Enlightenment: An eighteenth-century philosophical movement in Europe and America that critically examined traditional ideas and institutions, privileged reason, and championed progress. Thinkers associated with the Enlightenment sought to uncover fundamental principles governing humanity and nature and believed in universal order and the perfectability of the individual and society. As rationalists and empiricists, they advocated use of the scientific method, observation, and experience to understand — and modify — both the natural world and human society. Notably, proponents themselves used the term Enlightenment in reference to the movement and their worldview, believing that reason could overcome ignorance, intolerance, superstition, and tyranny with the light of truth. As German philosopher Immanuel Kant asserted in his essay “Was ist Aufklärung?” (“What Is Enlightenment?”) (1784):
If it is asked whether we at present live in an enlightened age, the answer is: No, but we do live in an age of enlightenment. As things are at present, we still have a long way to go before men as a whole can be in a position (or can even be put in a position) of using their own understanding confidently and well in religious matters, without outside guidance. But we do have distinct indications that the way is now being cleared for them to work freely in this direction, and that the obstacles to universal enlightenment, to man’s emergence from his self-incurred immaturity are gradually becoming fewer.
Kant also invoked the Enlightenment motto, “sapere dare,” often translated as “have courage to use your own understanding” or, more briefly, as “dare to know” or “dare to think.”
Enlightenment thinkers were particularly concerned with religion and governance. They sought to humanize religion, rejecting religious dogma and promoting tolerance, and opposed religious interference with science, arguing that religion had nothing to do with inquiries into the natural and human worlds. In search of a universal “natural religion,” many rejected organized religion and embraced deism, belief in the existence of God based on reason and experience rather than revelation. Deists viewed God as an impersonal deity, the source of the universe, and linked reverence and worship with a rational moral code. Regarding governance, Enlightenment thinkers explored the relationship between the individual and the state, developing the idea of the social contract, an implicit agreement forming the basis for society that sets forth the rights and responsibilities of individuals and the state. They also viewed the state as a tool for progress, supporting centralization and standardization. Notably, given the widespread chaos and violence stemming in large part from religious wars in the sixteenth and seventeenth centuries, most supported monarchical government and even absolute monarchy, though many called for enlightened absolutism as a means of imposing Enlightenment reforms. Ultimately, however, the thinking of absolutists such as seventeenth-century French bishop Jacques-Bénigne Bossuet, who asserted the divine right of kings as rulers enthroned by and accountable only to God, gave way to the competing concept of natural law and its corollary, natural rights.
While the Enlightenment is often dated to the eighteenth century, many scholars argue that the movement began in the mid-seventeenth century or even earlier. In either event, René Descartes, a French philosopher, mathematician, and scientist who used reason to support faith and viewed the universe in mechanistic, “clockwork” terms, was a seminal influence. Exploring the acquisition of knowledge in Discours de la méthode (Discourse on Method) (1637), he privileged subjectivity and the individual over objectivity and tradition in his search for truth, concluding Cogito, ergo sum (“I think, therefore I am”). Other major seventeenth-century influences on or manifestations of Enlightenment thinking include English mathematician and philosopher Sir Isaac Newton’s discoveries of natural laws concerning gravitation and motion; English philosopher Thomas Hobbes’s political classic Leviathan (1651), which set forth the concept of the social contract as the basis for society and posited the need for a strong sovereign to enforce the contract; French mathematician and philosopher Blaise Pascal’s Pensées (Thoughts) (1669), an unfinished work intended as a defense of Christianity; Jewish rationalist philosopher Benedictus de Spinoza’s Ethics (c. 1677), which expressed the pantheistic view that God and nature are one; and the skepticism of French philosopher Pierre Bayle, embodied in his Dictionnaire historique et critique (Historical and Critical Dictionary) (1697). Also important was English philosopher John Locke’s empirical theory of the human mind and political theories involving natural law. In “An Essay Concerning Human Understanding” (1690), Locke argued that the human mind begins as a tabula rasa, or blank slate; that all knowledge comes from sensory experience; and that changing the human environment can change society. Politically, he posited natural law as the basis for government in Two Treatises on Government (1690), argued that people are by nature free and equal, and framed the social contract as a means of furthering equality and freedom.
Subsequently, the philosophes, French philosophers active in the mid-eighteenth century, championed the tenets of the Enlightenment, embracing deism, religious tolerance, and rational progress. The most influential philosophes were Jean-Jacques Rousseau, who focused on liberty and the relationship between the individual and the state, and Voltaire (François Marie Arouet), who promoted empiricism and religious tolerance. In works such as Discours sur l’origine et les fondements de l’inégalité parmi les hommes (A Discourse on Inequality) (1754) and Le contrat social (The Social Contract) (1762), Rousseau developed the idea of the “noble savage,” a noncivilized but innately good human, and argued that the social contract should be based on rights and equality for all. Voltaire, unlike most French philosophers, rejected rationalism, insisted on verification through the senses, and advocated for the primacy of secular values, arguing in works such as Traité sur la tolérance (A Treatise on Tolerance) (1763) that the worst crimes against humanity were committed in the name of religion. Also important in the political realm was Baron de Montesquieu’s De l’esprit des lois (The Spirit of the Laws) (1748), which called for independent legislative, executive, and judicial branches in government, a separation of powers creating a system of checks and balances. Other notable philosophes included Denis Diderot and Jean le Rond d’Alembert, who spearheaded an Encyclopédie, ou dictionnaire raisonnée des sciences, des arts et des métiers (Encyclopedia) (28 vols., 1751—72) meant to secularize learning and serve as a manifesto of the philosophe movement.
Major figures associated with the Enlightenment in Britain — English, Irish, and Scottish philosophes, so to speak — included George Berkeley, Edward Gibbon, David Hume, and Adam Smith. Hume, an empiricist and skeptic, argued in An Enquiry Concerning Human Understanding (1748) that impressions (sensations or emotions) are the source of all human ideas, denied that humans can know anything with certainty, and sanctioned moral relativism. Smith, who posited the existence of an invisible, guiding hand in free markets and advocated laissez-faire economics, theorized capitalism in An Inquiry into the Nature and Causes of the Wealth of Nations (1776).
In Germany, noted Enlightenment philosophers aside from Kant included Gotthold Ephraim Lessing and Moses Mendelssohn. Lessing advocated religious tolerance in works such as his play Nathan der Weise (Nathan the Wise) (1779) and further argued in Die Erziehung des Menschengeschlechts (The Education of the Human Race) (1780) that the history of world religions showed evolving moral awareness. Mendelssohn promoted rational progress and spurred the Haskalah, or Jewish Enlightenment. In Italy, Cesare Beccaria’s Dei delitti e delle pene (On Crimes and Punishments) (1764), which opposed corporal and capital punishment and advocated incarceration as a way to protect society and rehabilitate convicts, revolutionized European penal systems. In America, leading figures such as Benjamin Franklin, Thomas Jefferson, and Thomas Paine, all deists, based the American Revolution and founding documents such as the Declaration of Independence and the Constitution on Enlightenment ideas, putting concepts such as inalienable rights, natural law, self-determination, and self-evident truths into practice. The same concepts subsequently influenced the French Revolution, which broke out in 1789 and ended following the Reign of Terror engendered by Maximilien Robespierre.