Everything was becoming allegorical, understood by the group mind, and especially this: "You're either on the bus … or off the bus."

On Kesey's coining of the phrase "on the bus", in The Electric Kool-Aid Acid Test (1968), Ch. VI : The Bus; as Paul Grushkin reports, in Dead Letters: The Very Best Grateful Dead Fan Mail (2011), p. 120, the statement became a famous evocation of an attitude

The phrase became a metaphor for 1960s culture rethinking — if you were "on the bus" you were "with it."