The scientific and intellectual developments of the 17th cent.—the discoveries of Isaac Newton, the rationalism of Réné Descartes, the skepticism of Pierre Bayle, the pantheism of Benedict de Spinoza, and the empiricism of Francis Bacon and John Locke—fostered the belief in natural law and universal order and the confidence in human reason that spread to influence all of 18th-century society. Currents of thought were many and varied, but certain ideas may be characterized as pervading and dominant. A rational and scientific approach to religious, social, political, and economic issues promoted a secular view of the world and a general sense of progress and perfectibility.
The major champions of these concepts were the philosophes, who popularized and promulgated the new ideas for the general reading public. These proponents of the Enlightenment shared certain basic attitudes. With supreme faith in rationality, they sought to discover and to act upon universally valid principles governing humanity, nature, and society. They variously attacked spiritual and scientific authority, dogmatism, intolerance, censorship, and economic and social restraints. They considered the state the proper and rational instrument of progress. The extreme rationalism and skepticism of the age led naturally to deism; the same qualities played a part in bringing the later reaction of romanticism. The Encyclopédie of Denis Diderot epitomized the spirit of the Age of Enlightenment, or Age of Reason, as it is also called.
Centered in Paris, the movement gained international character at cosmopolitan salons. Masonic lodges played an important role in disseminating the new ideas throughout Europe. Foremost in France among proponents of the Enlightenment were baron de Montesquieu, Voltaire, and comte de Buffon; Baron Turgot and other physiocrats; and Jean Jacques Rousseau, who greatly influenced romanticism. Many opposed the extreme materialism of Julien de La Mettrie, baron d' Holbach, and Claude Helvétius.
In England the coffeehouses and the newly flourishing press stimulated social and political criticism, such as the urbane commentary of Joseph Addison and Sir Richard Steele. Jonathan Swift and Alexander Pope were influential Tory satirists. Lockean theories of learning by sense perception were further developed by David Hume. The philosophical view of human rationality as being in harmony with the universe created a hospitable climate for the laissez-faire economics of Adam Smith and for the utilitarianism of Jeremy Bentham. Historical writing gained secular detachment in the work of Edward Gibbon.
In Germany the universities became centers of the Enlightenment (Ger. Aufklärung). Moses Mendelssohn set forth a doctrine of rational progress; G. E. Lessing advanced a natural religion of morality; Johann Herder developed a philosophy of cultural nationalism. The supreme importance of the individual formed the basis of the ethics of Immanuel Kant. Italian representatives of the age included Cesare Beccaria and Giambattista Vico. From America, Thomas Paine, Thomas Jefferson, and Benjamin Franklin exerted vast international influence.
Some philosophers at first proposed that their theories be implemented by "enlightened despots"—rulers who would impose reform by authoritarian means. Czar Peter I of Russia anticipated the trend, and Holy Roman Emperor Joseph II was the prototype of the enlightened despot; others were Frederick II of Prussia, Catherine II of Russia, and Charles III of Spain. The proponents of the Enlightenment have often been held responsible for the French Revolution. Certainly the Age of Enlightenment can be seen as a major demarcation in the emergence of the modern world.
See E. Cassirer, The Philosophy of the Enlightenment (tr. 1951, repr. 1955); P. Hazard, The European Mind: The Critical Years, 1690-1715 (tr. 1953, repr. 1963) and European Thought in the Eighteenth Century (tr. 1954, repr. 1963); F. E. Manuel, The Eighteenth Century Confronts the Gods (1959, repr. 1967); P. Gay, The Enlightenment: An Interpretation (2 vol., 1966-69); A. Cobban, ed., Europe in the Age of the Enlightenment (1969); L. G. Crocker, ed., The Age of Enlightenment (1969); N. Hampson, The Enlightenment (1970); F. Venturi, Utopia and Reform in the Enlightenment (1971); J. Engell, The Creative Imagination: Enlightenment to Romanticism (1981); W. E. Rex, The Attraction of the Contrary: Essays on the Literature of the French Enlightenment (1987).