It is my conviction that pure mathematical construction enables us to discover the concepts and the laws connecting them, which gives us the key to the understanding of nature ... In a certain sense, therefore, I hold it true that pure thought can grasp reality, as the ancients dreamed.

Dostoevsky gives me more than any scientist, more than Gauss.

Assumptions are made and most assumptions are wrong.

One should not pursue goals that are easily achieved. One must develop an instinct for what one can just barely achieve through one’s greatest efforts.

The wing structure of the hornet, in relation to its weight, is not suitable for flight, but he does not know this and flies anyway.

It is a very grave mistake to think that the enjoyment of seeing and searching can be promoted by means of coercion and a sense of duty.

I think and think for months and years. Ninety-nine times, the conclusion is false. The hundredth time I am right.