In the light of modern speculation upon the philosophy of the fine arts, Diderot makes no commanding figure, because he is so egregiously unsystematic. But as Goethe said, in a piece where he was withstanding Diderot to the face, _die hoechste Wirkung des Geistes ist, den Geist hervorzurufen_--the highest influence of mind is to call out mind. This stimulating provocation of the intelligence was the master faculty in Diderot. For the sake of that men are ready to pardon all excesses, and to overlook many offences against the law of Measure. From such a point of view, Goethe's treatment of Diderot's Essay on Painting (written in 1765, but not given to the world until 1796) is an instructive lesson. "Diderot's essay," he wrote to Schiller, "is a magnificent work, and it speaks even more usefully to the poet than to the painter, though for the painter, too, it is a torch of powerful illumination." Yet Diderot's critical principle in the essay was exactly opposite to Goethe's; and when Goethe translated some portions of it, he was forced to add a commentary of stringent protest. Diderot, as usual, energetically extols nature, as the one source and fountain of true artistic inspiration. Even in what looks to us like defect and monstrosity, she is never incorrect. If she inflicts on the individual some unusual feature, she never fails to draw other parts of the system into co-ordination and a sort of harmony with the abnormal element. We say of a man who passes in the street that he is ill-shapen. Yes, according to our poor rules; but according to nature, it is another matter. We say of a statue that it is of fine proportions. Yes, according to our poor rules; but according to nature?[55] [55] x. 481, 462.