On the one hand, philosophy is to keep us thinking about things that we may come to know, and on the other hand to keep us modestly aware of how much that seems like knowledge isn't knowledge

At the age of eleven, I began Euclid, with my brother as my tutor. ... I had not imagined that there was anything so delicious in the world. After I had learned the fifth proposition, my brother told me that it was generally considered difficult, but I had found no difficulty whatsoever. This was the first time it had dawned on me that I might have some intelligence.

We may often do as we please - but we cannot please as we please.

No man treats a motorcar as foolishly as he treats another human being. When the car will not go, he does not attribute its annoying behavior to sin; he does not say, 'You are a wicked motorcar, and I shall not give you any more petrol until you go.' He attempts to find out what is wrong and to set it right.

Righteousness cannot be born until self-righteousness is dead.

Any philosophy worth taking seriously would have to be built upon a firm foundation of unyielding despair.

The fact that a belief has a good moral effect upon a man is no evidence whatsoever in favor of its truth. I'm not contending in a dogmatic way that there is not a God. What I'm contending is that we don't know that there is. I don't like the word "absolute." I don't think there is anything absolute whatever. The moral law, for example, is always changing. At one period in the development of the human race, almost everybody thought cannibalism was a duty.