On Psilocybin:
Anecdotally, mushrooms are about as likely to disrupt existing patterns of magical thinking as they are to inspire new ones.
The experience of being absolutely certain that your friend in the other room can read your thoughts and the discovery when you come down that no, he was thinking something completely different than you thought is sobering.
The experience of realizing how large the world is, how many people are in it talking at all times, can undermine conspiracy theories that depend on a tiny cabal of people keeping a secret while using hundreds of workers to accomplish a task, like faking the moon landing.
The "inner truths of the universe" that people feel are exposed by mushrooms are so abstract that they're not likely to actually interfere with rational thought. Mushrooms induce a metaphoric mode of thought. Realistically, we are all connected, by atmosphere, ecosphere, society and economy.
It's true that we don't have a solid scientific understanding of the long term implications, but we have a pretty solid population of people who've done mushrooms casually. It's not an uncommon drug.
All that aside, we have an FDA review process so that we can evaluate the safety of a drug. No drug is ever evaluated to see if it has a long-term negative societal effect because of how it alters your world-view. The effects that Depakote, Prozac and Ambien have had on society are likely significant and are largely unknown.
On "metamagical thinking":
I just spent some significant time trying to find out what "metamagical thinking" is supposed to be.
Try it yourself. You'll find many people quoting Sapolsky thus: "It's the shamans who are moving separate from everyone else, living alone, who talk with the dead, who speak in tongues, who go out with the full moon and turn into a hyena overnight, and that sort of stuff. It's the shamans who have all this metamagical thinking." What you won't find is any kind of formal definition of metamagical processes or arguments for the term.
You'll find two places in his book "Biology and Human Behavior" but in each case it is only used as an adjective describing the symptoms of schizotypal personality disorder. In the DSM this is instead described as "magical thinking," no meta involved. In "Trouble with Testosterone" Sapolsky only refers to "magical thinking."
Sapolsky appears to have just added the "meta" as a sort of unthinking affectation for a period of time and to have dropped it later. I'd be interested in evidence to the contrary.
I say all this because Hofstadter invented the term "metamagical" to describe a certain kind of highly intellectual examination of the edges of analogy and meaning in rational systems and it's a hell of a phrase. It's a shame to have Sapolsky's non-use replicating across the internet.