Alembert, Jean le Rond d'[alãbair]
Philospher and mathematician, born in Paris, France. Brought up as a foundling, he was given an annuity from his father and studied law, medicine, and mathematics at the Collège Mazarin. In 1743 he published Traité de dynamique, developing the mathematical theory of Newtonian dynamics, including the principle later named after him. Until 1758 he was Denis Diderot's principal collaborator on the Encyclopédie, of which he was the scientific editor, and wrote the Discours préliminaire, proclaiming the philosophy of the French Enlightenment.