options? Sometimes I ignore them, but always feel bad afterward. I have a gut feeling that I have a responsibility to help save as many people from this scam as I can, especially since it is right in my backyard. I see people at the booth, and it drives me nuts. I try to educate my students, and anyone around me who will listen, but that doesn't feel like enough.

One suggestion that someone had was to set up a booth of my own, an anti-magenetic therapy booth. I'm not sure if this would either be allowed, or might be taken as libelous or something else that involves lawyers. There is the distinct possibility that it would simply make me look like a jerk, and work against the message that I would want to achieve.

A few years ago, I did approach them, and as gently as I could asked if they ever thought to consult a physicist concerning some of the claims in the pamphlet. It's a husband and wife team, and the wife was reasonably conversational. The husband was immediately aggressive and hostile. He questioned the need for such a thing, and when I pointed out a couple of straight-forward errors (not even the efficacy errors) he did not take it well. He even admitted to me, to my amazement, that he didn't care whether the claims were correct!

Another year I gave them a folder I'd prepared about magnetism, and some of the magnetic therapy studies. I even created an email address (brianthephysicist) for any questions they had...I never heard from them.

This year I submitted their website to the FDA website on "Reporting Unlawful Sales of Medical Products on the Internet". I have to admit that that felt good, but I doubt that in reality it will affect very much, if anything at all.

So I am still left with the questions: what should I do with this case? What is my moral obligation, what are my legal limits, what are my options?

Unfortunately, I don't really know.

Economics

2010-01-31T08:36:00.001-08:00

In a post about Ten Principles of Economics, Harvard Professor Greg Mankiw writes a little acrostic device about economics. In addition to things like "Everything has a cost. There is no free lunch. There is always a trade-off." for the "E" in economics, I found this one caught my eye: "One More. Rational people make decisions on the basis of the cost of one more unit (of consumption, of investment, of labor hour, etc.)."

My first thought was, is this really true? Perhaps a real economist will correct me, but I disagree with this statement. From my limited economics knowledge, a rational person makes a decision to maximize the net benefit resulting from that decision, given the information that the person has. This is maximizing the benefits minus the costs, or

Where B(q) is the benefit and C(q) is the cost, and q is a label for the different possible decisions, usually representing the quantity of a particular good that is purchased. To find the maximum (or minimum) we take the derivative and set it to zero:

The decision on the "basis of the cost of one more unit" is referring to dC(q)/dq, or the marginal cost. When the marginal cost equals the marginal benefit, then we are at an optimum (which could be a minimum of the net benefit!).

What I disagree with is that I don't think that people make a decision based on dC(q)/dq, but rather that they make decisions on B(q)-C(q). You might say, "But, hey, those are the same thing!". The distinction I think is found in the correspondence between a model and the real-world. Quantities like the cost of a good, or the benefit of the good, are directly observable and measurable. The marginals, or derivatives, of those same quantities are not directly observable but are inferred from the values of the non-marginal quantities at various values of q.

To make an analogy with physics, think of position and speed. Speed is change of position with time, or the "marginal position" if you will. You measure speed by taking different positions and different times of some object, and calculating speed. You don't measure speed directly. The analogy breaks a bit, because there are ways of inferring speed without position, using the doppler effect, which is how we can measure the speeds of very distant objects without knowing their position.

The question I have is, "Is there a similar way to directly measure the marginal cost, without first knowing the cost of the good?" I don't think that this is possible. First, I think it quite likely that there are cases where B(q)-C(q) is not differentiable, so it makes no sense to think of "just one more" but you can still maximize the quantity. The differentiation is a simplification, a model. Second, the equality of dC(q)/dq to dB(q)/dq occurs at both a minimum and a maximum, and needs to be confirmed if it is truly a maximum by going back to the values of B(q) and C(q). Thus knowledge of "one more" is incomplete. Finally, as stated above, I don't think that the marginals are directly observable, whereas the direct quantities are.

Hopefully an economist will comment and correct, or confirm, what I am saying!

Faith and Science

2010-01-31T07:18:00.001-08:00

I was listening to a very nice talk by Ken Miller, from Brown University. He's the Biology professor who testified in the Dover Evolution Trial. The reason that he is involved in cases involving the attack on evolution from the religious right is several-fold, including his knowledge of evolution (even though that is not his main area of expertise) and his widely-used textbook (which was the target of the warning labels in Georgia). Ken Miller keeps a page on evolution and his own webpage with many links, presentation slides, and talk videos. I think the most important reason for his involvement is that he is a self-acknowledged Christian (a Catholic, to be specific). Rather than inviting an expert like Richard Dawkins (who is decidedly anti-religious) to testify, it is much better to invite someone who claims there is no conflict between religion and science. Thus the case can't be cast as a battle between science and religion, and can be seen only as what is appropriate science education.

So in his talk, Ken Miller makes the point that science should inform faith and faith should inform science. He cites Paul Davies, a physicist who has an interest in theism, and whose article "Taking Science on Faith" takes the position that science itself is a faith-based activity. Ken Miller points out, and you can confirm in Paul Davies' article, that there are two tenets in science that are taken on faith:

the universe is ultimately knowable and understandable
knowledge is better than ignorance

At first I thought that one perhaps should call these axioms, more like mathematics, and not "faith" because something in me felt that these two ideas were different somehow than the belief in God. Then, I realized, that they are different fundamentally and faith, or even axioms, is entirely wrong.

The first idea, that the universe is knowable, needs to be a bit more specific: what does it mean to be knowable? Prior to 1900, it was believed that the pieces of a physical model, such as the force of gravity, or the electric and magnetic fields of Maxwell were "real": there was one-to-one correspondence between the model components and things in the real world. Thus, it was believed, that knowing the model you would know nature. After 1900, with the advent of quantum mechanics, physical models were evaluated based on their predictive value: those models that predicted well were good models. It was not believed that there was necessarily a correspondence between the model components and the real components in nature. Aspects of the model, such as the wave function, were not believed to be real but simply useful in making predictions. To know the world is to be able to predict what would happen.

Let's say we replace "understandable" with "predictable", a replacement which I think makes practical sense (how else would you determine that you understand something?), and is directly in line with modern physical thinking. Doing this, then tenet (1) ceases to be an axiom, or something we take on faith, but is observable. If the universe is unpredictable, then all attempts at making prediction will fail. This is not what we observe at all. Surely there are still things that are unpredictable, such as the simultaneous value of the position and momentum of the electron, or the positions of every molecule of air in this room, but even there we can make specific predictions about average quantities or the values of other variables of interest. Practically, the universe has demonstrated itself to be understandable, on the whole. This is not a matter of faith!

The second tenet (2) I would wager is too vague. What does "better" mean? Better for whom, or for what? Psychologically, one might argue something akin to "ignorance is bliss", and there might be something to that. If we define, however, "better" to be higher standard of living (longer, healthier, more free life) then knowledge can be argued to have a demonstrable benefit over ignorance. The results of science has doubled the life expectancy in the past 100 years, and has allowed us to live more free and healthy lives. The thousands of years of faith before that cannot say as much. As Carl Sagan says, science delivers the goods. Is there any convincing argument that ignorance is better, or that we really can't decide which is better? Is there a preferable definition of "better"?

A couple of interesting videos

2010-01-12T07:22:00.000-08:00

With the advent of computer technology, it can be challenging to distinguish fact from fiction. Both of the videos below are, in my opinion, strikingly real but are both fake (and funny!). Critical thinking skills are a must!

