Henri Poincaré - The Value of Science (1905)

40 Sourced Quotes

View all Henri Poincaré Quotes
The scientific fact is only the crude fact translated into a convenient language.

Henri Poincaré
As we can not give a general definition of energy, the principle of the conservation of energy signifies simply that there is something which remains constant.

Henri Poincaré
The aim of science is not things themselves, as the dogmatists in their simplicity imagine, but the relation between things.

Henri Poincaré
Scientific laws are not artificial creations; we have no reason to regard them as accidental, though it be impossible to prove they are not.

Henri Poincaré
Ethics and science have their own domain which touch but do not interpenetrate. The one shows us to what goal we should aspire, the other, given the goal, teaches us how to attain it. So they can never conflict since they can never meet. There can no more be immoral science than there can be scientific morals.

Henri Poincaré
We can not know all facts and it is necessary to choose those which are worthy of being known.

Henri Poincaré
The stars send us not only that visible and gross light which strikes our bodily eyes, but from them also comes to us a light far more subtle, which illuminates our minds.

Henri Poincaré
Logic and intuition have each their necessary role. Each is, indispensable. Logic, which alone can give certainty, is the instrument of demonstration; intuition is the instrument of invention.

Henri Poincaré
One geometry cannot be more true than another; it can only be more convenient.

Henri Poincaré
If science is feared, it is above all because it cannot give us happiness.

Henri Poincaré
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.

Henri Poincaré
Today we no longer beg of nature; we command her, because we have discovered certain of her secrets and shall discover others each day. We command her in the name of laws she cannot challenge, because they are hers; these laws we do not madly ask her to change, we are the first to submit to them. Nature can only be governed by obeying her.

Henri Poincaré
Man, then, can not be happy through science, but to-day he can be much less be happy without it.

Henri Poincaré
Science is a rule of action which is successful...

Henri Poincaré
Scientific truth, which is demonstrated, can in no way be likened to moral truth, which is felt.

Henri Poincaré
What is a good definition? For the philosopher or the scientist, it is a definition which applies to all the objects to be defined, and applies only to them; it is that which satisfies the rules of logic. But in education it is not that; it is one that can be understood by the pupils.

Henri Poincaré
Pure logic could never lead us to anything but tautologies; it can create nothing new; not from it alone can any science issue.

Henri Poincaré
The science of physics does not only give us [mathematicians] an opportunity to solve problems, but helps us to discover the means of solving them, and it does this in two ways: it leads us to anticipate the solution and suggests suitable lines of argument.

Henri Poincaré
The stars are majestic laboratories, gigantic crucibles, such as no chemist could dream.

Henri Poincaré
Sometimes truth frightens us. And in fact we know that it is sometimes deceptive, that it is a phantom never showing itself for a moment except to ceaselessly flee, that it must be pursued further and ever further without ever being attained.

Henri Poincaré
Does the harmony the human intelligence thinks it discovers in nature exist outside of this intelligence? No, beyond doubt, a reality completely independent of the mind which conceives it, sees or feels it, is an impossibility.

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

Henri Poincaré
We have not a direct intuition of simultaneity, nor of the equality of two durations. If we think we have this intuition, this is an illusion. We replace it by the aid of certain rules which we apply almost always without taking count of them.
... We... choose these rules, not because they are true, but because they are the most convenient, and we may recapitulate them as follows: "The simultaneity of two events, or the order of their succession, the equality of two durations, are to be so defined that the enunciation of the natural laws may be as simple as possible. In other words, all these rules, all these definitions, are only the fruit of an unconscious opportunism."

Henri Poincaré
All that is not thought is pure nothingness; since we can think only thought and all the words we use to speak of things can express only thoughts, to say there is something other than thought, is therefore an affirmation which can have no meaning.
And yet—strange contradiction for those who believe in time—geologic history shows us that life is only a short episode between two eternities of death, and that, even in this episode, conscious thought has lasted and will last only a moment. Thought is only a gleam in the midst of a long night. But it is this gleam which is everything.

Henri Poincaré
It is only through science and art that civilization is of value. Some have wondered at the formula: science for its own sake; an yet it is as good as life for its own sake, if life is only misery; and even as happiness for its own sake, if we do not believe that all pleasures are of the same quality...
Every act should have an aim. We must suffer, we must work, we must pay for our place at the game, but this is for seeing's sake; or at the very least that others may one day see.

Henri Poincaré
For an aggregate of sensations to have become a remembrance capable of classification in time, it must have ceased to be actual, we must have lost the sense of its infinite complexity, otherwise it would have remained present. It must, so to speak, have crystallized around a center of associations of ideas which will be a sort of label. It is only when they have lost all life that we can classify our memories in time as a botanist arranges dried flowers in his herbarium.

Henri Poincaré
Every good mathematician should also be a good chess player and vice versa.

Henri Poincaré
All that we can hope from these inspirations, which are the fruits of unconscious work, is to obtain points of departure for such calculations. As for the calculations themselves, they must be made in the second period of conscious work which follows the inspiration, and in which the results of the inspiration are verified and the consequences deduced.

Henri Poincaré
If all the parts of the universe are interchained in a certain measure, any one phenomenon will not be the effect of a single cause, but the resultant of causes infinitely numerous; it is, one often says, the consequence of the state of the universe the moment before.

Henri Poincaré
How is it that there are so many minds that are incapable of understanding mathematics?... the skeleton of our understanding,... and actually they are the majority.... We have here a problem that is not easy of solution, but yet must engage the attention of all who wish to devote themselves to education.

Henri Poincaré