10 Illuminating Facts About the Enlightenment

The period of scientific, artistic, and political revolutions isn’t known as the “Age of Reason” for nothing.
Jacques Louis David’s portrait of Antoine and Marie Anne Lavoisier. Antoine Lavoisier was a chemist during the Enlightenment who was later beheaded.
Jacques Louis David’s portrait of Antoine and Marie Anne Lavoisier. Antoine Lavoisier was a chemist during the Enlightenment who was later beheaded. / Metropolitan Museum of Art // Public Domain

Liberté, égalité, fraternité.” All three parts of this slogan, the famous battle cry of the French Revolution, have their roots in the Enlightenment. An intellectual movement that coalesced during the late 17th century and lasted through the late 18th century, the Enlightenment challenged political and religious conventions that had been entrenched in Europe since the beginning of the Middle Ages.

Here are the facts to not only outline the movement’s core beliefs, but also clear up some common misconceptions about its complicated—and at times contradictory—impact on the course of human history.

1. The Enlightenment wasn’t restricted to France.

Despite many of the Enlightenment’s most influential thinkers—René Descartes, M. de Voltaire, Jean-Jacques Rousseau, the Baron de Montesquieu—being French, the Enlightenment was by no means a uniquely French phenomenon. Instead of radiating outward from Paris, the movement developed simultaneously and at times autonomously in different parts of Europe.

In England, there was economist Adam Smith, author of the pro-capitalist text The Wealth of Nations (1776). In North America, Benjamin Franklin and Thomas Jefferson channeled enlightened ideals into the fight for American independence and democratic rule in the 1770s and ‘80s. And from his lifelong home in Königsberg (now Kaliningrad), German philosopher Immanuel Kant formulated his categorical imperative: ethical rules that applied to every member of society, be they lord or lowborn.

2. The Enlightenment gave us modern science.

Joseph Wright of Derby’s ‘A Philosopher Lecturing on the Orrery’
Joseph Wright’s ‘A Philosopher Lecturing on the Orrery,’ showing a model of the solar system with the sun (represented by a lamp) at its center. / Derby Museum and Art Gallery, Wikimedia Commons // Public Domain

The principles that united Enlightenment thinkers from different countries—rationalism, empiricism, skepticism, and subjectivism—are the same principles that guide contemporary researchers and academics today. Rationalism holds that knowledge should be gained through reason rather than emotion or faith; empiricism and skepticism are reminders to question everything and everyone; and subjectivism is an acknowledgement that truth is often dependent on one’s own viewpoint.

The nature of modern-day scientific research can be traced back to proto-Enlightenment philosophers like Descartes, who died in 1650. Just as Descartes—who coined the iconic phrase cogito, ergo sum (“I think, therefore I am”)—accepted propositions as true only if he was unable to prove them false. Today, research projects from middle schools to universities revolve around the investigation of a “null hypothesis,” which attempts to disprove a hypothesis that claims there’s no difference between two variables.

3. The Enlightenment grew out of the Protestant Reformation and Italian Renaissance.

The Enlightenment has several different causes. Sustained funding from the “Sun King,” Louis XIV, who invested in art and culture to impress other European nations, brought creatives and intellectuals to Paris. The Protestant Reformation, a revolt against the Roman Catholic Church and its doctrines, objected to the age-old notion that monarchs derived their earthly authority from God.

The scientific revolution of the 16th and early 17th centuries, itself a product of the Reformation, also contributed to the Enlightenment through discoveries that refuted commonly held beliefs, like Earth being the center of the solar system. Last but not least, the Enlightenment owes its existence to the Renaissance, which, in addition to renewing long-dead art styles, revived interest in classical texts from Plato’s dialogues to the republican philosophy of ancient Rome.

4. The Enlightenment was not the only cause of the French Revolution.

Nicolas Henri Jeaurat de Bertry’s allegory of the French Revolution (1794)
Nicolas Henri Jeaurat de Bertry’s allegory of the French Revolution with a portrait of Rousseau / Musée Carnvalet, Wikimedia Commons // Public Domain

Technically, civil unrest in France started over monetary issues: debt accumulated by international conflicts like the American Revolution and King Louis XVI’s plan to increase taxes in response. The shape this unrest took, however, was undoubtedly the result of ideas introduced during the Enlightenment. Protestors were not merely rebelling against their king, but against the political system he represented.

Echoes of “liberté, égalité, fraternité” can be read in many Enlightenment texts, including The Social Contract (1762) by Rousseau. Arguing that flawed institutions corrupted the inherent goodness of humanity, and not the other way around (as his conservative opponents believed), Rousseau proposed that kings received their power from the people, and that, if they did not honor this relationship, the people were within their rights to take that power away.

5. The Enlightenment almost changed the French calendar.

As in every artistic, philosophical, or political movement, there were proponents of the Enlightenment who wished to carry its principles to their extreme. In France, such proponents included the Committee of Public Safety, created in 1793 to defend the Revolution from domestic and foreign foes. Backed by the blade of the guillotine, it implemented policies that ranged from radical to nonsensical.