Creativity, Science, and the Brain

2010-01-12T06:08:00.000-08:00

In my post about Bruce Hood's interview I said there wasn't anything I disagreed with. After re-listening to it, I find my position is a bit more nuanced. I'd still like to look more closely at the experiments he cites to see if there is anything there that addresses my concerns, like the difference between believing in an external essence of an object versus experiencing the memories that an object elicits. In this post I want to address something that both Bruce and Tom dance around during the interview: the positive aspects of superstition.

Tom tries to tie Bruce down concerning the bad aspects of superstition, citing witch burning and crusades. Bruce refuses to acknowledge superstition as a bad thing, and simply states that superstitious thinking, combined with economic factors and political motivation, can lead to such bad consequences. He further states that intuitive thinking is essential for science. Science doesn't just creep forward in small steps, but is also driven by the intuitive leaps of the scientists. Our ability to see patterns leads us to the patterns we have accumulated in scientific knowledge, and this ability is a consequence of natural selection.

Bruce Hood further talks about unconscious reasoning, such as the dream of Friedrich Kekulé and the structure of benzene, and solving problems while you sleep or are taking a break. I myself have solved some problems this way, and many of the interesting physics problems that I have used in my teaching have come, seemingly randomly, while doing mundane things like raking leaves or taking a shower. Although he states that he is an atheist, and is a scientist, I don't think he goes far enough in supporting science. In this way, his omission leads to the sense that he is a bit too supportive of the poor thinking associated with superstition. He points out that much of it is not factually correct, but I think he misses a big point in his exposition (one that I am quite confident he'd agree with).

Carl Sagan put it this way:

At the heart of science is an essential balance between two seemingly contradictory attitudes—an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense.

It is this sentiment that is missing from the interview, and would have cleared up many of the questions. Yes, we are all programmed (via natural selection) to be superstitious, to see patterns that may or may not really exist, to attribute properties to objects that may or may not be real. Science works by starting with that, and skeptically testing every pattern to see if it is real. It is only the ones that can stand up to skeptical scrutiny that we can trust.

Thus, Bruce's "super-sense" is the starting point, the intuition which leads to "crazy" ideas, out-of-the-box solutions. Skepticism, open information, and honesty reduce the many possible ideas down to the ones that are true. In some way, this is like the process of natural selection: the "random" element in evolution (mutation, crossover, etc...) leads to variation, and natural selection works on that variation to produce the (far fewer) solutions that are optimal for the various ecological niches. In science, intuition gives us the variation, and skepticism and careful observation work on that variation to produce the (far fewer) solutions that are true.

Finally, in the fine words of Carl Sagan from his book "A Demon Haunted World" (the best science book for the public I have ever read!):

A physicist has an idea. The more he thinks it through, the more sense it seems to make. He consults the scientific literature. The more he reads, the more promising the idea becomes. Thus prepared, he goes to the laboratory and devises an experiment to test it. The experiment is painstaking. Many possibilities are checked. The accuracy of the measurement is refined, the error bars reduced. He lets the chips fall where they may. He is devoted only to what the experiment teaches. At the end of all this work, through careful experimentation, the idea is found to be worthless. So the physicist discards it, frees his mind from the clutter of error, and moves on to something else.

Believing the unbelieveable

2010-01-07T16:42:00.000-08:00

Have a listen to this excellent interview of neuroscientist Bruce Hood. I can't think of a single thing I disagreed with this guy on. I may have more specific to say later, and perhaps I will buy his book.

A teachable moment...lost

2010-01-07T11:47:00.001-08:00

So I just watched the Mythbusters episode where they recreate the bus jump from the movie Speed. They do two things: a miniature version and full-scale recreation. In their miniature version they scale down the bus by a factor of 12, very carefully building the model bus as closely as possible. Then they scale down the bridge by the same factor. They then point out that they can't scale down gravity without going to the moon. Technically, that would scale gravity by 1/6, not the required 1/12. You wouldn't even have to go nearly as far as the Moon to achieve this. Since force gravity decreases as the square of the distance away from the Earth (starting at 4000mi, the radius of the Earth), you would only have to go up this high:

compared to the 240,000 mi, that's a real bargain! But this is about 10,000 mi above the Earth, whereas the Hubble is less than 600 mi above the Earth, just to give some perspective.

So, without leaving the Earth, the NASA experts say that one can compensate by going faster. Mythbusters scrawls the analysis on the side of the buss and says "basically, what these hieroglyphics mean is to compensate for the physical impossibility of scaling gravity, the speed of our 1/12 scale bus has to be just over 20 miles per hour". What bothers me most about this is not that they don't really go through the analysis, but that they refer to basic math as hieroglyphics and they give no sense for why going a bit faster would compensate for gravity. I am going to include the full analysis here, but below I will also give a simpler explanation that they could have used, which only includes a small amount of math that would have easily fit on the side of the bus.

Analysis

Their analysis is equivalent to the following: the components of the speed off of a ramped angle are

and the x and y positions versus time are given by the standard motion equations

Here is the critical step. We solve for time, t, and get rid of it in the second equation. This way we have the shape of the entire trajectory in space, without any dependance on time.

or:

Now, what happens to this equation when we scale the distances down by a certain amount?

which is almost the same, except for one factor of gamma over the v² term. Thus, if we replace the speed with

the trajectory of the new version is identical to the old version. Now, remember, that this doesn't include time: the scaled version, going a faster, will reach the destination sooner.

A Clearer Way

I certainly wouldn't expect the television audience to follow that analysis, although I wouldn't mind them showing it anyway (but more explicitly). It's the sort of thing where many would ignore it, but the ones who could understand it would get more out of the show. So let's see if we can put it a bit more clearly. I'd start, first, by scaling down the sizes by a factor of 16 not 12. That way I can take the square root more easily. Then there'd be two more facts about gravity that I would mention

gravity doesn't affect motion horizontally
vertically, if I throw something up at three times the speed, it will go up nine times the height (the square of the speed increase)

Scaling down just the size, but not the speed, by a factor of 16 would decrease the time by the same factor of 16. If we scale the speed down by a factor of 4, then three things happen: the height of the trajectory reduces by 16 (item 2 above), the time of flight reduces by a factor of 4, and thus the horizontal distance covered (speed times time) is reduced by a factor of 4x4=16. Notice that in doing so, the object trajectory is scaled in both the vertical and horizontal directions by 16, which is the goal of the scaling.

I think that this is clearer than the way presented by Mythbusters, and should have been covered in this way, or some similar way. It could have have been a good teaching moment!

There once was a girl named Florida (a.k.a Evil problems in probability)

2010-01-05T08:22:00.000-08:00

In a previous post I described the Monty Hall problem, and noted that a simulation can often lead to clarity of thinking on tough probability problems. I take another example here, in two steps, and throw analysis and simulation at it and possibly a bit of intuition.

I was first introduced to this problem from Leonard Mlodinow's "The Drunkard's Walk: How Randomness Rules Our Lives" and immediately "fell for the trap". The problem exists in two parts, the first (easy) part followed by the second (hard) part. The easy part is as follows:

Say you know a family has two children, and further that at least one of them is a girl. What is the probability that they have two girls?

An easy way to do this is to list out the possibilities:

Boy-Girl
Girl-Boy
Girl-Girl

so you end up with 1 chance out of 3, or p=0.33. The hard part is the following:

Say you know a family has two children, and further that at least one of them is a girl named Florida. What is the probability that they have two girls?

