Henri Poincaré: Quotes about nature

“The scientist does not study nature because it is useful to do so. He studies it because he takes pleasure in it, and he takes pleasure in it because it is beautiful.”

Henri Poincaré book Science and Method

Part I. Ch. 1 : The Selection of Facts, p. 22
Science and Method (1908)
Context: The scientist does not study nature because it is useful to do so. He studies it because he takes pleasure in it, and he takes pleasure in it because it is beautiful. If nature were not beautiful it would not be worth knowing, and life would not be worth living. I am not speaking, of course, of the beauty which strikes the senses, of the beauty of qualities and appearances. I am far from despising this, but it has nothing to do with science. What I mean is that more intimate beauty which comes from the harmonious order of its parts, and which a pure intelligence can grasp.

Pleasure , Beauty , Nature , Study

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

Henri Poincaré

"Notice sur Halphen," Journal de l'École Polytechnique (Paris, 1890), 60ème cahier, p. 143. See also Tobias Dantzig, Henri Poincaré, Critic of Crisis: Reflections on His Universe of Discourse (1954) p. 8
Context: A scientist worthy of the name, above all a mathematician, experiences in his work the same impression as an artist; his pleasure is as great and of the same nature.... we work not only to obtain the positive results which, according to the profane, constitute our one and only affection, as to experience this esthetic emotion and to convey it to others who are capable of experiencing it.

Pleasure , Nature

“Now what is science? …it is before all a classification, a manner of bringing together facts which appearances separate, though they are bound together by some natural and hidden kinship. Science, in other words, is a system of relations. …it is in relations alone that objectivity must be sought. …it is relations alone which can be regarded as objective.
External objects… are really objects and not fleeting and fugitive appearances, because they are not only groups of sensations, but groups cemented by a constant bond. It is this bond, and this bond alone, which is the object in itself, and this bond is a relation.”

Henri Poincaré book The Value of Science

Source: The Value of Science (1905), Ch. 11: Science and Reality

Nature , Appearance , Science

“Time and Space … It is not nature which imposes them upon us, it is we who impose them upon nature because we find them convenient.”

Henri Poincaré book The Value of Science

Le temps et l’espace... Ce n’est pas la nature qui nous les impose, c’est nous qui les imposons à la nature parce que nous les trouvons commodes.
Introduction, p. 13
The Value of Science (1905)

Nature , Time

“Mathematics have a triple aim. They must furnish an instrument for the study of nature. But that is not all: they have a philosophic aim and, I dare maintain, an esthetic aim. They must aid the philosopher to fathom the notions of number, of space, of time. And above all, their adepts find therein delights analogous to those given by painting and music. They admire the delicate harmony of numbers and forms; they marvel when a new discovery opens to them an unexpected perspective; and has not the joy they thus feel the esthetic character, even though the senses take no part therein? Only a privileged few are called to enjoy it fully, it is true, but is not this the case for all the noblest arts?
This is why I do not hesitate to say that mathematics deserve to be cultivated for their own sake, and the theories inapplicable to physics as well as the others. Even if the physical aim and the esthetic aim were not united, we ought not to sacrifice either.”

Henri Poincaré book The Value of Science

Source: The Value of Science (1905), Ch. 5: Analysis and Physics

Art , Music , Feeling , Mathematics

“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 book The Value of Science

Source: The Value of Science (1905), Ch. 2: The Measure of Time

Law , Nature , Thinking , Success

“We see that experience plays an indispensable role in the genesis of geometry; but it would be an error thence to conclude that geometry is, even in part, an experimental science. If it were experimental it would be only approximative and provisional. And what rough approximation!
…The object of geometry is the study of a particular 'group'; but the general group concept pre-exists… in our minds. It is imposed on us, not as form of our sense, but as form of our understanding. Only, from among all the possible groups, that must be chosen… will be… the standard to which we shall refer natural phenomena.
Experience guides us in this choice without forcing it upon us; it tells us not which is the truest geometry, but which is the most convenient.
Notice that I have been able to describe the fantastic worlds… imagined without ceasing to employ the language of ordinary geometry.”

Henri Poincaré book Science and Hypothesis

Source: Science and Hypothesis (1901), Ch. IV: Space and Geometry, Conclusions (1905) Tr. https://books.google.com/books?id=5nQSAAAAYAAJ George Bruce Halstead

World , Error , Imagination , Understanding

“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 book The Value of Science

Cette harmonie que l’intelligence humaine croit découvrir dans la nature, existe-t-elle en dehors de cette intelligence ? Non, sans doute, une réalité complètement indépendante de l’esprit qui la conçoit, la voit ou la sent, c’est une impossibilité.
Introduction, p. 14
The Value of Science (1905)

Feeling , Intelligence , Nature , Thinking