any of the literary men, scientists, and thinkers of 18th-century France who were united, in spite of divergent personal views, in their conviction of the supremacy and efficacy of human reason.

Inspired by the philosophic thought of René Descartes (Descartes, René), the Skepticism of the Libertins, or freethinkers, and the popularization of science by Bernard de Fontenelle, the philosophes expressed support for social, economic, and political reforms, occasioned by sectarian dissensions within the church, the weakening of the absolute monarchy, and the ruinous wars that had occurred toward the end of Louis XIV's reign. In the early part of the 18th century, the movement was dominated by Voltaire and Montesquieu, but that restrained phase became more volatile in the second half of the century. Denis Diderot (Diderot, Denis), Jean-Jacques Rousseau (Rousseau, Jean-Jacques), Georges-Louis Leclerc (Buffon, Georges-Louis Leclerc, count de) de Buffon, Étienne Bonnot de Condillac (Condillac, Étienne Bonnot de), Anne-Robert-Jacques Turgot (Turgot, Anne-Robert-Jacques, baron de l'Aulne), and the Marquis de Condorcet were among the philosophes who devoted their energies to compiling the Encyclopédie (q.v.), one of the great intellectual achievements of the century.