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Discoveries made during the Scientific Revolution and on the voyages of discovery led to changes in Europe. A number of scholars were beginning to challenge long-held beliefs about science, religion, and government.

These new scholars relied on reason, or logical thought, instead of religious teachings to explain how the world worked. They believed human reason could be used to achieve three great goals—knowledge, freedom, and happiness—and that achieving these goals would improve society. The use of reason in guiding people’s thoughts about philosophy, society, and politics defined a time period called the Enlightenment. Because of its emphasis on the use of reason, the Enlightenment was also known as the Age of Reason.

The main ideas of the Enlightenment had their roots in other eras. Enlightenment thinkers looked back to the Greeks, Romans, and the history of Christianity. The Renaissance, Reformation, and Scientific Revolution provided ideas also.

Greek and Roman Philosophers

Enlightenment thinkers used ideas from the ancient Greeks and Romans. Greek philosophers had observed an order and regularity in the natural world. Aristotle, for example, taught that people could use logic to discover new truths. Building on Greek ideas, Roman thinkers developed the concept of natural law, the idea that a law governed how the world operated. With Greek and Roman beliefs as guidelines, Enlightenment thinkers began studying the world in a new way. They applied these beliefs not just to the natural world but also to the human world of society and government.


The history of Christianity in Europe provides other clues about ideas that emerged in the Enlightenment. One theologian, Thomas Aquinas, had taught in the Middle Ages that faith paired with reason could explain the world. Although it was indebted to Aquinas, the Enlightenment was mostly a secular, or non-religious, movement. Enlightenment thinkers disagreed with the church’s claims to authority and its intolerance toward non-Christian beliefs.

The Renaissance and Reformation

Other reactions to the Christian Church in Europe also influenced the ideas of the Enlightenment. For example, some Renaissance thinkers used Greek and Roman ideas to raise questions about established religious beliefs. These Renaissance thinkers were known as humanists. Although most humanists were religious, they focused on human value and achievement rather than the glory of God.

Renaissance humanists believed people could improve their world by studying it and changing it. These ideas contributed to the Enlightenment idea of progress— the idea that humans were capable of improving their world. Some Reformation ideas also reappeared during the Enlightenment. Like Martin Luther and other reformers, Enlightenment scholars questioned church authority. They found that religious beliefs didn’t always fit in with what they learned from their logical study of the world.

The Scientific Revolution

The Scientific Revolution also influenced Enlightenment thinkers. Through experiments, scientists like Newton and Galileo had discovered that the world did not work exactly the way the church explained it. Using scientific methods of study, scientists discovered laws that governed the natural world. Enlightenment thinkers took the idea of natural laws one step further. They believed that natural laws must also govern human society and government.



Enlightenment thinkers borrowed ideas from history to develop a new worldview. They believed the use of reason could improve society. To achieve this progress, they had to share their ideas with others.

French PhilosophersEnlightenment_-_Voltaire.jpg

French philosophers popularized many Enlightenment ideas. One philosopher, Voltaire (vohl-TAYR), mocked government and religion in his writings. Instead of trusting God to improve human happiness, Voltaire believed humans could improve their own existence. Having gotten in trouble for some of his writings, Voltaire also spoke out against censorship—removal of information considered harmful. He argued, “I [may] disapprove of what you say, but I will defend to the death your right to say it.” His statement emphasized the Enlightenment goal of freedom of thought.

Enlightenment thinkers made an effort to share their thoughts with the public. Philosopher Denis Diderot (dee-DROH) edited a book called the Encyclopedia. This book included articles by more than 100 experts on science, technology, and history. The French king and the pope both banned the Encyclopedia. In spite of censorship, Enlightenment ideas spread. One important place for the exchange of ideas was the salon, a social gathering held to discuss ideas. Women often hosted the salons. Most Enlightenment thinkers did not view women as equal to men. However, in hosting salons women could influence opinions.

