If we ought not to fear mortal truth, still less should we dread scientific truth. In the first place it can not conflict with ethics? But if science is feared, it is above all because it can give no happiness? Man, then, can not be happy through science but today he can much less be happy without it.

It is by logic that we prove, but by intuition that we discover. To know how to criticize is good, to know how to create is better.

All the scientist creates in a fact is the language in which he enunciates it. If he predicts a fact, he will employ this language, and for all those who can speak and understand it, his prediction is free from ambiguity. Moreover, this prediction once made, it evidently does not depend upon him whether it is fulfilled or not.

But for harmony beautiful to contemplate, science would not be worth following.

Need we add that mathematicians themselves are not infallible?

Science is built up with 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.

All great progress takes place when two sciences come together, and when their resemblance proclaims itself, despite the apparent disparity of their substance.