Frank Sibley was trained as a philosopher in postwar Oxford. His principal teacher was Gilbert Ryle, who, understandably, had a profound influence on Sibley's way of doing philosophical analysis—an influence that is as apparent in his last papers as in his first ones.

Sibley must be credited with inaugurating the renaissance in aesthetics and philosophy of art in the English-speaking world after World War II, a renaissance that is still in full cry. He did it in 1959, in an article that, in the years since, has never ceased being discussed and cited in the literature, and, at the time of its appearance, produced a veritable deluge of essays, and even books in response or defense, that completely reinvigorated the discipline.

"Aesthetic Concepts" (1959a), as Sibley titled his inaugural article, dealt, in a surprisingly few pages, with three of the most basic and difficult...