Zola, who has so faithfully described the impulse to commit murder, did not himself commit a murder, because there were so many other characters in him. The actual murderer is in the grasp of his own disposition: the author describing the murder is swayed by a whole kingdom of impulses. Zola would know the desire for murder much better than the actual murderer would know it, he would recognise it in himself, if it really came to the surface in him, and he would be prepared for it. In such ways the criminal instincts in great men are intellectualised and turned to artistic purposes as in the case of Zola, or to philosophic purposes as with Kant, but not to actual crime.

p. 109. - Sex and Character (1903)