10 Fascinating Insights Into the Enlightenment Era

“Liberté, égalité, fraternité.” These three words, the iconic slogan of the French Revolution, trace their origins to the Enlightenment. This intellectual movement, which emerged in the late 17th century and continued through the 18th century, questioned long-established political and religious norms in Europe dating back to the Middle Ages.

Here are the key facts that not only highlight the movement's core principles but also dispel some widespread misunderstandings about its multifaceted—and at times contradictory—role in shaping human history.

1. The Enlightenment was not confined to France alone.

Although many of the Enlightenment’s most prominent thinkers—René Descartes, M. de Voltaire, Jean-Jacques Rousseau, and the Baron de Montesquieu—were French, the Enlightenment was far from being a uniquely French movement. Rather than emanating solely from Paris, the movement evolved independently and concurrently in various regions of Europe.

In England, economist Adam Smith, author of the influential pro-capitalist work The Wealth of Nations (1776), contributed to the movement. In North America, Benjamin Franklin and Thomas Jefferson infused Enlightenment ideals into the struggle for American independence and the establishment of democratic governance in the 1770s and ‘80s. Meanwhile, German philosopher Immanuel Kant, residing in Königsberg (now Kaliningrad), developed his categorical imperative: a set of ethical principles that applied universally, regardless of social status.

2. The Enlightenment laid the foundation for modern science.

The principles that brought Enlightenment thinkers together from various countries—rationalism, empiricism, skepticism, and subjectivism—are the same principles that continue to guide contemporary researchers and scholars today. Rationalism emphasizes that knowledge should be acquired through reason rather than emotion or faith; empiricism and skepticism encourage constant questioning of everything and everyone; and subjectivism recognizes that truth is often shaped by an individual’s perspective.

The origins of modern scientific research can be traced to early Enlightenment thinkers like Descartes, who passed away in 1650. Just as Descartes, the originator of the famous phrase cogito, ergo sum (“I think, therefore I am”), accepted a proposition as true only if it could not be disproven, modern research—whether in middle schools or universities—often involves testing a “null hypothesis,” which attempts to challenge claims that there is no significant difference between two variables.

3. The Enlightenment emerged from the Protestant Reformation and the Italian Renaissance.

Several factors contributed to the rise of the Enlightenment. Continued support from the “Sun King,” Louis XIV, who invested heavily in art and culture to elevate France’s prestige among European nations, attracted intellectuals and creatives to Paris. The Protestant Reformation, which revolted against the Roman Catholic Church and its doctrines, contested the long-held belief that monarchs drew their authority from God.

The scientific revolution of the 16th and early 17th centuries, itself an outcome of the Reformation, further fueled the Enlightenment by challenging traditional beliefs, such as the idea that Earth was the center of the solar system. Finally, the Enlightenment owes much of its existence to the Renaissance, which not only revived ancient art forms but also renewed interest in classical texts, from Plato’s dialogues to the republican philosophy of ancient Rome.

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

Civil unrest in France initially stemmed from financial difficulties: debt incurred from international conflicts like the American Revolution and King Louis XVI’s proposal to raise taxes in response. However, the way this unrest manifested was undeniably influenced by ideas promoted during the Enlightenment. The protestors were not only rebelling against their king, but against the political system he embodied.

The echoes of “liberté, égalité, fraternité” can be found in many Enlightenment works, including The Social Contract (1762) by Rousseau. Rousseau, challenging the belief held by his conservative critics that human corruption was the result of inherent flaws, argued instead that corrupt institutions distorted the fundamental goodness of humanity. He proposed that kings derived their power from the people, and if they failed to uphold this agreement, the people had the right to strip that power away.

5. The Enlightenment nearly led to a change in the French calendar.

Like with any artistic, philosophical, or political movement, there were those within the Enlightenment who wanted to push its ideals to their extreme. In France, these individuals included the Committee of Public Safety, established in 1793 to protect the Revolution from internal and external threats. Armed with the guillotine, the committee enforced policies that ranged from radical to absurd.

