In terms of 'usefulness' of psychadelics with things such as meditation, I would say that they do have some, but that far too little is being said by just that.
I think it was Timothy Leary (but maybe Watts or Huxley) that very wisely suggested that psychadelics may, in a scientific way of putting it, 'unlock' or blaze new neural pathways in the brain that have been left all but dormant after years of relatively conditioned living. In my case, it seems that this may hold some water...but it is, nonetheless, completely theoretical.
The fact is, many people that may fancy themselves very 'awakened' or what have you may have some very nasty experiences on these drugs and sometimes come out with nothing more than a pretty traumatic psychological incident...something that nobody needs to carry around.
On yet another perspective, most of the other folks I took mushrooms with during the incident mentioned in the previous posting enjoyed the experience altogether (minus my freaking them out ). While I was 'tweaking' on the other floor of the apartment, they were tantalized by the hallucinations and strange feelings. When I spoke to them long afterwards, they couldn't relate to me anything in the remotest way spiritual resulting from the experience. That is, as far as they were concerned.
Psychadelics are a very personal type of drug that, in my opinion, have somewhat unpredictable effects depending on the user: the users past experiences, the users general attitude at the time, the users general mindset, religious beliefs, and the situation of family, friends, etc.
Maybe they are useful, maybe not. I do think that Leary's idea might make some sense and, of course, I can't say that my experience doesn't seem to show something similar.
At any rate, I think Alan Watts (who wrote The Joyous Cosmology on the topic of psychadelics and mystical experience) hit the nail on the head when he said, speaking in terms of LSD, in this case:
"My retrospective attitude to LSD is that when one has received the message, one hangs up the phone. I think I have learned from it as much as I can, and, for my own sake, would not be sorry if I could never use it again. But it is not, I believe, generally known that very many of those who had constructive experiences with LSD, or other psychedelics, have turned from drugs to spiritual disciplines—abandoning their water-wings and learning to swim. Without the catalytic experience of the drug they might never have come to this point, and thus my feeling about psychedelic chemicals, as about most other drugs (despite the vague sense of the word), is that they should serve as medicine rather than diet."
