Five Philosophers of the Enlightenment

Reading of Voltaire’s tragedy of the Orphan of China in the salon of Marie Thérèse Rodet Geoffrin, by Lemonnier. / Wikimedia Commons

This new outlook put great emphasis on reason as the key to human progress.


The Enlightenment refers to a period of new thinking among many educated Europeans that began during the late 1600s. This new outlook put great emphasis on reason as the key to human progress. In the 1700s, this way of thinking became widespread in Europe.

Enlightenment thinkers were inspired by the example of scientists, such as Galileo, Bacon, and Newton. Scientists used observation and logic to understand the physical world. Their methods were rapidly overturning old beliefs. Now, thinkers wanted to take a similar approach to problems of human life. These thinkers wanted to forget the teachings of the past because they felt a new age of reason was dawning. In this new age, governments and social institutions would be based on rational understanding, not on errors and superstitions of earlier times.

A Frenchman, Bernard de Fontenelle, expressed this optimistic faith in reason and progress. In 1702, he wrote that the new century “will become more enlightened day by day, so that all previous centuries will be lost in darkness by comparison.”

In France, philosophes (philosophers) championed these new ideas. These thinkers often gathered in informal meetings, called salons, in private homes. There they exchanged and debated ideas. Many salons were organized by women. Gatherings like these helped to shape and spread the ideas of the Enlightenment.

The Roots of the Enlightenment


Enlightenment thinkers wanted to examine human life in the light of reason. Rational understanding, they felt, would lead to great progress in government and society.

These thinkers believed they were making a major break with the past. Like everyone, however, they were influenced by what had come before them. In this section, we will first examine the roots of the Enlightenment. Then we will consider ways in which the new ideas of the Enlightenment clashed with old beliefs.

The Scientific Revolution

Francis Bacon was a pivotal figure in establishing the scientific method of investigation. Portrait by Frans Pourbus the Younger (1617). / Łazienki Palace, Wikimedia Commons

Enlightenment thinking grew out of the Scientific Revolution. In science, observation and reason were revealing natural laws that applied throughout the physical world. The thinkers of the Enlightenment wanted to apply this approach to human life and experience. They asked questions such as: Are there natural laws that tell us how to live? How well do our current institutions follow natural laws? Do natural laws give all people certain rights? What is the best form of government

Philosophers did not always agree about the answers to these questions. What they all shared was a way of thinking about them. Like scientists, they placed their trust in reason and observation as the best sources of understanding and progress.

The Renaissance and the Reformation

The Enlightenment also had roots in the Renaissance and the Reformation. The humanists of the Renaissance questioned accepted beliefs. They celebrated the dignity and worth of the individual. During the Reformation, Protestants rebelled against the Catholic Church. They put individual conscience ahead of religious tradition and authority. Enlightenment thinkers went even further in rejecting authority and upholding the freedom of individuals to think for themselves.

Classical and Christian Influences

Like the humanists of the Renaissance, many Enlightenment thinkers were inspired by classical culture. Trust in reason, for example, goes all the way back to the ancient Greeks. So does the idea that people should have a voice in their government. Philosophers who argued for this idea could point to the democracy of ancient Athens or to the republic of ancient Rome.

Christian ideas also influenced Enlightenment thinking. Enlightenment philosophers preferred rational thought to faith based on the Bible. Yet most of them continued to believe in God. They saw the laws of nature as the work of an intelligent Creator. They saw human progress as a sign of God’s goodness. Often, their approach to moral problems reflected Christian values, such as respect for others and for a moral law.

New Ideas Versus Old Beliefs

The thinkers of the Enlightenment prized reason over authority. They questioned foundations of religion, morality, and government. Everything, they said, must be re-examined in the light of reason. This outlook led to many clashes with accepted beliefs and the ruling powers who upheld them.

Christian faith, for example, was based largely on trust in the Bible as God’s word. Enlightenment thinkers believed that humans were perfectly able to discover truth for themselves. Some of them even questioned the existence of God. Others sought a “natural religion” based on reason. To these thinkers, the order in the universe was proof enough of an intelligent Creator. They believed that there was no need to base belief in God on revelations in holy books. Similarly, they maintained that ideas about right and wrong should be based on rational insight, not on the teachings of religious authorities.

Enlightenment thinkers also criticized accepted ideas about government. Some questioned the long-held belief that God gave monarchs the right to rule. Many insisted that governments must respect individual rights. Toward the end of the 18th century, these ideas played a major role in revolutions in both America and France.