At first I didn't think it would make any difference. How could knowing the name of the child change the chances for two girls? So I didn't believe the author (at first) that the chances were even, p=0.5, for the family to have two girls. Again we can list off the possibilities:

Boy-Girl (Florida)
Girl (Florida)-Boy
Girl (Not Florida)-Girl (Florida)
Girl (Florida)-Girl (Not Florida)
Girl (Florida)-Girl (Florida)

Since the last point is very rare (two girls named the same rare name?) we can ignore it, and we can also see that there are now two Girl-Girl possibilities with one named Florida, rather than just one, so it essentially gets two votes. Thus, we get p=0.5. Now, when I see something like this I worry. Yes, it's intuitive (once you see it) but I've seen slight-of-hand counting of the possibilities before. I don't trust it unless I can do two things:

write a simulation which reproduces it
show that a formal analysis works for the problem

As for the simulation (I post the code below) I get:

Probability for a girl to be named Florida:  0.01
Total number of families with two children:  1000000
999862 girls (0.499931 of children)
249745 both girls (0.249745)
750117 families with girls (0.750117)
249745 both girls (0.332941) given families with girls
10084 families with a girls named florida
4997 both girls (0.495537) given families with girl named florida

The formal analysis gets interesting, because I want to understand how the frequency, f, of the name affects the probability of having two girls. If it is a rare name (f ~ 0) then I should get p=0.5. For a common name (f ~ 1) then I should get p=1/3. Not that with f=1 then the word "name" is a little odd because all girls have it, so one might think of it as a label (like "has a nose"). First some notation:

Applying Bayes theorem to the easy problem, we get:

The hard problem is set up like:

It is clear that p({L1g}|2g)=1 whereas p({L1g},F|2g)=1 is not: given that we have 2 girls, we definitely have at least one girl, but we need not have at least one girl named Florida. Breaking the second term up we get

Now we have

It is easy to check that it has the right limits:

I'm not sure if there is a better way to address this problem, but the analysis and simulation agree, and further we have a very simple form for how the probability depends on the frequency of the known label (e.g. Florida).

Code for simulation

from pylab import *
from numpy import *

# 2 daughter problem

num_families=1000000
num_children_per_family=2

f_girls=0.5
f_florida=0.01
print "Probability for a girl to be named Florida: ",f_florida
print "Total number of families with two children: ",num_families

child_types=['boy','girl']
families=[ (child_types[randint(2)],child_types[randint(2)]) for x in range(num_families)]

names=[]
for f in families:
    
    if f[0]=='boy':
        name1='Bob'
    else:
        name1='Florida' if rand() < f_florida else 'Sarah'
        
    if f[1]=='boy':
        name2='Bob'
    else:
        name2='Florida' if rand()< f_florida and name1!='Florida' else 'Sarah'
        
    names.append( (name1,name2) )
    
# total fraction of children as girls
girls=0
children=0
for f in families:
    for c in f:
        children+=1
        if c=='girl':
            girls+=1
print "%d girls (%f of children)" % (girls,float(girls)/children)

# total fraction of families with both girls
both_girls=0
for f in families:
    if f[0]=='girl' and f[1]=='girl':
        both_girls+=1
print "%d both girls (%f)" % (both_girls,float(both_girls)/num_families)

# total fraction of families with both girls GIVEN that the family has a girl
families_with_girls=[]
for f in families:
    if f[0]=='girl' or f[1]=='girl':
        families_with_girls.append(f)
        
num_families_with_girls=len(families_with_girls)
print "%d families with girls (%f)" % (num_families_with_girls, 
                        float(num_families_with_girls)/num_families)

both_girls=0
for f in families_with_girls:
    if f[0]=='girl' and f[1]=='girl':
        both_girls+=1
print "%d both girls (%f) given families with girls" % (both_girls,
                            float(both_girls)/num_families_with_girls)


# total fraction of families with both girls GIVEN that the family has a girl named florida
families_with_florida=[]
for n,f in zip(names,families):
    if f[0]=='girl' and n[0]=='Florida' or f[1]=='girl' and n[1]=='Florida':
        families_with_florida.append(f)

num_families_with_florida=len(families_with_florida)
print "%d families with a girls named florida" % num_families_with_florida

both_girls=0
for f in families_with_florida:
    if f[0]=='girl' and f[1]=='girl':
        both_girls+=1
print "%d both girls (%f) given families with girl named florida" % (both_girls,
                            float(both_girls)/num_families_with_florida)

Weird associations and the brain

2010-01-05T06:56:00.000-08:00

You ever have deja vu? The brain associates many things together, and can often give you the visceral feeling that you've been there before. For several years I have had a very specific deja vu that I have finally tracked down. I found for some reason that when I watched the movie Unbreakable (great movie!) that later in the day I would recall a video game in my distant past called the Legend of Zelda, that I played on our Nintendo game machine. This happened a couple of times, so I felt there was some association that I couldn't quite pick up.

Then I noticed that each time, I was humming the theme song to Zelda during the day, and I finally figured out the association: the musical transitions in the themes are close enough that hearing one, I would continue with the other. The clips are below. If you listen to about 30 seconds of the Unbreakable music, you'll get the theme, and then go back to the Zelda clip. How random! But now I have the satisfaction of a puzzle solved!

Cool little fact of the day...

2010-01-04T07:17:00.000-08:00

Did you know that if you interleave the pages of two phone books, that it is nearly impossible to separate?

For those Mythbusters aficionados this won't be news, but since I don't watch TV I missed this one. I just heard about it yesterday, and didn't believe it. So I did a quick test myself and confirmed it! Very cool!

You can see what mythbusters does with it here (note: it involves tanks):

http://www.youtube.com/watch?v=hOt-D_ee-JE

Polar Bears, Data, Opinions, and Global Warming

2009-12-22T08:16:00.000-08:00

So I had a nice discussion with a student, who was confused after receiving some opposing viewpoints on Global Warming from different professors in a relatively short time period. In one of the statements, I had claimed that there were more polar bears now than there were 20-30 years ago. In another statement, another professor claimed that the polar bears were dying off due to arctic ice retreat due to global warming. This is actually a nice case of "follow the data", where the problem is defined in a relatively concrete way. Another example of this is the question "is it warmer now than 1000 years ago?". On the second question, www.realclimate.org would say "yes, it is warmer than 1000 years ago" and cite the proxy data, etc... www.climateaudit.org would say (I believe) "maybe, maybe not" and cite the issues with the analysis of the proxy data.

Now, back to the polar bears. From the polarbearsinternational it is confirmed that the population of polar bears from the 1960's was very low, in the few thousands, and in the early 2000s was up to between 22000-25000. These are also reflected in the usgs site on polar bears where you can actually get some of the data.

If you go to the polar bear specialist group which advises for the IPCC, you can find a table of the status of the polar bear in various regions. The problem with this table is that there is a column titled "Observed or predicted trend". Hello? Why would you mix observed trends and predicted trends in a table? Just show me the data. Anyway, there is a document here which has an explanation of the projections, and possibly some data, although I haven't read the 200 pages of the document to see if it is buried in the text (there is no figure with the data...just model predictions). I'd love to find a straightforward presentation of the estimates of the current numbers of polar bears, complete with error-bars to denote uncertainty.

It seems reasonable that with the decline of the arctic ice that the polar bear populations can be affected, some more than others, but the role of hunting (the regulation of which caused the surge in the bear numbers from the 1970s) still plays a role can is difficult to disentangle...I've seen unsubstantiated claims that the areas with the decrease are primarily hunting areas. I haven't confirmed this, but this could also be the fact that ice retreat will be more substantial in the more habitable areas, where there would be more people. Correlation does not equal cause and effect.

