Pierre-Simon Laplace - Wikipedia

http://en.wikipedia.org/wiki/Laplace

French mathematician & astronomer
Born	March 23, 1749 Beaumont-en-Auge, Normandy
Died	March 5, 1827

Pierre-Simon, Marquis de Laplace (March 23, 1749, Beaumont-en-Auge, Normandy – March 5, 1827, Paris) was a French mathematician and astronomer who put the final capstone on mathematical astronomy by summarizing and extending the work of his predecessors in his five volume Mécanique Céleste (Celestial Mechanics) (1799-1825). This masterpiece translated the geometrical study of mechanics used by Isaac Newton to one based on calculus, known as physical mechanics [1].

He is also the discoverer of Laplace's equation. Although the Laplace transform is named in honor of Laplace, who used the transform in his work on probability theory, the transform was discovered originally by Leonhard Euler, the prolific eighteenth-century Swiss mathematician. The Laplace transform appears in all branches of mathematical physics — a field he took a leading role in forming. The Laplacian differential operator, much relied-upon in applied mathematics, is likewise named after him.

He became count of the Empire in 1806 and was named a marquis in 1817 after the restoration of the Bourbons.

Quotes

• What we know is not much. What we do not know is immense.
• I have no need of that hypothesis. ("Je n'ai pas besoin de cette hypothèse", as a reply to Napoleon, who had asked why he hadn't mentioned God in his book on astronomy)
• "It is therefore obvious that..." (frequently used in the Celestial Mechanics when he had proved something and mislaid the proof, or found it clumsy. Notorious as a signal for something true, but hard to prove.)
• The weight of evidence for an extraordinary claim must be proportioned to its strangeness. (known as the Principle of Laplace)