Man’s chief difference from the brutes lies in the exuberant excess of his subjective propensities - his predominance over them simply and solely in the number and in the fantastic and unnecessary character of his wants, physical, moral, aesthetic, and intellectual. Had his whole life not been a quest for the superfluous, he would never have established himself as inexpugnably as he has done in the necessary. And from the consciousness of this he should draw the lesson that his wants are to be trusted; that even when their gratification seems farthest off, the uneasiness they occasion is still the best guide of his life, and will lead him to issues entirely beyond his present powers of reckoning. Prune down his extravagance, sober him, and you undo him.
- William James, “Reflex Action and Theism” (1881)