Henri Poincare American Quotations

It has adopted the geometry most advantageous to the species or, in other words, the most convenient.

To doubt everything, or, to believe everything, are two equally convenient solutions; both dispense with the necessity of reflection.

A very small cause which escapes our notice determines a considerable effect that we cannot fail to see, and then we say that the effect is due to chance.

If that enabled us to predict the succeeding situation with the same approximation, that is all we require, and we should say that the phenomenon had been predicted, that it is governed by the laws.

No more than these machines need the mathematician know what he does.

Thus, they are free to replace some objects by others so long as the relations remain unchanged.