# Alex Peek blog

List of posts Blog archive About

Sunday, August 19, 2018

## Henri Poincaré: The Last Universalist

Photo source: Wikimedia Commons

Henri Poincaré (1854-1912) was a French mathematician and physicist best known for his contributions to topology and special relativity. After the death of Poincaré, politician and mathematician Paul Painleve said,

"With the disappearance of the great French mathematician has disappeared the one man whose thought could carry all other thoughts, the one mind who, through a sort of rediscovery, could penetrate to its very depth all the knowledge which the mind of man can comprehend... the potent luminous brain will not be there to coordinate disjointed research..." (Eulogy, 1912)

The rest of this post is some quotes from Poincaré.

### Complexity

"If we study the history of science, we see happen two inverse phenomena... sometimes simplicity hides under complex appearances; sometimes it is the simplicity which is apparent, and which disguises extremely complicated realities." (Science and Hypothesis, 1901)

### Causation

"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 the universe the moment before." (The Value of Science, 1905)

### Skepticism

"To doubt everything or to believe everything are two equally convenient solutions; both dispense with the necessity of reflection." (Science and Hypothesis, 1901)

"Induction applied to the physical sciences is always uncertain, because it rests on the belief in a general order of the universe..." (Science and Hypothesis, 1901)

### Intuition

"...mathematical reasoning has itself a sort of creative virtue and consequently differs from a syllogism." (Science and Hypothesis, 1901)

"It is by logic that we prove, but by intuition that we discover. To know how to criticize is good, to know how to create is better." (Science and Method, 1908)