  Drawing on the work of Pepper and D. W. Prall (1929, 1936), Lewis held that an aesthetic appreciation of art is based on the contemplation of an “aesthetic essence” presented by the work. Lewis describes an aesthetic essence as “a certain composition of sense or qualia” and as “an immediate apprehension of sense” (1946, 188). Lewis also writes in this context of “qualitatively identical items of content (Santayana’s ‘essences’?)” (1946, 18), thereby suggesting he is not quite sure whether his notion of an essence comes close to that of George Santayana, who described essences as the immediate data of experience (1923). (For background, see the entry on Clarence Irving Lewis, and especially the section on “the given.”)