A sane mind should not be guilty of a logical fallacy, yet there are very fine minds incapable of following mathematical demonstrations.
Henri Poincare

A scientist worthy of his name, about all a mathematician, experiences in his work the same impression as an artist; his pleasure is as great and of the same nature.
Henri Poincare

A small error in the former will produce an enormous error in the latter.
Henri Poincare

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.
Henri Poincare

Absolute space, that is to say, the mark to which it would be necessary to refer the earth to know whether it really moves, has no objective existence.
Henri Poincare

Facts do not speak.
Henri Poincare

Geometry is not true, it is advantageous.
Henri Poincare

How is an error possible in mathematics?
Henri Poincare

Hypotheses are what we lack the least.
Henri Poincare

Ideas rose in clouds; I felt them collide until pairs interlocked, so to speak, making a stable combination.
Henri Poincare

If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living.
Henri Poincare

If one looks at the different problems of the integral calculus which arise naturally when one wishes to go deep into the different parts of physics, it is impossible not to be struck by the analogies existing.
Henri Poincare

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.
Henri Poincare

If we knew exactly the laws of nature and the situation of the universe at the initial moment, we could predict exactly the situation of the same universe at a succeeding moment.
Henri Poincare

In the old days when people invented a new function they had something useful in mind.
Henri Poincare

Invention consists in avoiding the constructing of useless contraptions and in constructing the useful combinations which are in infinite minority.
Henri Poincare

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

It is far better to foresee even without certainty than not to foresee at all.
Henri Poincare

It is the harmony of the diverse parts, their symmetry, their happy balance; in a word it is all that introduces order, all that gives unity, that permits us to see clearly and to comprehend at once both the ensemble and the details.
Henri Poincare

It is through science that we prove, but through intuition that we discover.
Henri Poincare