Cesare Beccaria: The Rights of the Accused

Cesare, Marquis Beccaria / Wikimedia Commons

Cesare Beccaria (beck-kah-REE-ah) was born in Milan, Italy, in 1738. He was a pioneer in the field of criminology. His work stressed the rights of accused people to fair treatment.

The son of an aristocrat, Beccaria attended a Catholic school as a boy. In 1758, he received a degree in law from the University of Pavia. When he finished his studies, he returned to Milan. There he was soon caught up in the intellectual excitement of the Enlightenment.

In 1763, Beccaria began a study of the justice system. He was upset by the harsh practices that were common in his day. Torture was often used to force confessions from accused persons or statements from witnesses to a crime. People might have their thumbs crushed in a device called a thumbscrew. Or they might have their bodies stretched on a device called a rack until their joints were pulled apart.

Beccaria objected to other practices, as well. It wasn’t unusual for trials to be held in secret. Judges were often corrupt. People found guilty of crimes were often sentenced to death.

Beccaria attacked these practices in a famous book called On Crimes and Punishments. He argued that laws exist to preserve security and order. Punishments, he said, should be designed to serve this purpose. Like other people, criminals made rational decisions. To stop people from committing crimes, punishment did not have to be brutal. It only had to be certain and severe enough to outweigh the potential benefits of the crime.

Beccaria also argued for other specific rights. A person accused of a crime, he said, should receive a fair and speedy trial. Torture should never be used. In addition, it was wrong to punish some people more harshly than others for the same crime. Punishment, he said, should fit the seriousness of the crime. He also believed that capital punishment—putting someone to death—should be ended completely.

Beccaria’s book encouraged the scientific study of crime. His ideas about rights and punishment influenced reform movements throughout Europe. In the United States, many laws concerning crime and punishment reflect his ideas.

John Locke: Natural Rights

Portrait of Locke in 1697 by Godfrey Kneller / Hermitage Museum, Wikimedia Commons

John Locke was born in England in 1632. His thinking about government and people’s rights had a major impact on the Enlightenment.

Thomas Hobbes had argued that kings should have absolute power. In contrast, Locke favored constitutional monarchy. In this type of government, a basic set of laws limits the ruler’s power.

Locke’s ideas reflected a long tradition of limitations on the English monarchy. This tradition dates to 1215, when English nobles forced King John to sign Magna Carta, or the “Great Charter.” Magna Carta established the idea that even monarchs had to obey English laws and respect certain individual rights.

Over time, Parliament became the main check on the monarch’s power. During the civil war of the 1640s, Locke’s father fought on the side of Parliament. The young Locke was greatly influenced by his father’s beliefs.

In the 1680s, another crisis developed. The new king, James II, was Catholic. His enemies in Protestant England feared that he wanted to put Catholics in power. In 1688, they forced James to flee the country.

In 1698, Parliament gave the crown to James’s Protestant daughter Mary and her husband, William. Parliament also passed a bill of rights. The English Bill of Rights strengthened the power of Parliament as the representative of the people. For example, it forbade the monarch to keep a standing army in peacetime or to levy taxes without Parliament’s consent. It also listed individual rights. Among them were protection in court cases from excessive fines and “cruel and unusual punishment.”

Locke approved of these changes in England. In 1690, he published Two Treatises of Government. In this book, he offered a theory of government that justified Parliament’s actions.

Locke denied the divine right of monarchs to rule. The true basis of government, he wrote, was a social contract, or agreement, among free people. Under this agreement, the purpose of government was to protect people’s natural rights. These included the right to life, liberty, and property. The people are the sole source of power. They agree to give power to the government to rule on their behalf. Therefore, according to Locke’s social contract, a government’s authority was based on the consent of the governed. If the government failed to respect people’s rights, it broke the contract and could be overthrown.

Locke’s view of government had a wide influence. In 1776, his ideas would be echoed in the American Declaration of Independence.

Montesquieu: Separation of Powers

Portrait of Montesquieu by an anonymous artist, 1728 / Palace of Versailles, Wikimedia Commons

Charles-Louis de Secondat was born in France in 1689. He is better known by his title, the Baron de Montesquieu (MON-tuh-skyoo).

In his youth, Montesquieu attended a Catholic school. Later he became a lawyer. When his uncle died in 1716, Montesquieu inherited the title of baron along with his uncle’s fortune. He also became president of the local parliament.

In 1721, Montesquieu achieved fame as a writer with a book called Persian Letters. The book described French society as seen by fictional travelers from Persia. It used humor to criticize French institutions, including the king’s court and the Catholic Church. It quickly became very popular, and Montesquieu became an admired guest in the salons of Paris.

