Logic sometimes makes monsters. For half a century we have seen a mass of bizarre functions which appear to be forced to resemble as little as possible honest functions which serve some purpose.

All that we can hope from these inspirations, which are the fruits of unconscious work, is to obtain points of departure for such calculations. As for the calculations themselves, they must be made in the second period of conscious work which follows the inspiration, and in which the results of the inspiration are verified and the consequences deduced.‎

Thought is only a flash between two long nights, but this flash is everything.

To invent is to discern, to choose.

How is error possible in mathematics?

It is through science that we prove, but through intuition that we discover.

Experiment is the sole source of truth.