turn on, tune in (and) drop out
used as a slogan for, and invitation to join, the hippy counterculture. Credited to Timothy Leary (1920–96) the self-styled high priest of LSD, this pocket-philosophy combined TURN ON (to use drugs), 'tune in' (to become culturally aware) and
DROP OUT (to cease to be part of a conventional society) in a catchphrase that seemed to be more than the sum of its parts
US, 1968