Montesquieu’s most famous book was The Spirit of Laws, published in 1748. In this book, he described his theory of how governments should be organized.

Like John Locke, Montesquieu was concerned with how to protect political liberty. The best way to do this, he argued, was to divide power among three branches of government. In such a system, the legislative branch made the laws. The executive branch enforced the laws. The judicial branch interpreted the laws. In this way, no one branch would be too powerful. Montesquieu called this concept the separation of powers.

Montesquieu’s theory reflected his admiration for the English government. In England, Parliament made the laws. The monarch enforced the laws, and courts interpreted them. Each branch of government checked, or limited, the power of the others. When powers were not separated in this way, Montesquieu warned, liberty was soon lost. Too much power in the hands of any one person is called despotism.

Montesquieu’s ideas had a powerful impact on later thinkers. Among them were the men who wrote the U.S. Constitution. They made the separation of powers a key part of the American system of government.

Thomas Hobbes: Absolute Rule by Kings

Hobbes by John Michael Wright, 1670 / National Portrait Gallery, Wikimedia Commons

Thomas Hobbes was born in England in 1588. He wrote about many subjects, including politics and government. He tried to give a rational basis for absolute, or unlimited, rule by kings.

The son of a clergyman, Hobbes studied at Oxford University. As an adult, he traveled to other European countries, where he met many writers, scientists, and philosophers. He studied mathematics and science, as well as history and government. His studies inspired him to take a scientific approach to problems of human society.

Hobbes’s thinking about society was greatly influenced by events in England in the mid-1600s. King Charles I was struggling for power with Parliament, England’s lawmaking body. In 1642, civil war broke out between supporters of the monarch and Parliament. Hobbes sided with the king.

In 1649, the king was beheaded. For the next several years, England was ruled by Parliament’s House of Commons. But disorder and discontent continued. Finally, in 1660, the monarchy was restored.

The chaos of these years had a powerful impact on Hobbes. What, he asked, is the basis of social order? To answer this question, he tried to reason from his observations of human nature.

In Hobbes’s view, human beings were naturally cruel, selfish, and greedy. In 1651, he published a book called Leviathan. In this book, he wrote that people are driven by a restless desire for power. Without laws or other social controls, people would always be in conflict. In such a “state of nature,” life would be “nasty, brutish and short.”

Governments, Hobbes said, were created to protect people from their own selfishness. Because people were selfish by nature, they could not be trusted to make decisions that were good for society as a whole. Only a government that has a ruler with absolute authority could maintain an orderly society.

Later Enlightenment thinkers came to quite different conclusions about human nature and the best form of government. Hobbes was important, however, because he was one of the first thinkers to apply the tools of the Scientific Revolution to problems of politics. During the Enlightenment and the years that followed, many European countries moved away from absolute monarchy.

Voltaire: Religious Tolerance and Free Speech

Portrait of Voltaire by Nicolas de Largillière, c. 1724 / Palace of Versailles, Wikimedia Commons

Francois-Marie Arouet was born in France in 1694. Under the pen name Voltaire, he became one of the most celebrated writers of the Enlightenment.

As a young man, Voltaire attended a Catholic college in Paris. After college, he settled on a career in literature. He soon earned fame as a writer and as a witty participant in Paris salons.

Voltaire believed passionately in reforming society in the name of justice and human happiness. He warned against what he saw as superstition, error, and oppression. With biting humor, he attacked the French court and the power of the Catholic clergy.

Like Montesquieu, Voltaire admired England’s constitutional monarchy and separation of powers. In his view, the English were governed by law, not by the arbitrary wishes of a single ruler. To be governed by law, he said, was “man’s most cherished right. “

Voltaire was especially concerned with freedom of thought and expression. He championed religious tolerance. This means allowing people to practice religion in their own ways. Voltaire thought religious conflict was one of the main sources of evil in the world. He argued that no single religion possessed all the truth. At the same time, he held that there was a core of truth in all religions. This core was the “natural religion” that reason made available to everyone.

Voltaire also spoke out for the right of free speech. Once he wrote a letter to a man whose views he strongly opposed. He said that he would give his life so that his opponent could continue to write. A later writer expressed Voltaire’s feeling in the words, “I disapprove of what you say, but I will defend to the death your right to say it.”

Throughout his life, Voltaire criticized intolerance and oppression wherever he saw them. His outspokenness often led to conflicts with authorities. Twice, he spent time in prison. Several times, he was forced to flee to another city or country.

Voltaire’s ideas about religious tolerance and free speech greatly influenced colonial American political thinkers, such as Thomas Jefferson. They demanded that freedom of religion and free speech be included in the U.S. Bill of Rights.

