It is not contended here that these primitive men did wear clothes any more than they did weave rushes; but merely that we have not enough evidence to know whether they did or not. But it may be worthwhile to look back for a moment at some of the very few things that we do know and that they did do. . . . we do know that they did have pictures; and the pictures have remained. And there remains with them, as already suggested, the testimony to something that is absolute and unique; that belongs to man and to nothing else except man; that is a difference of kind and not a difference of degree. A monkey does not draw clumsily and a man cleverly; a monkey does not begin the art of representation and a man carry it to perfection. A monkey does not do it at all; he does not begin to do it at all; he does not begin to begin to do it at all. A line of some kind is crossed before the first faint line can begin.
Quote from the chapter called "Professors and Prehistoric Men" in The Everlasting Man