The Enlightenment took advantage of new forms of intellectual exchange. Enlightenment thinkers like David Hume (1711–1776) railed against the exclusivity of earlier generations and insisted on bringing knowledge out of the pedantic world of the closeted learned to the sociable world of polite conversation in academies, debating societies, salons, and coffeehouses. Along with the expansion of the sphere of oral communication went a similar expansion of readership and print culture. In this period books became smaller, cheaper, and therefore more accessible. This time witnessed the birth of the periodical press, of newspapers and magazines. Changes in print production went along with changes in how readers related to print. Gone were the days of laborious reading; instead expanding literacy, particularly among middle-class men, meant that expanding audiences read pamphlets, essays, novels, and newspapers in their leisure time.

The sixteenth and seventeenth centuries saw European thinkers challenge inherited ideas about the physical universe. Medieval thinkers had built elaborate cosmological systems upon classical, and particularly Aristotelian, foundations. But in many fields, such as physics, applied mathematics, and especially astronomy, new discoveries and explanations put forward by Nicolaus Copernicus (1473–1543), Galileo Galilei (1564–1642), and Sir Isaac Newton (1642–1727), among others, challenged the picture of a finite, Earth-centered universe and replaced it with a potentially infinite universe and a sun-centered system. Explanations of the physical universe thus increasingly presented it as analogous to a mechanism, governed by rational, mathematically expressible rules, which a divine power may have created but with which it did not need to interfere.

Education is a progressive discovery of our own ignorance.

John Dryden (1631–1700)

This shift to mechanistic explanations was also apparent in moral philosophy. Seventeenth-century thinkers like William Harvey (1578–1657), Thomas Hobbes (1588–1679), René Descartes (1596–1650), and John Locke (1632–1704) developed new medical and psychological theories to account for human movement, behavior, feeling, and thinking as governed by mechanical principles. The philosophes then developed economic, social, and political theories that challenged the belief in a divinely instituted and intuitively recognizable order. Enlightenment thinkers viewed human nature in terms of a morally neutral tabula rasa, or blank slate, that could be molded in various ways. They applied the idea of a social tabula rasa, or state of nature, to explain how civil society might have emerged and ought to be governed. Many Enlightenment thinkers, such as Hobbes, the Marquis d’Argenson (1694–1757), Montesquieu (1689–1755), and Jean-Jacques Rousseau (1712–1778), argued that political stability could be guaranteed by organizing society as a machine in which each component worked in harmony with the rest. Still others, like Locke in his The Second Treatise of Government (1689), used the idea of a state of nature to define the boundaries of state power in guaranteeing political stability.

During the seventeenth century, European intellectuals quarreled over whether contemporary “modern” European thinkers had surpassed their “ancient” Greek and Roman counterparts, and this debate gave rise to the Enlightenment belief that better ways of thinking and behaving had emerged in recent decades. The sense of modern improvements led to a faith among the philosophes that the new ideas and methods would guarantee indefinite progress in politics, society, and the arts and sciences. The philosophes took up the cause of improving their social and natural surroundings through experiment and reform. Societies and academies, such as the English Royal Society, emerged in which innovative ideas and techniques were presented, debated, and recommended. From agricultural techniques to zoological taxonomies, progressive reform was an important Enlightenment ideal associated with another Enlightenment principle: utility. Hume (1902, 183) wrote that “public utility is the sole origin of justice.” In their emphasis upon principles of progress and utility, most Enlightenment thinkers were the heirs to the “moderns” in the quarrel of the ancients and moderns.

But the Enlightenment cannot be equated easily with the rise of modernity if we understand modernity to mean atheism and democracy. As often happens with any movement critical of established institutions or ideas, definitions of the Enlightenment have been constructed as much by its enemies as by the philosophes themselves. An appreciation of the Enlightenment must therefore go beyond commonplace definitions that tend to see it as simply challenging the authority of church and state, of Christianity and absolute monarchy. Indeed, with few exceptions, Enlightenment thinkers were defenders of both.

The Enlightenment’s religious outlook was built partly upon the ideas of certain dissenting Protestant sects, such as Socinians (who denied the divinity of Christ, and consequently the Trinity) and Arians (who believed that the Son was not of the same substance as the father), and also partly upon the skeptical and humanistic traditions within Roman Catholicism. In fact, the very term enlightenment had already been used by Christians to designate divine inspiration. But many Enlightenment thinkers reacted to what they criticized as the “enthusiasm” of religious dogmatists and the “fanaticism” of religious wars, such as the French Wars of Religion (1559–1598), the English Civil Wars (1638–1660) or the Thirty Years War (1618–1648). They emphasized the need rationally to reexamine the foundations of beliefs. These individuals insisted that religion ought to agree with reason and that any belief not derived from observation of the world or from human reason ought to be rejected. These thoughts encouraged the tolerance and rationalism that gave rise to the ideas of deists like Voltaire (1694–1778), who argued for a pared-down, “reasonable” Christianity emptied of its dogma and ritual, as well as those of atheists like Hume and the Baron d’Holbach (1723–1789).

Hume wanted to expand knowledge of the pedantic world into the sociable world of polite conversation in academies, debating societies, salons, and coffeehouses. New York Public Library.

