Introduction
At sufficiently high doses, all classical psychedelics can produce an experience that users describe as the temporary dissolution of the boundary between self and world -- a loss of the sense of being a separate individual observing reality from behind the eyes. This phenomenon, known as ego dissolution, is the most distinctive and therapeutically significant aspect of the psychedelic experience. It is closely related to what researchers call the "mystical experience" -- a state characterized by unity, transcendence, sacredness, deeply felt positive mood, and a sense of encountering ultimate reality. Understanding ego dissolution has moved from philosophical speculation to quantitative neuroscience.