One of the committee's more extreme ideas was to replace Christianity with what its leader, the vengeful lawyer-turned-dictator Maximilien de Robespierre, called the “Cult of the Supreme Being,” a belief system focused on the worship of a concept of god, rather than a specific deity. Revolutionaries even altered the French calendar, instituting 10-day weeks and starting the year on September 22, all in an effort to distance time from Christian traditions.

The 11th month of the new calendar, Thermidor (lasting from July 19 to August 17), became infamous. Robespierre himself was executed on 9 Thermidor, Year II (July 27, 1794), triggering the Thermidorian Reaction, which ended the Reign of Terror and ushered in a more conservative government.

6. In an ironic twist, Emperor Napoleon Bonaparte implemented Enlightenment reforms in France.

Napoleon Bonaparte, the French emperor, arguably contributed more to the Revolution and the Enlightenment than Robespierre’s Committee of Public Safety. As an “enlightened despot,” the Corsican general wielded his absolute power to enact sweeping reforms that, under more democratic circumstances, might never have been possible.

Throughout his 15-year reign, Napoleon established a judicial branch, a central bank, and a secondary education system (the lycées). He replaced the old regime’s nepotism with a merit-based and organized bureaucracy, dismantled medieval feudalism, granted religious freedom, and ensured equality before the law through the Napoleonic Code—many aspects of which continue to influence European constitutions today.

However, in his pursuit to expand the global French Empire, Napoleon reinstated slavery in the French Caribbean in 1802 and denied equal rights to free people of color.

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

A common misconception about the Enlightenment is that it played a key role in abolishing human bondage in European colonies. Although the Enlightenment occurred just before several European countries, starting with Denmark in 1803, outlawed slavery, the link between these two events remains unclear.

The reality is that, while some Enlightenment thinkers opposed slavery, others actively defended it. Philosophers like Rousseau and Locke argued that human rights transcended race, making slavery both unnatural and indefensible. However, many of their contemporaries, including several U.S. founding fathers and even Kant, endorsed white supremacy and subscribed to the erroneous notion of a racial hierarchy.

8. The Enlightenment inspired the American Revolution.

Considering France’s alliance with the 13 American colonies during the Revolutionary War, it’s no surprise that the Enlightenment greatly influenced the formation of the U.S. government. This influence is evident in the 1776 Declaration of Independence, which asserts that life, liberty, and the pursuit of happiness are fundamental human rights.  

These rights, along with the concept of the separation of powers as described in Montesquieu’s 1748 work The Spirit of the Laws, were further solidified in the U.S. Constitution. Anyone studying American history will also note that, despite this Enlightenment inspiration, the early U.S. government adopted contradictory views on racial equality, as many elite landowners lauded Rousseau’s Social Contract while failing to extend its principles to non-white individuals. 

9. The Enlightenment gave rise to the novel.

Before the 1700s, fiction was primarily expressed through poetry and theatre. While the first European novel, Miguel de Cervantes’s 1605 masterpiece Don Quixote, predates the Enlightenment by over a century, Enlightenment thinkers helped shape this emerging genre into the captivating literary form we recognize today.

Many features that define the modern novel—such as a focus on personal experience, varying levels of realism and social criticism, and an emphasis on dialogue—originated during the Enlightenment. A quintessential example of an Enlightenment-era novel is Candide by Voltaire. Published in 1759, this tale of a young, idealistic man searching for the best way to live his life inspired countless generations of novelists worldwide.

10. The Enlightenment was not merely a period of reason.

A common misconception about the Enlightenment is that it prioritized logic and reason at the expense of emotion and passion. According to this view, the cool, calculated rationality of the Enlightenment eventually gave rise to Romanticism, a movement that celebrated values such as ambition, sentiment, and the sublime beauty of nature, all of which the Enlightenment supposedly overlooked.

This interpretation, though appealing and simple, is not entirely accurate. As Henry Martyn Lloyd, an honorary research fellow in philosophy at the University of Queensland, highlights in an article for Aeon magazine, the Enlightenment was more diverse and nuanced than often credited, with many thinkers recognizing the importance of imagination, playfulness, and embodiment. After all, Descartes’ famous declaration “I think, therefore I am” linked reflection to the very act of simply existing in the world.