A man who sets out to justify his existence and his activities has to distinguish two different questions. The first is whether the work which he does is worth doing; and the second is why he does it (whatever its value may be).

Young men should prove theorems, old men should write books.

In [great mathematics] there is a very high degree of unexpectedness, combined with inevitability and economy.

Bombs are probably more merciful than bayonets

Asked if he believes in one G-d, a mathematician answered: "Yes, up to isomorphism".

A man who sets out to justify his existence and his activities has to distinguish two different questions. The first is whether the work which he does is worth doing; and the second is why he does it (whatever its value may be).

Beauty is the first test: there is no permanent place in the world for ugly mathematics.