But why should we assume that lawyes' abilities will not rise as well?
I expect that the sorts of people who become lawyers today are already better acquainted with critical thinking techniques than the sorts of people who become jurors. Also, I expect an across-the-board training curriculum for subject X to have more of an impact on people who know little about X than it does on people who know a lot about X -- that is, I expect it to raise the floor more than the ceiling.
Therefore, I expect an across-the-board critical thinking curriculum to reduce the difference between a typical lawyer's abilities and a typical juror's abilities in areas related to critical thinking. If you raise the floor more than the ceiling, average height differences tend to decrease.
But surely lawyers will play to their audience, and learn to present whatever fallacies the jurors will be susceptible to.
Sure, but again, I don't expect them to be able to improve enough to maintain the same proportional superiority to jurors, for essentially the same reason that ten years of additional life experience sharply reduces the cognitive advantages that a typical 25-year-old has over a typical 15-year-old.
Also, if juries were sufficiently trained in critical thinking, then lawyers who actually had the facts on their side would eventually find that presenting the actual facts, and pointing out the fallacies in their opponents' arguments, would be a viable strategy. (Right now, I doubt that it is for most juries.) In other words, the more effective the jury is at distinguishing truth from falsehood, the more of an advantage the truth is to a lawyer.
Why do you think it wouldn't work?
Sorry; I thought my analogy was clearer than it was. I expect it not to work because there just isn't enough leverage between the place we'd be exerting the effort (classrooms) and the place where we'd be expecting the results (courtroom), much as with grade school calisthenics and soldiers. That is, I don't actually anticipate the kind of increase in critical thinking skill among jurors I'm discussing here based on the kind of curriculum I'm discussing here, any more than I expect a typical thirty-year-old to know how to factor a polynomial expression or diagram a sentence.
I'd love to be wrong, though.
I'm interested in how courts and juries might use rational techniques to arrive at correct decisions on guilt.
In a complex case, it would seem to sensible to assess each component of the prosecution and defence case, and estimate the relative likelihood. If the prosecution case is (say) 100 times more likely than the defence case, then you can say the defendant is guilty beyond reasonable doubt.
I never heard of this being done though. I recently made an analysis of the Massei report into the Amanda Knox case. It looked like this ( see http://massei-report-analysis.wikispaces.com/ for the entire analysis and some insight into the numbers below ).
This is perhaps a bit vague. It's not a great example, because in the end I didn't find any credible prosecution evidence. It's not entirely clear what the "probability" numbers here actually are, and whether two columns are needed. But hopefully it shows that the Massei's account of the murder is quite improbable, and there is considerable doubt.
I'm interested in possibly devising a more complete framework for how such an assessment should be done, the pitfalls that need to be guarded against (how uncertain are the probability estimates?), and even views as to how "reasonable doubt" should be quantified.
Perhaps readers would like to make an assessment of other interesting cases, to explore the issues.
Or how would you approach this problem?