How the Enlightenment Worked

The publication of Isaac Newton's "Principia" effectively started the Enlightenment.
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As the story goes, an apple fell on Isaac Newton's head one day and knocked some sense into him. After hammering out the finer points of a new kind of arithmetic called calculus, Newton decoded the force in the universe that binds everything together. No longer did a supernatural power hold things in place on Earth -- it was simply a string of numbers and operations signs that equaled "g." His 1687 masterpiece, "The Mathematical Principles of the Universe" (known simply as "Principia"), detailed the laws of gravity, transformed the scientific and intellectual communities and ushered in the age of Enlightenment.

Textbook definitions of the Enlightenment generally focus on a group of French men, the philosophes, rather than Newton. Often framed as a philosophical movement, it's easy to oversimplify the Enlightenment as an extended period of navel-gazing. But the landmark ideas that Voltaire, Diderot, Rousseau and the others debated and scribbled down didn't spring forth from a void. They were first ignited by scientific breakthroughs and historical events that fundamentally altered their concept of the world.


Prior to Newton's "Principia," Western Europe had already undergone intense political and religious transformation. The Thirty Years War, which lasted from 1618 to 1648 dismantled the Holy Roman Empire and left France as the most powerful stronghold. The Protestant Reformation, launched in 1517, challenged the principles and authority of the Roman Catholic Church. International trade and exploration fostered cultural and academic exchange. In short, the world was expanding as nations grew smaller.

Newton's laws of gravity connect our world in a very real sense. Without them, life on Earth would be a floating mass of chaos. In a way, Enlightenment philosophers and scholars shared the same goal as Newton -- to mine progress out of the chaos of human civilization. From the philosophes in France to Adam Smith in Scotland and Immanuel Kant in Germany, academics across various disciplines applied their reasoning minds to solve the persistent problems of the age. Then, Enlightenment thinking was put into action in two of modern history's most significant social experiments: the American and French Revolutions. Those events tested the boundaries and strength of Enlightenment principles and came out with radically different results.

But before Newton's "Principia" sparked the intellectual sea change, the first flickers of the Enlightenment began with the two R's: the Renaissance and Reformation.


The Light Flickers: Roots of the Enlightenment

The Renaissance and Protestant Reformation helped fuel the Enlightenment.
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During the Dark Ages (A.D. 500 to 1100), scholarship languished in Western Europe. The Holy Roman Empire, which began officially in 962 with the coronation of Otto I, was dominated by feudalism, and the peasant masses had little access to education. As dictated by the Roman Catholic Church, Latin was the dominant language, and monasteries and abbeys were the centers of academic life. That setup left scant room for intellectual advancement.

But beginning in the 13th century, the tide began to change. A revival of interest in classical Greek and Roman texts ignited a new curiosity about the physical world and man's place in it. While studying at the University of Naples, a Dominican monk named Thomas Aquinas got his hands on the texts of Aristotle, which had been translated recently into Latin [source: McInerny and O'Callaghan]. Those readings inspired Aquinas' theory of scholasticism, or the study of nature as a means of explaining theology. Another monk, Roger Bacon, also read the Aristotelian translation in the middle of the 13th century. From the Greek philosopher, Bacon devised the notion of studying the physical world as a form of piety, since it focused on God's creation. These two ideas, while conceived under the supervision of the Roman Catholic Church, opened up a space for the innovation and curiosity that culminated 400 years later in the Scientific Revolution.


The resurgence of interest in classical writings spread beyond monasteries and fueled the Renaissance movement in the 14th century. Leonardo Bruni, in the same school of thought as Petrarch, revitalized the classical idea of humanism [source: McKay et al]. Echoed throughout the Enlightenment, humanism emphasized the study of humans and their accomplishments, rather than looking solely to God and sacred texts.

Then, the invention of the printing press by Johan Gutenberg in 1438 provided access to literacy for the masses. People began to shy away from Latin translations, relying on their own native tongues for printing. The press also facilitated the Protestant Reformation. In 1517, Martin Luther nailed the 95 Theses to the door of the Wittenberg Church in Germany, signaling the start of the Protestant branch of Christianity. It, combined with the Thirty Years War, would shake the foundation of the Roman Catholic Church in Western Europe. Heading into the 18th century, the bedrocks of society -- religion, feudalism, education -- had been totally transformed.


The Copernican Crisis: Scientific Revolution and the Church

Copernicus' heliocentric model of the universe attracted criticism from the church.
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Referred to as natural philosophy, science in the Middle Ages intertwined closely with religion. The church adhered to Aristotle's writings about the structure of the universe since it complemented religious dogma. The Greek philosopher's geocentric universe was composed of 10 separate crystal spheres. Beyond the tenth sphere laid God and heaven [source: McKay, Bennett and Buckler].

