Wednesday, May 07, 2008

Laplace (1749-1827)


By Richard E. Noble

Pierre Simon Laplace was a mathematician and astronomer. He was a poor boy from a peasant background. He seems to have had a knack for kissing-up and getting people to like him. This trait got his neighbors to pay to educate him and helped him to success in a political career in very perilous times. He was a brilliant scientist but, nevertheless, always willing to steal material from any source.
After his rise from peasant-hood, he succeeded to what most biographers have characterized as a snob. He hid his background and treated even old benefactors shabbily. He is renowned as the most famous and outspoken atheist of his day. When criticized by Napoleon Bonaparte for never mentioning God in his famous work on the heavens, "Mecanique Celeste", he is recorded to have answered that he had no need for such an hypothesis. After Lavoisier got his head chopped off in the Revolution, Laplace and Lagrange saved their necks by slipping into the now vacant position at the national powder works. When Napoleon came to power, Laplace once again ingratiated himself into a cushy government job as secretary of the interior. He didn't last there long but was soon bounced, conveniently, into another governmental department. By the time Louis XVIII came along he had a seat in the Chamber of Peers and was now the Marquis de Laplace. He is acclaimed by some to be the Isaac Newton of France. His "Mecanique Celeste" is, in fact, a translation of Newton's "Principia" into the language of infinitesimal calculus and a completion of Newton ideas in many details. It may have been his attention to such details that gave him the confidence to counter Newton's need for an occasional intervening God. Where Newton needed God as a final explanation, Laplace had mathematical and physical facts.
Laplace is also noted for stating that with enough physical science, principles and knowledge of the universe, a superior intellect would not only be capable of reconstructing the heavenly past but could also predict the future of the universe. So now along with his being classified an atheist, Laplace was also considered a determinist. I suppose the inference here is that if one felt that the future of the stars was predictable then so too would be the future of mankind. I don't see the connection, but what do I know. One's knowledge of the eventual flow or course of a river tells us why we humans are here on earth; what our destinies and origins might be? I think not.
Whether or not M. Laplace was a good guy or a bad guy seems to depend on who you talk to. But, that he was a smart guy goes without question.
At eighteen he applied for a job to d'Alembert, the famous mathematician and Encyclopedist. LaPlace brought with him a recommendation, nevertheless, d'Alembert refused to see him. Laplace then wrote him a letter on the general principles of mechanics. Laplace got the position. D'Alembert obviously believed that it was not, who you know, but, what you know that counted.
Laplace re-established Kant's nebular hypothesis stating that the solar system evolved from gases rotating around the sun. The gases formed rings which then cooled and formed the planets etc.
He not only illuminated every branch of physics with his "Laplace equations" but did lasting work in the theory of probabilities. He calculated the earth's dynamical ellipticity. He developed an analytical theory of the tides. He deduced the mass of the moon. He improved methods for determining the orbits of comets. In 1798 General Bonaparte even took him to Egypt to study the stars from the top of the Pyramids.