" Psilocybes gave our hominid ancestors “access to realms of supernatural power,” “catalyzed the emergence of human self-reflection,” and “brought us out of the animal mind and into the world of articulated speech and imagination.” This last hypothesis about the invention of language turns on the concept of synesthesia, the conflation of the senses that psychedelics are known to induce: under the influence of psilocybin, numbers can take on colors, colors attach to sounds, and so on. Language, he contends, represents a special case of synesthesia, in which otherwise meaningless sounds become linked to concepts. Hence, the stoned ape: by giving us the gifts of language and self-reflection psilocybin mushrooms made us who we are, transforming our primate ancestors into Homo sapiens. "
― Michael Pollan , How to Change Your Mind: What the New Science of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression, and Transcendence