It is almost everywhere the case that soon after it is begotten the greater part of human wisdom is laid to rest in repositories.

Doubt must be no more than vigilance, otherwise it can become dangerous.

It not seldom happens that in the purposeless rovings and wanderings of the imagination we hunt down such game as can be put to use by our purposeful philosophy in its well-ordered household.

What we have to discover for ourselves leaves behind in our mind a pathway that can be used on another occasion.

Man is a masterpiece of creation, if only because no amount of determinism can prevent him from believing that he acts as a free being.

I have remarked very clearly that I am often of one opinion when I am lying down and of another when I am standing up.

Just as the performance of the vilest and most wicked deeds requires spirit and talent, so even the greatest demand a certain insensitivity which under other circumstances we would call stupidity.