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.”

“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.”

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

“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.”

“Facts do not speak.”

“Point set topology is a disease from which the human race will soon recover.”

“Just as houses are made of stones, so is science made of facts.”

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

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

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

“Mathematicians are born, not made.”

“Thought is only a flash between two long nights, but this flash is everything.”

“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.”

“Geometry is not true, it is advantageous.”

“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.”

“The mind uses its faculty for creativity only when experience forces it to do so.”

“How is an error possible in mathematics?”

“Mathematical discoveries, small or great are never born of spontaneous generation.”

“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.”

“To invent is to discern, to choose.”