Set and setting: The missing factors in Chris Letheby’s psychedelic philosophy
South African Journal of Philosophy September 11, 2025 W. F. Smith
Chris Letheby's two-factor account of psychedelic therapy emphasizes neural, cognitive, and phenomenological plasticity as the first factor, and new self-modelling discovered during the experience and reinforced in integration as the second. This article argues that Letheby's theory overlooks the importance of non-individualistic aspects, traditionally called "set and setting." "Set" corresponds to embodiment—how the subject's bodily state shapes the experience—and "setting" corresponds to embeddedness—how the environment influences the content, quality, and therapeutic value of the psychedelic experience. The principles of set and setting can critically inform Letheby's theory by filling in these missing phenomenological components.