One outcome of the Renaissance was a renewed interest in astronomy, and that star-gazing would inadvertently contradict the church's conception of the cosmos. Nicolaus Copernicus shattered Aristotle's theory of the geocentricism when he proposed that planets revolve around the sun in 1543. Copernicus' theory discarded Aristotle's crystal spheres and enlarged the universe to infinite proportions. Though a Christian himself, Copernicus effectively displaced God and heaven and stripped man's central role in the physical realm, which attracted intense criticism from both Protestants and Roman Catholics.


The divorce between science and the church continued in 1609. Johan Kepler, former assistant to astronomer Tycho Brahe, calculated that the planets orbit the sun in an elliptical, not circular, pattern. This also chafed against religious symbolism that upheld the circle as a sign of perfection. Around this time, in the early 1600s, empirical scholar Galileo Galilei was perfecting his telescope. In 1633, the Roman Inquisition charged the astronomer with heresy for his theory that the Earth rotates on its axis, and he eventually recanted.

Francis Bacon and Rene Descartes constructed a philosophical backbone for these scientific breakthroughs. Bacon questioned the mind's ability to solve the mysteries of the natural world on its own. He concluded that experimentation was a necessary component of scientific study and created the scientific method, which was publicized in 1620. Most famous for asserting "I think, therefore, I am," Descartes separated the universe into mind and matter. Cartesian dualism, as it became known, offered an innovative perspective on the individual components in the physical world.

Synthesizing the geometry, physics and astronomy from the previous generation, Isaac Newton outlined the three laws of gravity in the 1687 publication of "Principia." From there, Enlightenment intellectuals spanning the arts and sciences would look to Newton as champion of the human mind to answer the burning questions of existence -- rather than church ideology. Ironically, Newton and his contemporaries were devoutly Christian. Descartes, for instance, attempted to reason his way to explain the existence of God. Though the church didn't heartily embrace their discoveries, the scholars didn't set out to dismantle accepted teachings. That would soon change with the rise of the French philosophes.


Starting With a Clean Slate: The Enlightenment Begins

Voltaire was the leading philosophe of the Enlightenment.
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People often think of the Enlightenment as a French phenomenon. France emerged the victor in the Thirty Years War, and it was recognized as the international center for learning in the 18th century [source: Carey]. However, the ideological roots of the Enlightenment start in England thanks, in large part, to its more liberal religious environment. A year after "Principia," the 1688 Glorious Revolution enhanced the power of the Parliament and put the first Protestant monarchy of William III and Mary on the English throne. Soon after, in 1690, John Locke published "An Essay Concerning Human Understanding."

Locke's treatise posited a blank state of the mind at birth, which he referred to as the tabula rasa. Humans' minds, according to Locke, are shaped solely by experience and education, rather than innate feelings and preordained character traits. A certain French intellect named Francois-Marie Arouet devoured Newton's and Locke's writings after being exiled to England from 1726 to 1729 for openly criticizing the French monarchy. Arouet would eventually go by the nom de plume Voltaire.


When Voltaire returned to France enlivened by these fresh Enlightenment ideals, he fanned the flame quickly. In 18th-century France, salons facilitated intellectual exchange. Organized mostly by aristocratic women and held in their homes, salons served as meeting places for scholars and wealthy laymen to discuss philosophy, politics, religion, or whatever other topics simmered in the academic sphere. These forums provided necessary safe havens because Louis XIV's absolutism instituted harsh censorship and punished detractors.

Some of the most prominent salon members were the philosophes, including Voltaire, Montesquieu, Diderot and Rousseau who valued rationalism as the key to progress. Voltaire reviled the establishment of the Church and questioned the monarchy's absolutism, but didn't necessarily espouse democracy. Instead, he considered the middle and lower classes "very rarely worthy to govern themselves." Conversely, Montesquieu, in his 1748 "Spirit of the Laws," advocated for the separation of powers in the government, and Rousseau and Diderot stridently attacked the influential position of the wealthy [source: Cranston].

In addition to critiquing government, the philosophes also decried the political authority of the church. In place of Catholicism or Protestantism, many Enlightenment thinkers, including the American Founding Fathers, were deists. In its simplest form, deist orthodoxy upheld a clockmaker God who created the world, set things in motion, then withdrew from human involvement. It was easier for intellectuals to rationalize, without fully abandoning religious faith.


The Enlightenment Outside of France

Author of "Wealth of Nations," Adam Smith.
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The Enlightenment didn't leave England with Voltaire when he returned to France in 1729. However, the manifestation of the Enlightenment differed from place to place. In France, the aristocracy patronized the arts above all. There, literature flourished with seminal works including Voltaire's "Candide" and Diderot's multivolume "Encyclopedia." England and Scotland, on the other hand, were relatively liberal due to the shift from Catholicism to Protestantism and the rising middle class [source: Gardiner]. That environment promoted advancements in the sciences and economics.

