Laplace, Pierre Simon de

(1749–1827)

The French mathematician is remembered in philosophy partly for his contributions to probability theory, and also for his strict determinism . He himself proved the mechanical stability of the solar system within Newtonian mechanics, thereby removing the need for any regulation by divine intervention. It is this that occasioned his celebrated remark to Napoleon about God: ‘Je n’ai pas besoin de cette hypothèse’: I have no need of that hypothesis. His determinism is frequently presented in the figure of a superhuman intelligence, to whom the entire state of nature at a time is known, and who can therefore compute the way it will evolve through subsequent times. Laplace, however, accepted that human beings would have to make do with probabilities. His Essai philosophique sur les probabilités (1814, trs. as A Philosophical Essay on Probabilities, 1951) is famous not only for its mathematical originality, but for the confidence with which Laplace applies inverse methods to give probabilities for such things as the rising of the sun or the correctness of a verdict by a jury of a given size. His reliance on both the rule of succession and on the principle of indifference have been subsequently criticized.