…it may well be true that Sgt. Pepper is more bound to a moment than in a lot of the Beatles’ earlier music. The postadolescent philosophizing and premusicianly jamming of some of this music sounds silly now. But if the energy of early rock and roll is bound up in the realization of personal autonomy, this music is about beginning to discover that autonomy carries with it identifiable powers and — these sometimes take a while to come to the surface — responsibilities. Often it’s quite delighted with its incipient maturity. And that doesn’t sound silly at all.
Robert Christgau, Dec. 1967