The world of ideas is not revealed to us in one stroke; we must both permanently and unceasingly recreate it in our consciousness.

Algebra is rich in structure but weak in meaning.

Topology is precisely the mathematical discipline that allows the passage from local to global.

The world of ideas is not revealed to us in one stroke; we must both permanently and unceasingly recreate it in our consciousness.

The importance of the "New Mathematics" lies mainly in the fact that it has taught us the difference between the disc and the circle.

If one must choose between rigour and meaning, I shall unhesitatingly choose the latter.

I believe that proving is not a natural activity for mathematicians.