John Locke (1632–1704) was a major contributor to the Age of Enlightenment, which was being formed by philosophers in Europe during the late seventeenth and early eighteenth centuries. John Locke’s influence was profound in three important areas: government, religion, and education.

In order to understand Locke’s thinking about government, it is necessary to understand his views on human nature. He believed that humans in a state of nature were born with certain rights. They had the right to physical safety, the right to their own ideas and beliefs, and the right to their property. In order to defend these rights, humans banded together under a social contract into civil societies that could help defend them from encroachment. It was the job of government to protect these rights, although to do so meant that some individual rights had to be given up in order to secure the most basic rights. However, should government overstep their bounds and negate rights through tyranny, people had the right to turn to rebellion to restore their basic rights to physical safety, thoughts, and property. In order to maintain natural rights, there needed to be a division of power within a government in order to keep tyranny at bay.

Since each individual had the right to his own thoughts and ideas, governments did not have the right to dictate religious thought. Locke believed in religious toleration and that a state could not force its people into a state-sanctioned religion.

Locke believed that humans born into a state of nature were born with minds that were a blank slate. Anything that humans knew came from experience and not from anything inborn. This meant that education was very important, and it was important to guide children into forming a sense of right and wrong rather than dictating precepts. He also felt that what children experienced early in life profoundly influenced their views throughout life. He believed in rational thought based on empiricism, in which experience leads to theories which can be tested through further experience.

Locke’s views were elucidated in several important writings, including “Two Treatises Concerning Government,” “A Letter Concerning Toleration,” and “Some Thoughts Concerning Education.” His influence has been seen in England’s Glorious Revolution of 1688, the American Revolution, the French Revolution, and many other revolutions and movements. His influence is also seen in the writings of philosophers and theorists such as Rousseau, Voltaire, Bacon, Jefferson.

John Locke's most important impact on European society was in providing a radical alternative to established political theories. In Locke's day, the Divine Right of Kings was still widely held throughout Europe. This age-old political theory argued that monarchs owed their power to God and God alone. They had been appointed to rule by God himself, and it was therefore not just treason but outright blasphemy for their subjects to defy them in any way.

It was in opposition to one such variant of the Divine Right theory, that provided by Sir Robert Filmer, that Locke articulated his own social contract theory of government. Locke argued that a better, more accurate way of looking at political society was to see it as emerging from an agreement between its members and their sovereign ruler to preserve private property and generally maintain good order. On this basis, the monarch existed to fulfill a certain contractual obligation, namely to protect his subjects' lives and property. If he failed to fulfill his side of the bargain, then his subjects were perfectly entitled to replace him with another monarch or another system of government that would more effectively protect their inalienable rights.

Locke's thought proved hugely influential, not just in Europe, but in the American colonies. American colonists drew extensively upon Locke's social contract theory to justify rebelling against King George III and establishing a representative government of their own.

John Locke's major influence on European society, and democratic societies everywhere, was his authorship of his Two Treatises on Civil Government, published just after the British Glorious Revolution of 1688. In his first Treatise, he discusses the reasoning used to justify absolute monarchy and divine right as espoused by Hobbes. Ultimately he dispenses with this form of government as not justifiable with the laws of nature:

He, that shall consider the distinct rise and extent, and the different ends of these several powers, will plainly see, that paternal power comes as far short of that of the magistrate, as despotical exceeds it; and that absolute dominion, however placed, is so far from being one kind of civil society, that it is as inconsistent with it, as slavery is with property. Paternal power is only where minority makes the child incapable to manage his property; political, where men have property in their own disposal; and despotical, over such as have no property at all.

In his Second Treatise, Locke argues that all men are born with certain "natural rights," those rights being life, liberty and estate (property.) He argues that governments were created to protect those rights and people have the right to change their government if it no longer protects those rights.

The idea of rights which the people possess naturally was used by many European people to justify constitutional monarchies, those in which the monarch himself is not above the law. It was relied upon extensively by Thomas Jefferson in writing America's Declaration of Independence from Great Britain.