So, it is a fact that there are many more polar bears now than, say 30-40 years ago. It can also be true, although I have difficulty tracking the data down in a readable form, that arctic ice retreat could impact polar bear numbers adversely.

One question that I have now is, if it was warmer 1000 years ago, is there evidence that there was a significant retreat of the ice back then? If that is the case, then the polar bear scare is just that...a scare. Again, many of global warming consequences that are being reported are tied to the question of the size, extent, and effects of the Medieval Warming Period. That's why, in my opinion, that is the most important question of all.

Open Information, Reproducible Research, and Climategate

2009-12-15T07:42:00.001-08:00

David Donoho, the creator of Wavelab is featured in an article about reproducible research in the journal CISE (Computing in Science and Engineering). I am struck by the resonance of a couple quotes, as they apply to Climategate and Climate Modeling:

The scientific method's central motivation is the ubiquity of error--the awareness that mistakes and self-delusion can creep in absolutely anywhere and that the scientist's effort is primarily expended in recognizing and rooting out error.

[...]

In stark contrast to the sciences relying on deduction and empiricism, computational science is far less visibly concerned with the ubiquity of error. At conferences and in publications, it's now completely acceptable for a researcher to simply say "here is what I did, and here are my results." Presenters devote almost no time to explaining why the audience should believe that they found and corrected errors in their computations. The presenter's core isn't about the struggle to root out error--as it would be in mature fields--but is instead a sales pitch...

[...]

Many users of scientific computing aren't even trying to follow a systematic, rigorous discipline that would in principle allow others to verify the claims they make. How dare we imagine that computational science, as routinely practiced, is reliable!

On ClimateAudit, there is an older article (2005) about the Hockey Stick plot. Ross McKitrick makes the suggestion of an audit panel,

A group of experts fully independent of the IPCC should
be assembled immediately after the release of any future IPCC Reports to
prepare an audit report which will be released under the imprimatur of the IPCC itself. The audit will
identify the key studies on which the Report’s conclusions have been
based, and scrutinize those studies, with a view to verifying that, at a
minimum:

data are publicly available,

The statistical methods were fully described, correctly
implemented and the computer code is published

If the findings given maximum prominence are
at odds with other published evidence, good reason is provided in the
text as to why these findings have been given prominence.

Any competent scientist can assess these things. My strong
recommendation is that such a panel be
drawn from the ranks of competent mathematicians, statisticians,
physicists and computer scientists
outside the climatology profession, to prevent the conflict of
interest that arises because
climatologists face career repercussions from
publicly criticizing the IPCC. Also, participation should
exclude officials from environment ministries,
because of the conflict of interest entailed in the fact
that environment ministries are the main financial
beneficiaries of the promotion of global warming fears.

The second recommendation is for a "counter-weight panel", whose job would be to actively try to find holes in the analysis, assumptions, etc...

I'm not sure how I feel about the second one (I'll have to think about it), but the audit panel to me makes total sense. Why don't the scientific journals do this as a matter of policy?

Word of the Day: Micromort

2009-12-12T05:08:00.001-08:00

I'm not starting a new "word of the day" series, but I did learn this work today from the following video on risk analysis:

It's an entertaining introduction to risk analysis, and they use the word micromort, referring to a measurement of the quantity of an action which gives you a 1 in a million chance of dying. The website is www.understandinguncertainty.org.

Climate Change Denial is not the same as Evolution Denial

2009-12-10T17:00:00.000-08:00

Articles like this one and this one and others make the comparison between, what they call, global warming deniers and evolution deniers (aka Intelligent Design (ID) proponents), and even holocaust deniers. Personally, I find these comparisons misleading and dangerous. It is true that there are some who believe that climate is not changing at all, and that flies in the face of all of our knowledge of climate, weather, and the Earth system. Then there are those, like in climateaudit.org, that criticize the statistics of the data, and the possible false conclusions that can arise from that, and the lack of transparency on such an important topic. Lumping them in with the ID crowd is just ridiculous.

Why is the scientific consensus on Anthropomorphic Global Warming (AGW) different than the scientific consensus on Evolution? Let me list some of the ways:

Evolution has many independent, very different, lines of evidence (fossils, embryology, immunology, molecular biology, paleontology, etc...). AGW has at best 50-100 different data sets, from the dozen or so tree rings, to the dozen or so ice cores, satellite and surface temperature records. Much of our inference comes from computer simulations, that a very few completely understand. Much of global warming consensus comes from a small minority that are directly involved with the data or the simulations.
We can control aspects of evolution. With knowledge of DNA, we can make genetically modified foods, we can change the course of diseases, and breed bacteria to eat nylon. Our understanding of AGW is at such a low level that we can only possibly control the climate at the grossest level. Our lack of understanding of feedback loops prevents even the most basic possible control of the system.
Although evolution occurs on long time scales, we can see its action on the small scale. AGW also occurs on longish time scales, but there is no short-term equivalent. This adds to our level of control (with evolution), or lack of it with AGW.
Those that are denying evolution want to replace it with something that violates not just evolution, but all of physics, chemistry, astronomy...pretty much all of science. Although the extremists in the anti-global warming camp can seem pretty anti-science, they aren't trying to replace global warming with something that violates all of science (they still might be wrong!). There is also a much more nuanced camp that admits that the planet is warmer, but perhaps it is not as special as the AGW theory would suggest, and that draconian CO2 policies are unwarranted given the uncertainties. This puts it on a very different scale than the anti-evolution group.

It is dangerous to make the comparison. One is partly the demonizing of your opponent and, at the same time, angelizing (is that a word? :) ) ones own perspective: by saying that the AGW deniers are just like the evolution deniers, both makes the deniers seem unreasonable, but by association, implies that AGW is as solid as evolution. This latter claim, despite the claims of its proponents, is definitely hyperbole.

Climategate, oh my!

2009-12-09T02:54:00.000-08:00

I've been reading a lot about Climategate, and have a few comments now, and hopefully more to come. What sparked this current thread of thinking for me was this post over in the Statistical Modeling blog. He summarized the physicists perspective on the "settled science" in a nice way:

The evidence for anthropogenic (that is, human-caused) global warming is strong, comes from many sources, and has been subject to much scientific scrutiny. Plenty of data are freely available. The basic principles can be understood by just about anyone, and first- and second-order calculations can be perfomed by any physics grad student. Given these facts, questioning the occurrence of anthropogenic global warming seems crazy. (Predicting the details is much, much more complicated). And yet, I have seen discussions, articles, and blog posts from smart, educated people who seem to think that anthropogenic climate change is somehow called into question by the facts that (1) some scientists really, deeply believe that global warming skeptics are wrong in their analyses and should be shut out of the scientific discussion of global warming, and (2) one scientist may have fiddled with some of the numbers in making one of his plots. This is enough to make you skeptical of the whole scientific basis of global warming? Really?

I would love to go point by point in this quote and show the calculations, and I'd imagine that it would get stymied once I tried to put in the water vapor feedback. I need to read more about this, because from what I've read we don't understand the magnitude, or sign, of the cloud feedback and that it could easily wipe out any warming caused by CO₂ increases.

