Between the late seventeenth and late eighteenth centuries, there was a period of rapid intellectual change that became known as the Enlightenment. Thinkers, writers, artists, political leaders, and many ordinary people drove this cultural and intellectual movement. They believed they were shining the “light” of reason on the natural and human worlds. In 1784, German philosopher Immanuel Kant wrote that an “enlightened” understanding should start with the command: “Dare to know!”

The Enlightenment transformed European intellectual life and had social, economic, and political consequences across the globe. To understand the role of the Enlightenment in world history, we need to look both at its ideas and social setting. Enlightenment ideas did not just appear all at once, but rather emerged from ongoing discussions among many people. Enlightenment thinkers, writers, and artists—known as philosophes—were particularly active in Europe and European settler colonies. They were also connected to networks that moved around the globe. Goods, information, and people moved across oceans, spreading Enlightenment ideas. This enabled Enlightenment ideas to inspire revolutions.

What was so enlightening about the Enlightenment?

The Enlightenment started as a scientific and intellectual movement. However, it soon became a political movement, with economic and cultural significance. Not all Enlightenment thinkers agreed about everything, but they were devoted to lively study and conversation. They met at public lectures, salons, coffeehouses, and new lending libraries, where they could cast “light” on questions that had lurked in darkness for centuries.

The Enlightenment had roots in the Scientific Revolution. In 1687, Isaac Newton’s Principia, a work spanning three books, introduced “rational mechanics” into the study of mathematics and astronomy. Following Newton, Enlightenment thinkers believed that a “natural law” could be discovered for all aspects of the world. However, they did not think that people could discover this law through religious texts and leaders. Rather, it would be found by examining the world around them.

Some historians trace the Enlightenment’s political dimensions to the “Glorious Revolution” of 1688. King James of England, Ireland, and Scotland was deposed and replaced by his daughter Mary and her husband William of Orange. William ruled the Dutch Republic, a flourishing economic and intellectual center. A constitutional monarchy with a Parliament was established in Great Britain following the Glorious Revolution.

People in the Dutch Republic and in the new British constitutional monarchy had new forms of government. Although they still had monarchs, they also had representative parliaments and established “rights.” In 1690, the English philosopher John Locke argued that government should be formed through a contract between people and their ruler.

For many Enlightenment thinkers and artists, slavery became not only an ethical issue, but also a metaphor for different sorts of oppression and liberation. Radical artist William Blake used the theme frequently in his work.

The Enlightenment had economic, ethical, and religious aspects. In the 1690s, Locke was a shareholder in the Royal African Company, which profited from the enslavement of Africans. He argued that slavery was acceptable if it resulted from a justified war. He believed firmly in the right to private property, and enslaved people were considered property. Yet Locke rejected the idea that there were any fundamental differences between humans of different regions and races. During the eighteenth century, most Enlightenment thinkers took Locke’s lead and emphasized shared humanity between all people.

Yet African enslavement kept growing. Profits from the slave trade contributed to the growth of European cities. Enlightenment thinkers increasingly struggled with the fact that the apparent “progress” of the world around them depended on the horrible violence of slavery. Locke’s hypocritical position of criticizing slavery even as he benefited from it became harder to maintain. Religious groups like the Quakers, and philosophes like Jean-Jacques Rousseau and Adam Smith, called for the abolition of slavery.

The Enlightenment and historical “progress”

Who could participate in the Enlightenment, and who could benefit from it? Although more people became involved in these conversations, not everyone had an equal voice. Many philosophes believed that women, children, working people, and non-European people were less developed than white European men. Educational and social institutions needed to “prepare” these people to become more “reasonable” citizens of modern states.

The idea of women having political rights was almost nonexistent. One of the Enlightenment’s most revolutionary thinkers, Jean-Jacques Rousseau, believed that the goal of women’s education should be to please men. The English intellectual Mary Wollstonecraft wrote A Vindication of the Rights of Woman in 1792. Although it was a groundbreaking call for universal education, it was based on the idea that educated women would make better mothers. Even during the French Revolution, revolutionaries declared the “rights of man” rather than universal rights.

Ideas about development and racial difference were quite popular at the time. Scottish Enlightenment philosophers William Robertson and Adam Smith believed that societies moved through specific stages of development. This was part of the “natural law” they believed they were discovering. They believed that the final stage of human development was a society based in commerce and trade, much like Western Europe.

In The Wealth of Nations (1776), Smith presented his vision for a global economy. Smith’s economy depended on free trade. He believed that if “prejudices” were abolished and humans were given the freedom to make economic decisions, a society that benefited everyone would naturally arise.

Smith agreed that humans had not yet reached this ideal. He believed modern states should provide public services and education when the market could not. Yet Smith’s ideas about free markets became the intellectual foundation for the expansion of modern capitalism. Many of these ideas were also used to justify colonial occupations and conquest.

So was the Enlightenment really that revolutionary?

Historians disagree about whether the Enlightenment was truly revolutionary. It provided new tools for examining the world, and expanded a sense of shared humanity, but social and economic inequality remained. European Enlightenment philosophes were typically white, male, and well-off. They had a reason to want to improve existing institutions without completely revolutionizing them. Other people had less to lose. Calls for radical and even revolutionary change grew louder as more people saw the widening gap between the Enlightenment’s stated ideals and the actual state of the world.

Who were these rebels pushing the Enlightenment to become more radical? Historians say they were multi-racial, multi-national, and working class. Meeting on ships and in port cities across the Atlantic, these rebels demanded more radical change. One example was Olaudah Equiano, who had been both an enslaved laborer and a sailor and became a leading voice in the abolitionist movement.

Another abolitionist, French playwright Olympe de Gouges, wrote a work about women’s rights in 1791. She criticized women’s exclusion from the government formed during the French Revolution.

In Latin America, Enlightenment thinkers like José Antonio de Alzate y Ramirez criticized popular European ideas about native people. Alzate y Ramirez rejected the “natural laws” discussed by faraway philosophers. He said that local scholars had a better grasp of Amerindian society. His work later inspired Latin American independence movements in the nineteenth century.

However, influential elites continued to hold power. In some ways, modern states actually acquired more power over people’s everyday lives through mapping, taxation, and other practices. “Citizenship” was a powerful rallying cry for political participation, but it also left people out.

The Enlightenment left a complicated legacy. Although it was liberating, it also imposed limits on change. Perhaps it is best to think of the Enlightenment as a process, rather than a single thing. Even today, when you examine microscopic cells, write a novel, or carry a protest sign in the street, you are engaging in a process of “enlightened” thought.