“The subject is to the painter what the rails are to the locomotive. He cannot do without it. In fact, when he refuses to seek or accept a subject, his own plastic methods and his own esthetic theories become his subject instead. And even if he escapes them, he himself becomes the subject of his work. He becomes nothing but an illustrator of his own state of mind, and in trying to liberate himself he falls into the worst sort of slavery.”
Excerpted from: Schapiro, Fred, ed. The Yale Book of Quotations. New Haven: Yale University Press, 2006.