Some of the comments are very good too, like:

A. zarkov: I'm really disappointed to see you engage in the usual group think about global warming. Have you read the Wegman report? How come you don't refer people to ClimateAudit for the other side of the debate? Did you know that Michael Mann had to be forced by Congress to provide the data and codes behind the hockey stick calculation? ClimateAudit give you everything, the data and the R code they use. The other side stonewalls, and no wonder-- their results are a fraud.

The blog he refers to, climateaudit.org, is very interesting and is exactly the way the commenter says: they are all for open information. They post the data, the code, everything right up front and simply ask everyone else to do the same. Why this isn't required for all scientific publications, I don't know. Why it is not required for all high-stakes publications (ones that could result in very high-stakes policy) I don't know either. It's a travesty.

If everyone were as open about the data and the code, Climategate couldn't have happened.

One final comment on this thread:

Radford, Neal: Few people ever disputed that the current temperatures are higher than those of earlier times back to four hundred years ago. The big issue has always been whether the Medieval Warm Period (usually seen as occuring around a thousand years ago) was warmer than at present, since if it was, that makes the present warming seem not so unusal and perhaps due to natural causes.

This is my point too: if it was warmer 1000 years ago, then the hysterical language of the global warming media is completely unjustified.

From RealClimate.org:

Phil Jones in discussing the presentation of temperature reconstructions stated that “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) and from 1961 for Keith’s to hide the decline.” The paper in question is the Mann, Bradley and Hughes (1998) Nature paper on the original multiproxy temperature reconstruction, and the ‘trick’ is just to plot the instrumental records along with reconstruction so that the context of the recent warming is clear. Scientists often use the term “trick” to refer to a “a good way to deal with a problem”, rather than something that is “secret”, and so there is nothing problematic in this at all. As for the ‘decline’, it is well known that Keith Briffa’s maximum latewood tree ring density proxy diverges from the temperature records after 1960 (this is more commonly known as the “divergence problem”–see e.g. the recent discussion in this paper) and has been discussed in the literature since Briffa et al in Nature in 1998 (Nature, 391, 678-682). Those authors have always recommend not using the post 1960 part of their reconstruction, and so while ‘hiding’ is probably a poor choice of words (since it is ‘hidden’ in plain sight), not using the data in the plot is completely appropriate, as is further research to understand why this happens.

A must read is the article by David Holland,
which outlines the problems with the hockey-stick analysis. He explains the divergence problem, and the
history of all this far better than I can summarize here.

Universality of Religion

2009-12-06T06:32:00.000-08:00

On the Effect Measure blog, there is post about "Freethinker Sunday Sermonette: Dawkins on evolution and religion", with the following video:

I am struck by a few things.

First, in the blog post he mentions:
It assumes that all things we call religion or religious impulses are essentially the same or have some common core. This faces the philosophical problem of properties and propositions in general. For example, take the property of redness. Is there something that all objects we call red have in common? And if there is, is this the same kind of thing we call religious belief?

In fact there is something common to all things red: the wavelengths of light that are absorbed. I think what he is asking is whether we experience red in the same way as our friend. In fact, it is quite likely, and it is not a philosophical idea at all. It seems to me more and more that philosophy tries to handle questions that are out of reach for science (for the moment) but the solutions found in philosophy evaporate or are insubstantial once we really understand what is going on. Tom Mitchell has done some very interesting work with looking at fMRI data in his "Brains, Meaning, and Corpus Statistics" talk (talk slides on his home page).

In the work, he compares fMRI data from different individuals, and finds that he can correctly identify images and words from brain activity of one person, using the associations between the images and words derived from the brain activity of other people. This strongly suggests that the internal representations of words and concepts may be very similar between individuals. Not only that, but that we have the possibility of determining what those are and not just leave it up to philosophical ruminations.

Dawkins mentions belief in authorities as a psychological tendency that may lead to religious thinking under the right circumstances. I would further add the brain's tendency for seeing patterns where there are none as the other piece of the religious-thinking puzzle. It is evolutionary advantageous to see tigers where there are none as opposed to not seeing tigers where there are some. Not all errors are equally costly. Religious interpretation of experience seems to me to easily follow from these sorts of errors.

A great observation

2009-11-30T17:13:00.000-08:00

So this post from Laura Wattenberg's "Baby Name Wizard" blog has a wonderful observation:

Here's a little pet peeve of mine: nothing rhymes with orange. You've heard that before, right? Orange is famous for its rhymelessness. There's even a comic strip called "Rhymes with Orange." Fine then, let me ask you something. What the heck rhymes with purple?

If you stop and think about it, you'll find that English is jam-packed with rhymeless common words. What rhymes with empty, or olive, or silver, or circle? You can even find plenty of one-syllable words like wolf, bulb, and beige. Yet orange somehow became notorious for its rhymelessness, with the curious result that people now assume its status is unique.

I was directed to the quote by Andrew Gelman's Statistical Modeling blog, and he has other posts about names and sounds.

Information

2009-11-30T10:52:00.000-08:00

It all started with "information is beautiful", with this post about the 2012 non-issue, and then it went to this interesting figure which I am pondering...not sure if the labels are correct. Finally I was pointed to infochimps, a collection of data which I need to look at more closely.

We are in the information age, and I'd love the way the information in the first two links is portrayed, and I plan on playing in the infochimps site more.

Autotune, Science, and Creativity

2009-11-18T02:47:00.000-08:00

I was just introduced to a very creative project called the Symphony of Science. It uses a technology called Autotune, traditionally used to keep lousy pop singers in key. In real-time it adjusts the pitch of the singer, so what comes out of the speakers is the correct frequency. Technically, it's very challenging to modify the waveform consistently, and in real-time.

Anyway, this particular project takes famous scientists, and puts their speech to music. The music is catchy, and really captures well the philosophies of Carl Sagan and others. It just makes me realize how much I miss Carl Sagan, which then makes me miss Stephen Jay Gould and E.T. Jaynes.

Yet another reason to leave Iraq...dowsing for bombs

2009-11-14T04:13:00.000-08:00

So it seems as if the Iraqi police are dowsing for bombs and firearms, as covered in the New York Times and James Randi. They are doing this using a device they've purchased to the tune of $80 million, and it works no better using a coat hanger!

I think the best quote which summarizes the danger and the bad thinking is:

Major General Jehad al-Jabiri is head of the Ministry of the Interior’s General Directorate for Combating Explosives. “I don’t care about Sandia or the Department of Justice or any of them,” he says. “Whether it’s magic or scientific, what I care about is it detects bombs.”

Of course, if it hasn't been shown to detect bombs by science, the other option is irrelevant.

Netflix prize

2009-10-12T05:21:00.001-07:00

Fortune magazine had a recent article on the Netflix prize. A very interesting competition to increase their correct recommendation percentage by 10%. I was struck by a comment at the bottom by a reader of the article:

If it is true what the article says, that the BellKor team’s algorithms used information such as "genre" and "actors", then they plainly cheated!
This information was not available in the contest. The contest data had only 4 pieces of information: people ID, movie, date, and the rating values.
If BellKor managed to get extra information about the people and movies, it is hard to understand how NetFlix overlooked it. Therefore I'm quite sure that the article got the story wrong – it is too extreme to be believable. But if the article is right, then the winning team used crooked means to get the prize and its 'solution' does not worth much. Hope it is the first option…

I remember looking at the data, and if I recall correctly, I remember a script to add to the database from IMDB. I assume this was allowed, because otherwise there would have been no way to get 10%.