British Writers

Women and men also began to publish their ideas in books, pamphlets, and newspaper articles. British writer Mary Wollstonecraft, for example, argued that women should have the same rights as men. Enlightenment thinkers even applied their ideas of freedom and progress to economics. British writer Adam Smith believed economics was governed by natural laws. He argued that governments should not try to control the economy and that economic growth came when individuals were free to make their own choices. Like many Enlightenment thinkers, his ideas would have a lasting effect.


In the 1600s and 1700s kings, queens, and emperors ruled Europe. (See the map on the next page.) Many of these monarchs believed that they ruled through divine right. That is, they thought that God had given them the right to rule as they chose. They also thought they shouldn’t be limited by bodies such as England’s parliament. King Louis XIV of France saw himself as the entire government. He declared, “L’état, c’est moi!” or “I am the state.”

Although monarchs such as Louis XIV held the most power, other groups in society also had privileges. In France, for example, the nobles paid few taxes and held the highest positions in the army. The French clergy paid no taxes at all. However, most of the French people, the commoners, were poor, paid high taxes, and had no role in their government.

Outside of France, some monarchs began to change their ideas about how they ruled. They applied Enlightenment ideas to government. These rulers became known as enlightened despots. A despot is a ruler with absolute power. The enlightened despots tried to make life better for the commoners. They also thought they could make their countries stronger if the commoners were happier. Frederick II of Prussia was one such ruler. He approved reforms in law and education. Empress Catherine the Great of Russia was another enlightened despot. Her reforms gave the Russian nobility greater rights and powers.

Although the enlightened despots made some improvements in their countries, many Enlightenment thinkers looked for bigger changes. They began to consider the need for democracy.



Some Enlightenment thinkers only challenged the idea of rule by divine right. Others went further. They developed some completely new ideas about how governments should work. Three of these thinkers— Locke, Montesquieu, and Rousseau—tried to identify the best possible form of government. The ideas of these Enlightenment thinkers contributed to the creation of modern democracy.


The English philosopher John Locke had a major influence on Enlightenment political thought. In 1690, he published Two Treatises on Government. In this work, Locke argued for government as a contract between the ruler and the people. Because a contract bound both sides, the ruler’s power would be limited. In fact, Locke thought that government existed only for the public good of the people. Locke also declared that all people had certain natural rights, which included the rights to life, liberty, and property. He thought that no person was born with special privileges. According to Locke, the government should protect the natural rights of its citizens. If it didn’t, the people had the right to change rulers.


Frenchman Charles-Louis Montesquieu (mohn-te-SKYOO) was a member of the nobility. He built on Locke’s ideas in The Spirit of the Laws, published in 1748. Montesquieu claimed that a government should be divided into separate branches to protect people’s freedom. In this idea, known as the separation of powers, each branch of government is limited by the others. As a result, the separate branches must share power. None of them can control the government completely.


French thinker Jean-Jacques Rousseau (roo-SOH) criticized divine right. He believed in popular sovereignty (SAHV-ruhn-tee)—the idea that governments should express people the will of the people. In The Social Contract, published in 1762, Rousseau declared, “Man is born free, but he is everywhere in chains.” According to Rousseau, citizens submit to the authority of government to protect their own interests, entering into a “social contract.” This contract gives the government the power to make and enforce laws as long as it serves the people. The government should give up that power if it is not serving the people.



Enlightenment ideas inspired commoners to oppose monarchies that ruled without concern for the people’s needs. However, the monarchs wouldn’t give up their privileges. In England, Parliament forced the monarchy to change.

Trouble with Parliament
For many years, the English Parliament and the English monarchy had an uneasy relationship. Parliament demanded that its rights and powers be respected. However, the monarchy stood for rule by divine right. The relationship between English monarchs and Parliament got worse. The conflict led to a civil war in 1642. Representatives of Parliament led by Oliver Cromwell took over the country. The king, Charles I, was charged with various crimes and beheaded in 1649. Cromwell became a dictator. The years of his rule were troubled and violent.

