Because Pierre-Simon de Laplace was secretive about his background, little is known of his early life; he may have been ashamed of his past and kept the details to himself. He was born on March 23, 1749, at Beaumont-en-Auge, Normandy, France. It has been suggested that he came from a poor family and affluent neighbors helped him get an education. Other evidence, however, supports the contention that he came from a middle-class family. At any rate, Laplace was extremely intelligent; when only 18 years old he went to Paris and obtained a professorship in mathematics, based on a paper he had written on mechanics.

Laplace, working with Antoine-Laurent Lavoisier, conducted research on the heats of various substances. The two gave birth to the science of thermochemistry when they demonstrated in 1780 that the amount of heat necessary to decompose an object was equal to the heat evolved when the object had been...