Do you call it doubting to write down on a piece of paper that you doubt? If so, doubt has nothing to do with any serious business. But do not make believe; if pedantry has not eaten all the reality out of you, recognize, as you must, that there is much that you do not doubt, in the least. Now that which you do not at all doubt, you must and do regard as infallible, absolute truth.

This branch of mathematics [Probability] is the only one, I believe, in which good writers frequently get results which are entirely erroneous.

There is a kink in my damned brain that prevents me from thinking as other people think.

We cannot begin with complete doubt.

Law is par excellence the thing that wants a reason. Now the only possible way of accounting for the laws of nature, and for uniformity in general, is to suppose them results of evolution.

All the progress we have made in philosophy ... is the result of that methodical skepticism which is the element of human freedom.

It is a common observation that those who dwell continually upon their expectations are apt to become oblivious to the requirements of their actual situation.