Disturbing video misusing Einstein's name

2009-10-10T19:01:00.001-07:00

I saw this video posted on facebook The link to one rebuttal, which links to the original, is here:

http://filipinofreethinkers.org/2009/10/08/does-god-exist-video-campaign-refuted/

I wrote as a comment to the person posting it:

Actually, this is not a true story, nor does it capture even in the slightest way the views of Einstein on religion (see http://www.einsteinandreligion.com/).

Although it is a cute video, there are logical flaws such as the fact that neither "hot" nor "cold" exists except as labels on "temperature", neither label with any special role.

I'm mostly disturbed by the fact that this Christian organization is trying to legitimize a flawed argument, by falsely attributing it to a very famous non-Christian, and nearly non-religious, scientist.

Recovery from Vision

2009-09-16T14:54:00.001-07:00

The following article talks about recovery of vision from people who were blind from birth. A couple of things really jumped out at me.

1.

S.K. could identify some shapes (triangles, squares, etc.) when they were side-by-side, but not when they overlapped. His brain was unable to distinguish the outlines of a whole shape; instead, he believed that each fragment of a shape was its own whole. For S.K. and other patients like him, "it seems like the world has been broken into many different pieces," says Sinha.

However, if a square or triangle was put into motion, S.K. (and the other two patients) could much more easily identify it. (With motion, their success rates improved from close to zero to around 75 percent.) Furthermore, motility of objects greatly influenced the patients' ability to recognize them in images.

This is very easily interpreted using the HTM framework. It's very interesting!

Probability Problems and Simulation

2009-09-16T05:36:00.000-07:00

There are a number of classic probability problems that challenge the intuition, both for students and for teachers. I have found that one way to overcome this intuition block is to write a quick simulation. A good example is the classic evil probability problem of the Monty Hall. The derivation of the solution is straightforward, but it is easy to convince yourself of the wrong answer. A quick simulation, like the one below, makes it clear: 1/3 of the time the host gets a choice with which door to open, and 2/3 of the time the host has no choice - with the other door having the prize. I find a numerical simulation helps to bolster my confidence in a mathematical analysis, especially when it is particularly unintuitive.

from random import randint
import random
turn=0
win=0
human=False

while turn<50:

   prize=randint(1,3)
   door_choices=[1,2,3]

   if human:
       your_first_answer=input('Which door %s? ' % str(door_choices))
   else:   # automatic
       your_first_answer=random.choice(door_choices)

   if prize==your_first_answer:  # happens 1/3 of the time
       door_choices.remove(your_first_answer)  # get the other two
       door_choices=sorted([your_first_answer,
                            random.choice(door_choices)])
   else:
       door_choices=sorted([prize,your_first_answer])

   if human:
       your_second_answer=input('Which door %s? ' % str(door_choices))
   else:   # automatic

       # always switch
        if door_choices[0]==your_first_answer:
           your_second_answer=door_choices[1]
       else:
           your_second_answer=door_choices[0]

   if your_second_answer==prize:
       print "You win!"
       win+=1
   else:
       print "You Lose!"

   turn+=1


print "Winning percentage: ",float(win)/turn*100

Frequentist thinking, or just bad math?

2009-09-09T18:25:00.000-07:00

In Steven Pinker's excellent book "How the Mind Works", he describes how people are bad at probability assessments, but are much better at frequency assessments (pg 348). It almost comes out and says that the brain is frequentist and not Bayesian, and it certainly implies it. He outlines how badly people do on the classic rare disease problem: "frequency of a disease is 0.01%, you take a test that is 99.99% accurate (false positives at 0.01%), you test positive. What is your chance of having the disease". People, even educated people (even in the medical fields) get this one wrong a lot.

Pinker contrasts this with "Think of 10,000 people, so we expect 1 to be infected and 9,999 to be not infected. You take the test, and the 1 person infected will almost certainly test positive, and we expect 1 person out of the 9,999 to test positive as well. We know that you tested positive, so what is your chance of having the disease?"

He claims that people are much better at getting the answer right. In my view, this is less about being good at calculating frequencies, and more about being bad at math. The second way of describing the problem pretty much sets up and carries out all of the "difficult" math, and then rounds so that all you have are small integer values. People do much better with that. If you want an example, not in probability, you can read my paper on "Teaching Energy Balance using Round Numbers: A Quantitative Approach to the Greenhouse Effect and Global Warming", which was motivated by the Weight Watchers system.

In the weight watchers system, counting calories (215+340+...) is replaced by dividing by 50 and rounding (4+7+...). Same result, but small numbers are easier to work with.

A nice series to look at

2009-09-02T09:36:00.000-07:00

Bill Harris has a nice blog entry about Bayesian versus Classical stats. I'd like to go through the rest of these posts, because I think there is some great stuff in there.

230 miles per gallon!

2009-08-12T09:52:00.000-07:00

So this story today about the new GM Volt to come out that supposedly gets 230 mpg. My first thought when reading it is that they are touting it as fossil fuel saver, and I'm skeptical. Essentially you are replacing one fossil fuel with another (whatever the electric company uses versus gasoline). There is no guarantee that the electric company will use less fossil fuel than you would use, say, per mile of driving. And there is no guarantee that the electric company will use *cleaner* fuel than gasoline. Plus, batteries tend to be notoriously difficult to dispose of, and are an environmental hazard themselves when thrown out.

One advantage to replacing mobile power (e.g. gasoline) with stationary power (e.g. electric company) is that one can replace the stationary power with nuclear, which you just can't do with cars.

It is claimed that it will be cheaper for end users, "In Detroit, where off-peak electricity rates are 5 cents a kilowatt hours, it will cost about 40 cents to recharge batteries overnight." One does have to factor in the maintenance costs, battery replacement, and battery disposal costs into the cost of owning this new car.

Now, I am not against this development, as such, but it is important (as always) to be aware of both the benefits and the costs of the new technology. It is far too easy to read one side of the equation, pat oneself on the back, while ignoring the hidden costs.

Free will

2009-07-30T05:06:00.001-07:00

After a discussion with a friend about Nostradamus, I realized that the existence of prophets conflicts with the idea of free will: if the future is written in such a way that we can make definite predictions years ahead of time, then the choices of people can mean nothing...they are thus not free. Perhaps this is true, but I find it interesting that Christianity (and probably other religions) has free will as a basic axiom, and yet prophets are a common and fill an important component of the faith!

neat way to introduce programming

2009-07-24T10:28:00.001-07:00

Just came upon this post which describes a nice analogy between programming and Dr Seuss' Sneetch star-on and star-off machines. A modified version might be useful even for older students.

another post here, although written in spanish, has a number of interesting LOGO (or python turtle) example exercises.

Silly challenge to silly statement

2009-07-24T07:18:00.001-07:00

There is a new Challenge to Global Warming Skeptics by the FiveThirtyEight statisticians, who did such a good job with the Obama-McCain forecasts. The challenge is summed up by:

"For each day that the high temperature in your hometown is at least 1 degree Fahrenheit above average, as listed by Weather Underground, you owe me $25. For each day that it is at least 1 degree Fahrenheit below average, I owe you $25."

He's trying to address recent statements by some conservatives, paraphrased as "It's cold this summer here in Minneapolis, so global warming must be wrong." That's a bit of a strawman, but from the Power Line blog post, there really is this sense of local vs global perspective.

Well, it's actually a pretty silly challenge to a pretty silly statement. No serious GW skeptic I've heard contests that their is warming on a global scale, but argues against the magnitude or, more commonly, the cause of the warming (human vs not). The statistical challenge here only addresses whether there is warming, and even there is rigged to win even if there were no real global warming, because of the urban heat island effect. Most of the thermometers started out in rural areas, or in fields outside of towns, and cities were built around them. Areas around pavement are warmer than the surrounding areas, so there would be a measured warming trend due to development, not due to atmospherics.

