More important than pessimism was the doctrine of the primacy of the will. It is obvious that this doctrine has no necessary logical connection with pessimism, and those who held it after Schopenhauer frequently found in it a basis for optimism. In one form or another, the doctrine that will is paramount has been held by many modern philosophers, notably Nietzsche, Bergson, James, and Dewey. It has, moreover, acquired a vogue outside the circles of professional philosophers. And in proportion as will has gone up in the scale, knowledge has gone down. This is, I think, the most notable change that has come over the temper of philosophy in our age. It was prepared by Rousseau and Kant, but was first proclaimed in its purity by Schopenhauer.

Bertrand Russell, History of Western Philosop…, loc. 2752