Mathematician and Astronomer.

Pierre-Simon, marquis de Laplace (23 March 1749 – 5 March 1827) was a French mathematician and astronomer whose work was pivotal to the development of mathematical astronomy and statistics. He summarized and extended the work of his predecessors in his five-volume Mécanique Céleste (Celestial Mechanics) (1799–1825). This work translated the geometric study of classical mechanics to one based on calculus, opening up a broader range of problems. In statistics, the so-called Bayesian interpretation of probability was mainly developed by Laplace.

Laplace formulated Laplace's equation, and pioneered the Laplace transform which appears in many branches of mathematical physics, a field that he took a leading role in forming. The Laplacian differential operator, widely used in mathematics, is also named after him. He restated and developed the nebular hypothesis of the origin of the solar system and was one of the first scientists to postulate the existence of black holes and the notion of gravitational collapse.

Laplace is remembered as one of the greatest scientists of all time. Sometimes referred to as the French Newton or Newton of France, he possessed a phenomenal natural mathematical faculty superior to that of any of his contemporaries.

Sources:

1.) "Napoleon replies: "How comes it, then, that Laplace was an atheist? At the Institute neither he nor Monge, nor Berthollet, nor Lagrange believed in God. But they did not like to say so." Baron Gaspard Gourgaud, Talks of Napoleon at St. Helena with General Baron Gourgaud (1904), page 274.

2.) Napoleon said to Laplace: "You have written this huge book on the system of the world without once mentioning the author of the universe [God]." Laplace replied: "Sire, I had no need of that hypothesis." Quoted in Augustus De Morgan, A Budget of Paradoxes, London, Longmans, Green and Co., 1872. As found in http://www-history.mcs.st-andrews.ac.uk/~history/Quotations/Laplace.html, accessed 13 February 2006.

3.) "The Catholic newspaper La Quotidienne [The Daily] announced that Laplace had died in the arms of two curés (priests), implying that he had a proper Catholic end, but this is not credible. To the end, he remained a skeptic, wedded to his deterministic creed and to an uncompromised ethos derived from his vast scientific experience." Roger Hahn, Pierre Simon Laplace, 1749-1827: a determined scientist, page 204.

4.) Roger Hahn (2005). Pierre Simon Laplace, 1749-1827: A Determined Scientist. Harvard University Press. p. 202. ISBN 9780674018921. "Publicly, Laplace maintained his agnostic beliefs, and even in his old age continued to be skeptical about any function God might play in a deterministic universe."