Let the picture imitate nothing; let it nakedly present its raison d'être. We should indeed be ungrateful were we to deplore the absence of all those things flowers, or landscape, or faces whose mere reflection it might have been. Nevertheless, let us admit that the reminiscence of natural forms cannot be absolutely banished; not yet, at all events. An art cannot be raised to the level of a pure effusion at the first step.

Du Cubisme (1912)