Rationality training should not be based on disciplines full of confusion. Philosophy is practically defined as a set of questions (so far) so confusing that they cannot be properly addressed by some branch of science. Economics is closely tied to politics and has (because of many practical reasons) a very limited possibility for empirical testing. They may be good disciplines to work on for an already advanced rationalist - and there are aspects of rationality which one can't illustrate well on examples from physics - but one has better to master basic rationality before one comes to studying philosophy and economics.

Ah yes, that's definitely true. I was really only pointing out the fields that could provide the best training for those who were LessWrong users. Which doesn't take that much - it's a lot easier to detect the bullshit in philosophy/economics than to learn the rationality inherent within them.

Is there an evidence for other fields of study, namely for philosophy and economics?

Perhaps not. All I know is that a substantial number of rationalists end up pursuing examples from philosophy and economics

But in general, the best training for rationalists cannot come out of most college programs (outside of Caltech/MIT).