“IT WAS AT THIS POINT that the idea of “shaking the snow globe,” as one neuroscientist described the psychedelic experience, came to seem more attractive to me than frightening, though it was still that too. After more than half a century of its more or less constant companionship, one’s self—this ever-present voice in the head, this ceaselessly commenting, interpreting, labeling, defending I—becomes perhaps a little too familiar. I’m not talking about anything as deep as self-knowledge here. No, just about how, over time, we tend to optimize and conventionalize our responses to whatever life brings. Each of us develops our shorthand ways of slotting and processing everyday experiences and solving problems, and while this is no doubt adaptive—it helps us get the job done with a minimum of fuss—eventually it becomes rote. It dulls us. The muscles of attention atrophy.”