Yvain:

You've hit on something that I have long felt should be more directly addressed here/at OB. Full disclosure is that I have already written a lot about this myself and am cleaning up some "posts" and chipping away here to get the karma to post them.

It's tough to talk about meditation-based rationality because (a) the long history of truly disciplined mental practice comes out of a religious context that is, as you note, comically bogged down in superstitious metaphysics, (b) it is a more-or-less strictly internal process that is very hard to articulate (c) has become a kind of catch-all category for sloppy new-age thinking about a great number of things (wrongheaded, pop quantum theory, anyone?)

Nevertheless, as Yvain notes, there is indeed a HUGE body of practice and tried-and-true advice, complete with levels of mastery and, if you have been lucky enough to know some the masters, that palpable awesomeness Eliezer speaks of. I'm sure all of this sounds pretty slippery and poppish, but it doesn't have to be. One thing I would like to help get going here is a rigorous discussion, for my benefit and everyone's, about how we can apply the science of cognition to the practice of meditation and vice versa.