1. A philosophic movement of the 18th century characterized by a lively questioning of authority, keen interest in matters of politics and general culture, and an emphasis on empirical method in science. It received its impetus from the unsystematic but vigorous skepticism of Pierre Bayle, the physical doctrines of Newton, and the epistemological theories of Locke, in the preceding century. Its chief center was in France, where it gave rise to the skepticism of Voltaire , the naturalism of Rousseau, the sensationalism of Condillac, and the publication of the "Encyclopedia" by D'Alembert and Diderot. In Germany, Lessing, Mendelssohn, and Herder were representative thinkers, while the political doctrines of the leaders of the American Revolution and the speculations of Benjamin Franklin and Thomas Paine represented the movement in America.