By 1660 many English people were tired of turmoil and wanted to restore the monarchy. They invited the dead king’s son to return and rule England as Charles II. They made Charles promise to allow Parliament to keep the powers it had won in the civil war. These powers included the right to approve new taxes. Parliament was able to work with Charles II during most of his rule. However, when Charles died and his brother James became king, the trouble began again. James II, an unpopular Catholic, tried to promote his religious beliefs in England, a Protestant country. As a result, Parliament invited the Protestant William of Orange, James’s son-in-law, to invade England. When William and his wife, Mary, arrived in England in 1688, James and his family fled to France.

Parliament offered the throne to William and Mary on one condition. They had to accept the English Bill of Rights, a document that listed rights for Parliament and the English people. This document, approved in 1689, drew on the principles of Magna Carta, which limited a ruler’s power and recognized some rights for the people.
Magna Carta had been in place for hundreds of years, but the monarchs had not honored it. William and Mary agreed to honor Magna Carta. They also agreed that Parliament could pass laws and raise taxes. As a result, the monarchs ruled according to laws passed by Parliament. Divine right to rule had ended in England.



The French king ruled over a society split into three groups called estates. The clergy were members of the First Estate and enjoyed many privileges. Nobles made up the Second Estate. They held important positions in the military, the government, and the courts.

Most French people belonged to the Third Estate. Included were peasants, craftworkers, and shopkeepers. The Third Estate paid the highest taxes but had few rights. Many members of the Third Estate were poor and hungry. They felt that the king didn’t understand their problems. While the common people starved, King Louis XVI had fancy parties. His queen, Marie-Antoinette, spent huge amounts of money on clothes. Meanwhile, the government was badly in debt. Louis XVI wanted to raise money by taxing the rich. To do so, in 1789 he called together members of the three estates.

The meeting did not go smoothly. Some members of the Third Estate were familiar with Enlightenment ideas. These members demanded a real voice in the meeting’s decisions. Eventually, the Third Estate members formed a separate group called the National Assembly. This group demanded that the king accept a constitution limiting his powers. Louis XVI refused to agree to such demands, angering the common people of Paris. Violence broke out on July 14, 1789. On that day a mob stormed a Paris prison, the Bastille. After forcing the guards to surrender, the mob took guns stored inside the building and freed the prisoners. The French Revolution had begun.

Revolution and Change

After the Bastille fell, the revolution spread to the countryside. Peasants there were afraid that the king and nobles would crush the revolution. In events called the Great Fear, peasants took revenge on their noble landlords for years of poor treatment. In their rage and fear, the peasants burned country houses and monasteries.
Other leaders of the revolution were taking peaceful steps. The National Assembly wrote a constitution. It included some of the same ideas found in the writings of Enlightenment philosophers, the English Bill of Rights, and the Declaration of Independence. Called the Declaration of the Rights of Man and of the Citizen, this document guaranteed some freedoms for citizens and distributed the payment of taxes more fairly. Among the rights the Declaration supported were freedom of speech, of the press, and of religion. It also guaranteed that men could take part in the government.

Louis XVI was forced to accept the new laws, but new laws did not satisfy the revolution’s leaders. In 1792 they ended the monarchy and created a republic. The next year, the leaders put Louis XVI on trial and executed him. Facing unrest, in 1793 the new French government began to order trials of anyone who questioned its rule. In the period that followed, called the Reign of Terror, thousands of people were executed with the guillotine. This machine beheaded victims quickly with a heavy blade. The Reign of Terror ended when one of its main leaders, Maximilien Robespierre, was himself executed in July of 1794.

Although the Reign of Terror was a grim chapter in the story of the French Revolution, the revolution wasn’t a failure. Eventually, France created a democratic government. Enlightenment ideas about freedom were powerful. Once they took hold, they would not go away. Many Europeans and Americans enjoy freedoms today thanks to Enlightenment ideas.