The Enlightenment’s political outlook similarly mixed continuity with the past and a critical perspective on traditions. Although their enemies often accused the philosophes of corroding political order and the established monarchy, most philosophes actually favored monarchy. George III in Great Britain, Louis XV and Louis XVI in France, Frederick the Great in Prussia, Joseph II in Austria, and Catherine the Great in Russia all gave support to and were supported by Enlightenment thinkers. Influenced by the Enlightenment principle of maximizing utility, these monarchs tried to institute reforms in their kingdoms. Thus Enlightenment thinkers like Voltaire actually advocated a form of “enlightened despotism,” or the rule of a single sovereign with absolute power to reform society. Two things that Enlightenment political philosophes tended to oppose were what they called “Oriental despotism,” the kind of arbitrary rule they associated with Islamic states, and the customary privileges enjoyed by certain groups, like aristocrats and guilds, which they saw as inefficient and inequitable.

Although the Enlightenment was almost exclusively a European phenomenon, the wider world played a key role in the development of Enlightenment thought. Descriptions of previously unknown species of animals discovered in distant lands led natural historians, such as Carolus Linnaeus (1707–1778), to develop new taxonomical systems that could effectively organize the growing mass of information regarding plants and animals. Discoveries of fossilized plants and animals also led many to abandon the practice of interpreting scriptural accounts of the world’s creation literally. Instead philosophes like Georges-Louis Leclerc de Buffon (1707–1788) argued that the Earth was formed and transformed at extremely slow evolutionary rates and as the result of natural occurrences such as volcanic activity and tides.

European encounters with non-Europeans and their languages, religions, and political practices also stimulated Enlightenment thinkers in many ways. Philologists such as Sir William Jones (1746–1794), who recognized the affinities between Persian and European languages, set the stage for nineteenth-century comparative grammarians. Jesuit missionaries in China, impressed with the virtue of the people they encountered, emphasized parallels between Christian and Confucian beliefs, and many Enlightenment thinkers, such as Matthew Tindal (1653–1733) and Gottfried Wilhelm Leibniz (1646–1716), pointed to China in arguing against the need for revelation, and for the idea that the tenets of natural religion were apparent to all reasonable and observant people. The Scottish thinker Henry Home (1696–1782), noting the radical physical differences between peoples around the world, argued for the polygenetic origins of human races, an argument that contradicted scriptural accounts.

The tendency of Enlightenment thinkers increasingly to compare their own society to those of recently discovered and distant peoples challenged traditional notions in many other ways. Locke, for example, in his Second Treatise on Government (1690), noted that “in the beginning, all the world was America” (Locke 1993, 285). Though very few had traveled outside Europe, Enlightenment thinkers frequently used descriptions of distant cultures to comment on their own countries. One of the commonplaces of the Enlightenment was the image of the American Indian, and later of the Pacific Islander, as existing in a state of nature without literature, religion, laws, or political and social distinctions. The French aristocrat Louis Armand de Lahontan (1666–1716), for example, popularized the figure of the American Indian as living in this enviable state through the publication of fictional dialogues between a Huron and himself. In these dialogues, the Huron gets the better of his European interlocutor on such subjects as marriage, religion, and jurisprudence. Lahontan’s work was discussed by important European thinkers such as Leibniz and influenced ideas of natural law and natural religion. Lahontan’s A Conference or Dialogue between the Author and Adario, a Noted Man among the Savages (1703), and other works like Montesquieu’s Persian Letters (1721), Voltaire’s Ingenuous (1767), and Oliver Goldsmith’s (1730–1774) Citizen of the World (1762), popularized the Enlightenment genre of the imaginary traveler from a distant land who comments critically upon European customs. Indeed, this was one of the most important vehicles through which European audiences imagined non-Europeans and criticized customs within their own society.

The Enlightenment’s encounter with non-Western societies also promoted the rise of what we now call the social sciences. Sociology, ethnography, anthropology, psychology, economics, political economy, and even literary criticism all grew out of the Enlightenment. Enlightenment historians studied how each human society followed a definite and, for most philosophes, progressive development from a hypothetical state of nature to civilization. This “conjectural history” implied definite hierarchies of cultures, and the Enlightenment was an important period in the development of cultural particularism, which fed into the nationalist and racialist ideologies of the nineteenth century.

But since the Enlightenment thinkers saw differences between peoples as cultural, historical, or environmental rather than racial, they tended to see human nature and dignity as shared in common among all peoples. This view played a large role in the development of Enlightenment cosmopolitanism, the idea that the philosophe is a citizen of the world more than of any nation-state with its accidental traditions. Another important implication of this emphasis on a shared human nature was that many Enlightenment thinkers, such as Diderot and the Abbé Raynal (1713–1796), condemned slavery as an immoral and inhumane practice and played a role in the development of the abolitionist sentiment.

One of the perennial questions surrounding the Enlightenment is the extent of its influence, particularly on the political and social revolutions in Europe and in European colonies in the Americas. As noted above, most Enlightenment thinkers did not advocate either political revolution or republicanism. In fact, in some ways, the very concept of the Enlightenment as a coherent movement, critical of established political institutions and ideas, was created as much by revolutionaries seeking retrospectively to justify their actions intellectually as by the ideas of the philosophes themselves or the assertions of their enemies. There can be no question, however, that certain American revolutionaries, like Thomas Jefferson (1743–1826) and Thomas Paine (1737–1809), were influenced by Enlightenment ideas and that Rousseau in particular had a tremendous impact on the course of the French Revolution. Simón Bolívar (1783–1830), the “liberator” of South America, learned from his tutor about Rousseau and Voltaire, and while traveling in Europe he absorbed Enlightenment ideas from such thinkers as Alexander von Humboldt (1769–1859). The idea of a written constitution, of freedom from arbitrary and unjust customs, of equality before the law, and, to some extent, of checks and balances within government were all concepts advanced by Enlightenment thinkers. In these ways, as well as others, many of which are noted above, the Enlightenment contributed much to the emergence of the modern world.

Darwin, Charles; Descartes, René; Mathematics; Science—Overview; Scientific Revolution