Andrew Sabl adds his voice to these dissents:

Give mushrooms to a bunch of hippies and they’ll gain a new appreciation for yoga; give them to a heterodox Catholic and he’ll ponder the Incarnation. Give them to me and I might start to (wrongly) believe that I can understand complex mathematical proofs or conceive (wrongly) that I remember my once-adequate ancient Greek—which once gave me the very fulfilling experience of being able to read easy bits of Plato without a dictionary. But in none of these cases is there any reason to think that the drug-takers have come to know anything that’s actually true. And I would have thought that this would be relevant.

Drum introduces romance into the debate. I'm working on a follow-up post.