The song is perhaps best known for its opening lines: “Timothy Leary’s dead / No, n-n-no he’s outside looking in”, which allude to Leary’s use of eastern mysticism (most notably The Tibetan Book of the Dead) to frame the psychedelic experience.
https://github.com/davepinch/pinchy.cc/blob/master/content/topics/religion/buddhism/bardo-thodol/the-tibetan-book-of-the-dead.md