A better bet would involve predicting the global temperature for, say, 5 years from now (along with the uncertainty). Each side puts in their prediction, and pays $1 times the ratio of the posterior probabilities for the two models, P(M₁)/P(M₂). Would anyone take a bet like that?

A quick comment on error

2009-07-20T07:05:00.001-07:00

I read this article in the Week magazine, concerning the upcoming census. I plan to look at statistical sampling later, but I was struck by the following:

Because supporters and opponents tend to break down along partisan lines. Democrats favor sampling because the people who are traditionally hardest to count are the urban poor, minorities, and immigrants, all of whom tend to live in Democratic strongholds and vote Democratic. These groups are often undercounted because they move so frequently and do not trust government employees asking questions. Republicans, by contrast, stress that the Constitution specifies an “actual enumeration” of the population, not an estimate. They also argue that statistical sampling is inferior to counting. “Anyone familiar with public opinion polling can tell you that statistical sampling carries a margin of error,” Republican Reps. Darrell Issa and Patrick McHenry recently wrote. “And error is the enemy of a full and accurate census.”

The notion that a national count is completely error free is ridiculous. I think everyone would agree that if you do a count, that you will not get everyone. It is known that mistakes are made, omissions occur, and that some people actively avoid the census. Because the census avoidance is not random, the omissions are biased in some way. One can argue in which ways the bias points, but the bias is there.

So what is the best plan of action in this case? You want to make an estimate of the number of people in the country. "Estimate" is the correct word, even for an enumeration, given the fact that the enumeration is known to be incomplete. The best thing to do, then, is to have a public and open statistical model of the process of sampling, with independent ways to confirm the validity of the model. If the model is simple, and open, it would be difficult to argue against. Without this approach, a "strict enumeration" is really an unstated statistical model where the assumptions are very difficult to see.

Laplace and the Divine

2009-07-19T05:04:00.001-07:00

In a previous post I used the word "God" in quotes, when referring to Laplace's view of determinism. This was done because Laplace himself did not believe in God, and I used the term as a convenience to represent a hypothetical all-knowing being. The clearest view of Laplace's perspective comes from an interaction with Napoleon. After reading Laplace's Mécanique céleste, Napoleon asked him about the lack of the reference to God anywhere in the work. Laplace responded that he had no need for that hypothesis.

In a strict way, this is an agnostic perspective. The description of the universe, as described by Laplace, does not need to use the concept of God in any way. This does not disprove the existence of God, or even deny God's existence. It merely states that the concept of God is not needed. This is the pure vision of science, and why science does not necessarily conflict with religion. However, there could be certain claims from specific religions that conflict with science. The 6000 year old Earth, part of some fundamentalist Christian beliefs, is one example. The God as the mystery in the Universe is not something that can conflict with science.

Misunderstanding Laplace

2009-07-18T17:58:00.001-07:00

I finished Leonard Mlodinow's "The Drunkard's Walk: How Randomness Rules Our Lives" this past week, and have a couple of thoughts related to it.

In Chapter 10 he quotes Laplace:

"We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes."

and Mlodinow states that this is an expression of determinism. He then further states

But for Laplace's dream to hold true, several conditions must be met. First, the laws of nature must dictate a definite future, and we must know those laws. Second, we must have access to data that completely describe the system of interest, allowing no unforeseen influences. Finally, we must have sufficient intelligence or computing power to be able to decide what, given the data about the present, the laws say the future will hold.

He then criticizes it with the following three problems:

society is not governed (as far as we know) by definite and fundamental laws in the way physics is
like Lorenz, we cannot obtain the precise data necessary for making predictions
human affairs are so complex that it is doubtful we'd be able to make the calculations anyway

He concludes "as a result, determinism is a poor model for the human experience." His point seems to be, in some ways, obvious and in other ways irrelevant.

Laplace was simply saying that "God" would not find anything random, because of complete knowledge. The connection between knowledge and inference, which probability theory affords, was worked out by Laplace in great detail and it known to use today as Bayesian inference. The structure of Bayesian inference describes randomness simply as the product of our ignorance of the model, the parameters, the initial conditions, the measurement details, etc... Laplace was simply saying that with perfect knowledge, there is no randomness. E.T. Jaynes would describe the "random process" as a mind-projection fallacy: you have ignorance of the system, so you attribute its unpredictable behavior as a product of the system itself. A rolled die is following Newton's Laws, deterministically, and detailed knowledge of the die and the roll and the surface should allow you to predict 100% of the time what it will do. We lack that knowledge, thus the behavior becomes unpredictable. We often then attribute that unpredictable behavior as a "random die", as if it were the die that contains the randomness and not our own ignorance.

Bringing in Lorenz, and chaos theory, is irrelevant here. Lorenz's systems were completely deterministic, and it is theoretically possible for a being to know the state of the system out to a sufficient number of decimal places to provide any particularly set level of uncertainty in the system. With the quantization of states, it then becomes possible to know *exactly* what state something is in. Of course, quantum mechanics is a two-edged sword in this example: it solves the chaos problem, but adds an inherent, physical, randomness to the system which is very peculiar.

The problem with Mlodinow, it seems, is that he hold human activity to be a bit too special. We are, after all, made up of atoms and would thus be governed by the laws of physics. Certainly it would be too complex to handle, for us, but Laplace was not talking about us in his quote, or at least not us right now or in the near future.

Homeopathic "Medicine"

2009-07-10T03:17:00.000-07:00

Homeopathic medicine "is a form of alternative medicine, first expounded by German physician Samuel Hahnemann in 1796, that treats patients with heavily diluted preparations which are thought to cause effects similar to the symptoms presented." (http://en.wikipedia.org/wiki/Homeopathy). I saw the mock video below on the skeptics blog, http://skepticblog.org/, and thought it was so amusing I had to post it here. I've known people who swear by this stuff, which is unfortunate. Treatments like these, that don't work, are dangerous and can actually kill people by diverting them from legitimate treatment. A good analysis of this is at http://www.csicop.org/si/9709/park.html.

The video, however, is quite amusing.

"Erroneous" Probabilistic Reasoning

2009-07-08T15:10:00.000-07:00

I've been reading Leonard Mlodinow's "The Drunkard's Walk: How Randomness Rules Our Lives", and he describes a set of experiments which I had heard of before but never gave too much thought to. The experiments deal with people making probability assessments about a series of statements. The experiments were done by Daniel Kahneman and Amos Tversky[cite here]. It starts with a description:

Imagine a woman named Linda, thirty-two years old, single, out-spoken, and very bright. In college she majored in philosophy. While a student she was deeply concerned with discrimination and social justice and participated in antinuclear demonstrations.

They then ask for a ranking of most (1) to least (8) probable for a number of statements. The interesting three statements are:

Linda is active in the feminist movement: 2.1
Linda is a bank teller and is active in the feminist movement: 4.1
Linda is a bank teller: 6.2

This is then used to say that people do not figure probabilities correctly because "the probability that two events will both occur can never be greater than the probability that each will occur individually" (italics in original).

The book reports that "even highly trained doctors make this error", with the following example.