Women of the Enlightenment


The women of the 1700s did not enjoy the same rights or status as men. Yet a number of women played an important role in the Enlightenment. Some helped spread Enlightenment thinking by hosting salons, and in their thinking and published writing. Others extended ideas about rights and equality to women.

Madame Geoffrin

Marie Thérèse Rodet Geoffrin / National Museum of Women in the Arts, Wikimedia Commons

One of the most prominent sponsors of salons was Madame Marie Thérèse Rodet Geoffrin (jhef-FRANH). Beginning in the mid-1700s, the brightest minds in Europe met in her home for lively talk about the latest ideas. Madame Geoffrin also gave financial support to the Encyclopedists, a group of men who put together the first encyclopedia.

At Madame Geoffrin’s salons, princes and politicians mingled with artists, writers, and philosophers. Geoffrin led these gatherings with a firm hand. She reserved Mondays for artists and Wednesdays for writers and philosophers.

Abigail Adams

Abigail Adams / Wikimedia Commons

Abigail Adams firmly supported America’s struggle for independence from England. She was married to John Adams, a leader of the American Revolution and the second U.S. president. During the war, she reminded John not to forget women’s rights in the new American government. She wrote, “If particular care and attention is not paid to the Ladies, we are determined to foment [start] a Rebellion.” Women, she went on, “will not hold ourselves bound by any Laws in which we have no voice.” Abigail also spoke out for a woman’s right to education.

Olympe de Gouges

Late-18th century portrait of Gouges by Alexander Kucharsky / Wikimedia Commons

French Olympe de Gouges was the daughter of a butcher. Despite having little education, she became an important writer and social reformer. In 1791, she published the Declaration of the Rights of Woman and of the Female Citizen. This document was her answer to the National Assembly’s Declaration of the Rights of Man and of the Citizen. De Gouges argued for women’s equality in every aspect of public and private life. Women, she said, should have the right to vote, hold office, own property, and serve in the military. They should have equal power with men in family life and in the church.

Mary Wollstonecraft

Mary Wollstonecraft by John Opie, c. 1797 / National Portrait Gallery, Wikimedia Commons

English writer Mary Wollstonecraft was another early leader in the struggle to gain equal rights for women. In an essay published in 1792, she argued that women deserve the same rights and opportunities as men. “Let woman share the rights,” she wrote, “and she will emulate [imitate] the virtues of men, for she must grow more perfect when emancipated [freed].”

Wollstonecraft believed that education was the key to gaining equality and freedom. She called for reforms to give women the same education as men. In the 19th century, her ideas about equality for women inspired early leaders of the women’s rights movement in the United States.

The Impact of the Enlightenment on Government

Enlightenment thinkers proposed new ideas about human nature and the best forms of government. Let’s take a look at the influence of these ideas in Europe and America.

Enlightened Rule

Frederick the Great portrait by Anton Graff, 1781 / Sanssouci, Wikimedia Commons

A few European absolute monarchs tried to apply Enlightenment ideas in the 1700s. Among them were Frederick the Great of Prussia, Catherine the Great of Russia, and Joseph II of Austria. These rulers became known as “enlightened despots” or “benevolent despots. ” Benevolent means “to be kind; to do good for others. “

Enlightened monarchs founded universities and scientific societies. They introduced reforms, such as greater religious tolerance and an end to torture and capital punishment. But these rulers pushed change only so far. They did not want to anger the noble classes, whose support they needed. Nor did they want to lose their own power.

The American and French Revolutions

The ideas of the Enlightenment greatly influenced leaders of the American Revolution. English colonists in America shared the traditions of Magna Carta and the English Bill of Rights, as John Locke had. When the colonists rebelled in 1775, they pointed to the abuse of their rights by the English king. The Declaration of Independence echoed Locke’s ideas on natural rights and the social contract.

The U.S. Constitution also contains ideas from the Enlightenment. The Constitution includes Montesquieu’s idea of separation of powers. The Bill of Rights protects the freedoms of religion and speech championed by Voltaire. It also supports some of the rights promoted by Beccaria, such as the right to a speedy trial.

In 1789, a revolution broke out in France, and the absolute monarchy there was overthrown. France’s National Assembly produced the Declaration of the Rights of Man and of the Citizen. This document proclaimed liberty and equality. It upheld the rights to own property and to resist oppression. It also guaranteed freedom of speech and religion. All these ideas grew out of the Enlightenment.

Originally published by Flores World History, free and open access, republished for educational, non-commercial purposes.



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