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
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.
- 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.