I am delighted to know that Principia Mathematica can now be done by machinery. . . I am quite willing to believe that anything in deductive logic can be done by machinery.

The life of man is a long march through the night, surrounded by invisible foes, tortured by weariness and pain, towards a goal that few can hope to reach, and where none may tarry long.

Morally, a philosopher who uses his professional competence for anything except a disinterested search for truth is guilty of a kind of treachery.

I do not believe that I am now dreaming, but I cannot prove that I am not.

Our individual life is brief, and perhaps the whole life of mankind will be brief if measured in astronomical scale

A priori Logical propositions are such as can be known a priori without study of the actual world.

Of course not. After all, I may be wrong.