Traditional Rationality doesn’t have the ideal that thinking is an exact art in which there is only one correct probability estimate given the evidence.
The ideal process applies Bayes’ rule to the evidence and the prior probabilities to get the (posterior) probability estimate. Since there is no law saying what prior probabilities to assume, thinking is not an exact art in the sense used here. You might have meant that there is value in Traditional Rationality having this ideal even if we know it to be false, but in that case I don’t understand your point.
The prior isn’t trivial because one can model theism as doing Bayesian inference on a contrived prior. Take some reasonable prior, reassign the probabilities of all universes in which Christianity is false or meaningless to zero, scale to get the total probability back to 1, and use the result as the prior probability input to Bayes’ rule. This gives rationalist Christianity.
This contrived prior was selected with knowledge that Christianity exists, and newborns don’t know that, so it isn’t a prior that describes the inborn suppositions of any real person. But this crazy thing exists mathematically so we can’t say accuse Christianity or other theists of being irrational in the sense of failing to apply Bayes’ rule to some prior just because they are Christian.
Today, one of the chief pieces of advice I give to aspiring young rationalists is “Do not attempt long chains of reasoning or complicated plans.”
I agree with this, but it was amusing to find this sentence in your 2000+ page (according to Kindle) “Rationality” book.
In response to:
The ideal process applies Bayes’ rule to the evidence and the prior probabilities to get the (posterior) probability estimate. Since there is no law saying what prior probabilities to assume, thinking is not an exact art in the sense used here. You might have meant that there is value in Traditional Rationality having this ideal even if we know it to be false, but in that case I don’t understand your point.
The prior isn’t trivial because one can model theism as doing Bayesian inference on a contrived prior. Take some reasonable prior, reassign the probabilities of all universes in which Christianity is false or meaningless to zero, scale to get the total probability back to 1, and use the result as the prior probability input to Bayes’ rule. This gives rationalist Christianity.
This contrived prior was selected with knowledge that Christianity exists, and newborns don’t know that, so it isn’t a prior that describes the inborn suppositions of any real person. But this crazy thing exists mathematically so we can’t say accuse Christianity or other theists of being irrational in the sense of failing to apply Bayes’ rule to some prior just because they are Christian.
I agree with this, but it was amusing to find this sentence in your 2000+ page (according to Kindle) “Rationality” book.