Quotes from 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.

Science is facts.

Doubting everything and believing everything are two equally convenient solutions that guard us from having to think

One would have to have completely forgotten the history of science so as to not remember that the desire to know nature has had the most constant and the happiest influence on the development of mathematics.

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.

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

Need we add that mathematicians themselves are not infallible?

Sociology is the science with the greatest number of methods and the least results.

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.

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

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

Talk with M. Hermite. He never evokes a concrete image, yet you soon perceive that the more abstract entities are to him like living creatures.

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

The mathematical facts worthy of being studied are those which, by their analogy with other facts, are capable of leading us to the knowledge of a physical law.

It is by logic we prove. It is by intuition we discover.

Experiment is the sole source of truth. It alone can teach us something new; it alone can give us certainty.

Geometry is not true, it is advantageous.

Experiment is the sole source of truth.

We also know how cruel the truth often is, and we wonder whether delusion is not more consoling.

To invent is to discern, to choose.

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

Hypotheses are what we lack the least.

What is it indeed that gives us the feeling of elegance in a solution, in a demonstration?

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