Among other things, the committee sought to replace Christianity with what its leader, the vindictive lawyer-turned-tyrant Maximilien de Robespierre, referred to as the “Cult of the Supreme Being,” an organization dedicated to the worship of the idea of god, rather than a specific deity. Revolutionaries even changed the French calendar, introducing weeks that lasted for 10 days instead of seven and a year that began on a date corresponding to September 22, all to avoid marking time with Christian associations.

Thermidor, the new name for the calendar’s 11th month (lasting from July 19 to August 17), is particularly infamous. Robespierre himself was executed on 9 Thermidor, Year II (a.k.a. July 27, 1794), kicking off the Thermidorian Reaction, which ended the Reign of Terror and implemented a more conservative government.

6. Ironically, Emperor Napoleon Bonaparte established Enlightenment reforms in France.

Emperor of France Napoleon Bonaparte in his coronation robes, painted by François Gérard.
Emperor of France Napoleon Bonaparte in his coronation robes, painted by François Gérard. / Musée National du Château de Fontainebleau, Wikimedia Commons // Public Domain

The French emperor Napoleon Bonaparte arguably did more for the Revolution and the Enlightenment than Robespierre’s Committee of Public Safety. Acting as an “enlightened despot,” the Corsican general used his absolute power to pass sweeping reforms that, under more democratic circumstances, might never have seen the light of day.

During his 15 years on the throne, Napoleon gave France a judicial branch, a central bank, and a secondary schooling system (the lycées). He replaced the nepotism of the ancien régime with a meritocratic and organized bureaucracy, abolished medieval feudalism, implemented religious freedom, and introduced equality before the law via his Napoleonic Code, aspects of which remain embedded in European constitutions to this day.

Yet, as a part of his quest to expand the global French Empire, Napoleon also restored slavery in the French Caribbean in 1802 and denied equal rights to free people of color.

7. The Enlightenment did not put an end to slavery.

A common misconception about the Enlightenment is that the movement helped put an end to human bondage in the European colonies. Although the Enlightenment took place shortly before several European nations abolished slavery, starting with Denmark in 1803, the connection between the two historical events remains ambiguous.

The truth is that, while some enlightened thinkers opposed slavery, others went out of their way promoting it. Thinkers like Rousseau and Locke argued the unalienable rights of man transcended skin color, rendering slavery unnatural and inexcusable, but many of their contemporaries advocated for white supremacy. These included several U.S. founding fathers, as well as Kant, who subscribed to the false idea of a hierarchy of races.

8. The Enlightenment inspired the American Revolution.

‘The Siege Of Yorktown’ by Louis-Charles-Auguste Couder
‘The Siege Of Yorktown’ by Auguste Couder depicts the defeat of the British by George Washington's and the Comte de Rochambeau’s combined forces. / Heritage Images/GettyImages

Given that France allied itself with the 13 American colonies in the Revolutionary War, it should come as no surprise that the Enlightenment had a profound impact on the design of the U.S. government. This influence is present in the 1776 Declaration of Independence, which identifies life, liberty, and the pursuit of happiness as basic human rights.  

These rights, along with the separation of powers as outlined by Montesquieu’s 1748 text The Spirit of the Laws, were further enshrined in the U.S. Constitution. Any student of American history will also recognize that the fledgling country adopted the Enlightenment’s contradictory attitudes towards racial equality, with many landowning elite praising Rousseau’s Social Contract while failing to apply its teachings to anyone who wasn’t white. 

9. The Enlightenment gave rise to the novel.

Before the 1700s, fiction generally existed in the form of poetry and theatre. Although the first European novel, Miguel de Cervantes’s 1605 classic Don Quixote, predates the Enlightenment by more than a century, enlightened thinkers helped mold this underdeveloped medium into the engrossing literary form we know and love today.

Several of the characteristics that define the modern novel—an interest in individual experience, varying degrees of realism and social critique, and emphasis on dialogue—stem from the Enlightenment. A prime example of a prototypical enlightened novel is Candide by Voltaire. Published in 1759, the story about a young, naïve, and passionate man trying to figure out the best way to live life went on to inspire generations of novelists across the world.

10. The Enlightenment was not just an age of reason.

Another popular misconception about the Enlightenment is that the movement accepted logic and reason at the expense of passion and emotion. According to this narrative, the cold and calculated rationality of the Enlightenment eventually gave way to Romanticism, a movement that valued everything the Enlightenment took for granted, including ambition, sentiment, and the sublime beauty of nature.

It’s an appealing and easily digestible interpretation of the past, but not entirely correct. As Henry Martyn Lloyd, an honorary research fellow in philosophy at the University of Queensland, points out in an article for Aeon magazine, the Enlightenment was more diverse and complex than people give it credit for, with many thinkers recognizing the value and benefits of playfulness, imagination, and embodiment. Descartes, through his declaration “I think, therefore I am,” did, after all, connect reflection to the act of simply being in the world.