Adam Smith from Scotland published "The Wealth of Nations" in 1776, which laid the groundwork for modern capitalism. Recognizing the power of competition in the marketplace, Smith theorized that the "invisible hand" would guide the economy without the need of government interference. Another Scottish philosopher, David Hume, was referred to as a geographer of human reason. Ever the skeptic, Hume stressed relying only on absolute truths like those found in mathematics as the basis for reason [source: Gay]. Founding Fathers, including Thomas Jefferson and John Adams, practiced this skeptical moderation Hume advocated.


Enlightenment ideas of social and political reformation even trickled from the French salons and English coffeehouses to some of the leaders in western Europe. Catharine the Great, empress of Russia, corresponded with the philosophes and fancied herself as enlightened. She unsuccessfully attempted to reform Russian law based on Montesquieu's "Spirit of the Laws" [source: Gay]. Frederick the Great of Prussia invited Voltaire to take up residence in the royal court, to which the philosophe accepted.

Frederick the Great had Immanuel Kant to thank for his status as an Enlightened despot. Kant hailed the freedom of the press and religious tolerance that he sponsored. The German philosopher, best known for his motto "dare to know," remains one of the most celebrated intellects from the period. A scholar of metaphysics, or the study of human existence, Kant believed that morality had to exist alongside rationality dubbed the categorical imperative [source: Johnson]. This later served as the philosophical foundation of cultural relativism.

By the late 1700s, the political situations in France and the American colonies had intensified. In France, the populace under Louis XVI and Marie Antoinette was growing uneasy from the rising debt. Across the Atlantic, the colonies in North America were jostling for independence. Enlightenment ideology would soon be put into action.


Enlightenment in Action: American and French Revolutions

Robespierre, heading to the guillotine, was influenced by Rousseau.
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The American Revolution rebelled against monarchy and the institution of the church, backed by Enlightenment theories. A proliferation of pamphlets and essays, including Thomas Paine's "Common Sense," publicized the movement for independence in true Enlightenment fashion. Thomas Jefferson, Alexander Hamilton, Benjamin Franklin and other framers of the Constitution adhered to the philosophies of rationalism over religion, skepticism over belief and democracy over absolutism. Liberty through the separation of powers woven into the founding documents reflects Montesquieu in particular [source: Modern History Sourcebook].

Perhaps because it happened away from Europe on a real tabula rasa, the American Revolution succeeded. The events that happened in France a decade later didn't turn out so well. On July 14, 1789, the newly formed French National Assembly stormed the Bastille and started a revolution. The reaction in the United States was mixed. Some Americans saw it as a European reflection of their own struggle for nationhood; others eyed the coup with great concern [source: Staloff].


The writings of Rousseau deeply impacted Robespierre, the leader of the radical Jacobin Party [source: Halsall]. According to the philosophe, people should abide by the social contract of general will tempered by sovereignty. From there, it's up to the government to bestow liberties unto the people. An extreme manifestation of Rousseau's social contract emerged as the Revolution spiraled out of control. Consider, for instance, the Reign of Terror when Jacobins seized control. The general will had spoken at the Bastille storming, and it was up to Robespierre to administer freedoms. From 1793 to 1794, the Committee of Public Safety killed off thousands, including Marie Antoinette -- all in the name of liberty.

After the dust settled on the political dramas at the end of the 18th century, the extreme rationalism and skepticism espoused by the Enlightenment had reached a limit. Some people didn't wish to peer at human nature through the microscope of reason. Romanticism arrived as the antidote. The era that started with Newton's "Principia" closed with the publication of Wordsworth and Coleridge's "Lyrical Ballads" in 1798. In it, the poets wrote that "not by the intellect, but the deep power of joy, we see into the life of things" [source: Wordsworth and Coleridge].

Voltaire would've shuddered at the thought.


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More Great Links

  • Carey, Toni Vogel. "The Enlightenments." Philosophy Now. March/April 2003.
  • Carrell, Jennifer Lee. "Newton's Vice." Smithsonian. December 2000. (Feb. 27, 2009)
  • Cranston, Maurice. "Philosophers and Pamphleteers." Oxford University Press. 1986.
  • Gardiner, T. Edward. "The Enlightenment." History Magazine. August/September 2004.
  • Gay, Peter. "Age of Enlightenment." TIME-LIFE Books. 1966.
  • Hampson, Norman. "Cultural History of the Enlightenment." Pantheon Books. 1968. Johnson, Robert. "Kant's Moral Philosophy." Stanford Encyclopedia of Philosophy. Feb. 23, 2004. (Feb. 27, 2009)
  • Klein, Juergen. "Francis Bacon." Stanford Encyclopedia of Philosophy. Dec. 29, 2003. (Feb. 27, 2009)
  • McInerny, Ralph and O'Callaghan, John. "Saint Thomas Aquinas." Stanford Encyclopedia of Philosophy. July 12, 1999. (Feb. 27, 2009)
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  • Modern History Sourcebook. "Salon Life." August 1997. (Feb. 27, 2009)
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