Let me take a step back here, because despite the fact that it sounds like we’re arguing, I find myself in total agreement with other comments of yours in this thread, in particular your description of how trials should work; I could scarcely have said it better myself.
Here’s what I claim: the rules of evidence constitute crude attempts to impose some degree of rationality on jurors and prosecutors who are otherwise not particularly inclined to be rational. These hacks are not always successful, and occasionally even backfire; and they would not be necessary or useful for Bayesian juries who could be counted on to evaluate evidence properly. However, removing such rules without improving the rationality of jurors would be a disaster.
(Let’s not forget, after all, that there were people here on LW who reacted with indignation at my dismissal of certain discredited evidence in the Knox case, protesting that legal rules of admissibility don’t apply to Bayesian calculations—as if I had been trying to pass off some kind of legal loophole as a Bayesian argument. Such people were apparently taking it for granted that this evidence was significant, which suggests to me that it is very difficult for people—even aspiring rationalists—to discount information they come across. This provides support for the necessity of rules that exclude certain kinds of information from courtrooms, given the population currently doing the judging.)
Okay, then I think we’re in agreement. I guess I had interpreted your earlier comment as a much stronger claim about the mapping between pure Bayesianism and existing legal systems, but I definitely agree with what you’ve said here. I would just note that it would probably be more accurate to say that the rules of evidence are hacks to approximate Bayes and correct for predictable cognitive biases, though perhaps in this context those aren’t quite separate categories.
I think that is an incomplete description of the justification of the rules of evidence—some of these rules are also introduced to discourage particular abuses of the system, such as unreasonable searches. Otherwise, agreed.
Let me take a step back here, because despite the fact that it sounds like we’re arguing, I find myself in total agreement with other comments of yours in this thread, in particular your description of how trials should work; I could scarcely have said it better myself.
Here’s what I claim: the rules of evidence constitute crude attempts to impose some degree of rationality on jurors and prosecutors who are otherwise not particularly inclined to be rational. These hacks are not always successful, and occasionally even backfire; and they would not be necessary or useful for Bayesian juries who could be counted on to evaluate evidence properly. However, removing such rules without improving the rationality of jurors would be a disaster.
(Let’s not forget, after all, that there were people here on LW who reacted with indignation at my dismissal of certain discredited evidence in the Knox case, protesting that legal rules of admissibility don’t apply to Bayesian calculations—as if I had been trying to pass off some kind of legal loophole as a Bayesian argument. Such people were apparently taking it for granted that this evidence was significant, which suggests to me that it is very difficult for people—even aspiring rationalists—to discount information they come across. This provides support for the necessity of rules that exclude certain kinds of information from courtrooms, given the population currently doing the judging.)
Okay, then I think we’re in agreement. I guess I had interpreted your earlier comment as a much stronger claim about the mapping between pure Bayesianism and existing legal systems, but I definitely agree with what you’ve said here. I would just note that it would probably be more accurate to say that the rules of evidence are hacks to approximate Bayes and correct for predictable cognitive biases, though perhaps in this context those aren’t quite separate categories.
I think that is an incomplete description of the justification of the rules of evidence—some of these rules are also introduced to discourage particular abuses of the system, such as unreasonable searches. Otherwise, agreed.