Love can only flourish as long as it is free and spontaneous; it tends to be killed by the thought that it is a duty. To say that it is your duty to love so-and-so is the surest way to cause you to hate him or her.

We know too much and feel too little. At least, we feel too little of those creative emotions from which a good life springs.

The fundamental concept in social science is Power, in the same sense in which Energy is the fundamental concept in physics.

...the nonexistence of God makes more difference to some of us than to others. To me, it means that there is no absolute morality, that moralities are sets of social conventions devised by humans to satisfy their needs.

Science does not aim at establishing immutable truths and eternal dogmas; its aim is to approach the truth by successive approximations, without claiming that at any stage final and complete accuracy has been achieved.

Awareness of universals is called conceiving, and a universal of which we are aware is called a concept.

Abstract work, if one wishes to do it well, must be allowed to destroy one's humanity; one raises a monument which is at the same time a tomb, in which, voluntarily, one slowly inters oneself.