Experiment is the sole source of truth. It alone can teach us something new; it alone can give us certainty.

Doubt everything or believe everything: these are two equally convenient strategies. With either we dispense with the need for reflection.

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

Science is built up of facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house.

A very small cause, which escapes us, determines a considerable effect which we cannot ignore, and we say that this effect is due to chance.

Deviner avant de démontrer! Ai-je besoin de rappeler que c'est ainsi que se sont faites toutes les découvertes importantes.

When the physicists ask us for the solution of a problem, it is not drudgery that they impose on us, on the contrary, it is us who owe them thanks.

A reality completely independent of the spirit that conceives it, sees it, or feels it, is an impossibility. A world so external as that, even if it existed, would be forever inaccessible to us.

Every good mathematician should also be a good chess player and vice versa.