The science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen.

A great discovery is a fact whose appearance in science gives rise to shining ideas, whose light dispels many obscurities and shows us new paths.

We must keep our freedom of mind, ... and must believe that in nature what is absurd, according to our theories, is not always impossible.

Tout est poison, rien n'est poison, tout est une question de dose. Everything is poisonous, nothing is poisonous, it is all a matter of dose.

We must alter theory to adapt it to nature, but not nature to adapt it to theory.‎

We must remain, in a word, in an intellectual disposition which seems paradoxical, but which, in my opinion, represents the true mind of the investigator. We must have a robust faith and yet not believe.

The joy of discovery is certainly the liveliest that the mind of man can ever feel.