They presented a group of internists with a serious medical problem: a pulmonary embolism (a blood clot in the lung). If you have that ailment, you might display one or more of a set of symptoms. Some of those symptoms, such as partial paralysis, are uncommon; others, such as shortness of breath, are probable. Which is more likely: that the victim of an embolism will experience partial paralysis or that the victim will experience both partial paralysis and shortness of breath? Kahneman and Tversky found that 91 percent of the doctors believed a clot was less likely to cause just a rare symptom than it was to cause a combination of the rare symptom and a common one. (In the doctor's defense, patients don't walk into their offices and say things like "I have a blood clot in my lungs. Guess my symptoms."

Now, I haven't read past this point, or the original study, so take what I say here with a grain of salt. I wanted to put down my thoughts on these observations before going on to read the study's conclusions. Perhaps what I say now will be inconsistent with other aspects of the studies, or further data.

I do not think that one should conclude poor reasoning in these examples.

I believe there are two things going on here. One is a property of the English language, and the other is a property of human reasoning. In English, if I were to say "Do you want steak for dinner, or steak and potatoes?" one would immediately parse this as choice between

steak with no potatoes
steak with potatoes

Although strict logic would have it otherwise, it is common in English to have the implied negative when given a choice like this. If we interpret the doctor's choice, we have:

clot with paralysis and shortness of breath
clot with paralysis and no shortness of breath

the second one is much less likely, because it would be odd to have a clot and not have a very common symptom associated with it. It is less clear in Linda's case, but I think the same reasoning applies there. What is interesting is that the error is not seen in ranking statements which have nothing to do with the given knowledge about Linda, such as:

Linda owns an IHOP franchise
Linda had a sex-change and is now Larry
Linda had a sex-change and is now Larry and owns an IHOP franchise

There might be something to being completely unrelated that changes the interpretation of the English sentence, and makes it a bit more formal, closer to the mathematical reasoning. I am not sure what types of statements would do this, but it is a bit challenging to disentangle subtle language interpretations I think.

When reading these experiments, I recalled a description from E.T. Jaynes about people receiving the same new information, but updating their knowledge in a diverging way, due to differences in their prior information. I think something like that could be going on here. What I mean is, when doctors are asked: "Which is more likely: that the victim of an embolism will experience partial paralysis or that the victim will experience both partial paralysis and shortness of breath?" it is interpreted as:

someone is claiming that the patient has an embolism
the patient is claiming, or someone has measured, that she has partial paralysis
the patient is claiming, or someone has measured, that she has shortness of breath

I don't believe the doctors are separating the analysis of the claim of the clot, which is given information, from the other claims. As Mlodinow admits, the situation where one knows the diagnosis is practically never encountered, so the doctors are really assessing the truthfulness of the existence of the clot. Because of this, the implied negative in (2) above (i.e. paralysis with no shortness of breath) is even stronger.

Another way of looking at it is to include the knowledge of the method of reporting. Someone who is reporting information about an ailment will report all of the information accessible to them. By reporting only the paralysis, there are two possibilities concerning the person measuring the symptoms of the patient:

they had the means to measure shortness breath in the patient, but there was none
they did not have the means to measure shortness of breath

In the first case, the doctor's probability assessment is absolutely correct: both symptoms together are more likely than just one. In the second case, the doctors are also correct: one of the sets of diagnostic results (i.e. just paralysis) is less dependable than the other set (i.e. both symptoms), thus the second one is more likely to indicate a clot or is consistent with the known clot.

It isn't that the doctors are reasoning incorrectly. They are including more information, and doing a more sophisticated inference than the strict, formal, minimalistic interpretation of the statements would lead one to do.

This analysis works well for other examples stated in the book, like "Is it more probable that the president will increase federal aid to education or that he or she will increase federal aid to education with function freed by cutting other aid to states?".

Now I have to continue reading the book, and track down the study, to see if any of these thoughts pan out.

A Little Geometry

2009-07-07T18:13:00.000-07:00

I've just finished the book "Euclid's Window" by Leonard Mlodinow, and really enjoyed it. The book describe the history of geometry from Euclid, Descartes, Gauss, and Einsten. During his coverage of Euclid he presents a simple proof of the Pythagorean Theorem that really resonated with me. I don't recall ever seeing a proof of it, or at least no memorable proof. This one uses a minimum of jargon and formality...you just draw the picture, discuss it for a bit, and you see it!

You start with a right triangle, like:

and you make two constructions, from a square with sides a+b. The first construction looks like:

which, by eye, you can see that the total area of the square is the area of 4 triangles (just like our original) plus the area of the inner square, which is c*c (which reminds me that I have to figure out how to do superscripts and subscripts in this blog. :) )

The second construction is nearly the same as the first, and looks like:

which, again by eye (with a little shading to make it a bit more obvious), the total area of the square is the area of 4 triangles (just like our original) plus the area of the two inner squares, which are a*a and b*b. Therefore:

a*a+b*b=c*c

for any triangle for which you can make this construction, which are right triangles.

Really neat!

Beginnings

2009-07-07T16:01:00.000-07:00

Although I seem to have missed the big blog burst, I am starting one now to include my musings on various topics of my interest, from statistics and probability to physics and history.

Professor Brian Blais' Blog

Moving....

Mystery, Knowledge, Science and Television

Climate and the Moon

Knowledge and Belief

Science and Attitudes Toward Criticism

Reaping the benefits of science while hostile to science

"Frivolous" research in science

Energy Bracelet Experience

Religion, Scripture, and the Source of Morality

Wonders in Science

A Reasonable Perspective on Global Warming

Does Watson Think?

Creationism and Strawmen

Wonders in Science

20 Years of Being an Atheist Ends Today

The Role of Humanity into the Future

Bill O'Reilly, Tides, and the God of the Gaps

Why I Can't Support the Darwin Day Resolution

The world is flat!

A modest proposal about uncertainty

The Economics of Religion: More good than harm?

Rounds in Australian Open

Round 2

Round 3 - Given Jan 20, 2011

Predictions for the Australian Open

Religion, Science, and Humility

Francis Collins, Science and Religion: How Religion Halts Science

A Moral Argument for God

Moral Law and the Argument for God

An Analogy

Are Science and Religion Incompatible?

Science is in conflict with some religions

Science is not in conflict with some other religions...but with a caveat

But shouldn't science stay out of religious issues? Don't they speak about different things?

Religious vs Scientific Thinking

Is -x^2 positive or negative?

Glenn Beck on Science

A walk down memory lane

Power UnBalance

Multiple Model Comparisons Revisited

Introduction

﻿The Octopus, Again

God and Hawking

Why pseudoscientists like the chi-square test (and why it shouldn't be taught)

Intuition and Chi-square: The Three-sided coin

The &psi-measure and log-likelihood

An almost equivalent problem

Still taught?

Orthodox Statistics Conducive to Pseudo-Science

Astrology

Subset of the Data

A different measure

The Non-Psychic Octopus

Introduction

Bayesian Analysis Against Random

More to the Story

A new and content-free model

Pascal's Global Warming

Religion and Scientists

Spirituality

Religious Scientists

One last TV post, about Battlestar Galactica

Battlestar Galactica, Lost, and Babylon 5: To Plan or not to Plan

Lord of the Rings

Nice talk about science and vaccination

The Not-so-Hidden Flaw in this Climate Argument

Introduction

Conduction, Convection, Radiation, Oh My!

Scientific-sounding Junk

A bit of must-read economics

Coin flips and names (Evil problems in probability continued)

Simulation

Simulation Result

Magnetic therapy getting under my skin

Introduction

The Science

Avoiding the FDA

What to do?

Economics

The Octopus, Again