All Thinkers

John Locke

John Locke was an English philosopher. He is one of the most influential political thinkers in world history. He was born on 29 August 1632 in a small village in Somerset, in the south-west of England. His father was a country lawyer who had fought on the side of Parliament in the English Civil War. Young John grew up during that war, watching England struggle over who should rule. He was a brilliant student. He went to Westminster School in London and then to Christ Church, Oxford. He stayed at Oxford as a teacher for many years. He studied medicine and science as well as philosophy. He worked with the famous scientist Robert Boyle. He was one of the first members of the Royal Society, Britain's most important scientific group. His medical training later saved the life of his friend and patron, Lord Ashley, by performing an operation to remove a cyst from his liver. Lord Ashley (later the Earl of Shaftesbury) became a powerful politician. Locke worked as his secretary, adviser, and family doctor. This brought Locke deep into English politics. When Shaftesbury fell out with King Charles II in the early 1680s, Locke too was in danger. He fled to the Netherlands in 1683. He stayed there for six years, writing the books that would make him famous. In 1688, King James II was overthrown in what English people called the Glorious Revolution. William and Mary took the throne. Locke returned home safely. In 1689 and 1690, he published three of the most important books of his age: A Letter Concerning Toleration, Two Treatises of Government, and An Essay Concerning Human Understanding. Each changed its field. He never married. He spent his last years at a country house in Essex, writing and corresponding with scholars across Europe. He died on 28 October 1704, aged 72.

Origin
England
Lifespan
1632-1704
Era
17th Century
Subjects
Philosophy Political Philosophy Empiricism Liberalism Enlightenment
Skills
Critical Thinking Ethical Thinking Research Skills Scientific Thinking Cultural Heritage And Identity
Why They Matter

Locke matters for three reasons. First, he laid the foundations of what we now call liberal political thought. He argued that all humans have natural rights to life, liberty, and property. Governments exist to protect these rights. A government that fails in this task can be resisted and replaced. These ideas shaped the American Declaration of Independence in 1776 and the French Declaration of the Rights of Man in 1789. Through these, they shaped the modern world. When people today talk about human rights, consent of the governed, and limits on state power, they are often echoing Locke, whether they know it or not.

Second, he wrote a new theory of knowledge. In his Essay Concerning Human Understanding (1689), he argued that we are not born with ready-made ideas in our heads. The mind at birth is, he said, like a blank page. Experience writes on it. Everything we know comes from our senses or from reflecting on what our senses have given us. This was a radical claim. Most philosophers before him had believed in inborn knowledge. Locke's view, called empiricism, shaped the development of modern science and psychology.

Third, he is a case study in the gap between a thinker's stated principles and his actions. Locke wrote beautifully about human liberty. He also invested in a company that traded enslaved Africans. He helped write a colonial constitution that protected slavery. His political theory treated property as a natural right in ways that later helped justify taking land from Indigenous people. He is not a simple hero of freedom. Reading him honestly means holding both his great ideas and his real failures together.

Key Ideas
1
Natural Rights to Life, Liberty, and Property
2
Government by Consent
3
The Mind as a Blank Page
Key Quotations
"All mankind... being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions."
— Two Treatises of Government, Second Treatise, Chapter II, 1689
This is Locke's basic ethical claim, stated at the start of his political theory. All humans are equal. No one has natural authority over another. No one may harm another's life, health, freedom, or things. This sentence is one of the foundations of modern rights talk. Locke is saying, in simple form, what many declarations of human rights have since said in fancier words. For students, it is a good starting point. The claim is bold. Are all humans really equal? In what sense? Locke thought they were equal in their basic rights, though not in everything. The idea has grown bigger over the centuries and now applies, in theory at least, to groups Locke himself might not have fully included.
"The end of law is not to abolish or restrain, but to preserve and enlarge freedom."
— Two Treatises of Government, Second Treatise, Chapter VI, 1689
Locke is challenging a common way of thinking about law. Many people then (and now) see law as a limit on freedom. More laws mean less freedom, they assume. Locke says the opposite. Good laws actually protect and grow freedom. Without laws against theft, your property is not safe. Without laws against violence, your life is not safe. Without these protections, you have no real freedom. Laws against these harms create the space in which freedom can flourish. For students, the idea is worth testing. It suggests that the question about a law is not 'does it limit me?' but 'does it protect the freedoms that matter most?' The answer can differ case by case.
Using This Thinker in the Classroom
Ethical Thinking When introducing students to human rights
How to introduce
Most students today have heard the phrase 'human rights'. Trace it back to Locke. He argued that every person has basic rights just by being human. Ask students: what rights do they think they should have? Usually they list things like freedom to speak, to be safe, to learn. Locke made this kind of thinking possible. His three core rights were life, liberty, and property. Modern rights lists are longer, but the basic Lockean idea (rights belong to persons, not to governments to hand out) is at the heart of them.
Research Skills When teaching students that knowledge comes from experience
How to introduce
Share Locke's image of the mind as blank paper written on by experience. Ask students: how do they actually learn things? By reading, yes. But mostly by trying, failing, asking questions, and paying attention. Locke's empiricism gives a framework for learning. Experience is the teacher. Books and teachers help you organise it, but the base material comes from actually doing, seeing, and thinking about what happened. This is a useful foundation for any kind of serious study.
Further Reading

For a first introduction, the Second Treatise of Government (Chapter V on property and Chapter VIII on government are key) is clearer and shorter than most people expect. Locke's A Letter Concerning Toleration is also short and readable. For a modern overview, John Dunn's Locke: A Very Short Introduction is reliable and clear. The BBC's In Our Time has good episodes on both Locke's politics and his philosophy of mind.

Key Ideas
1
The Right to Revolution
2
Toleration
3
The Theory of Property
Key Quotations
"Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas."
— An Essay Concerning Human Understanding, Book II, Chapter I, 1689
This is where Locke sets out his famous view of the mind. At birth, he says, the mind is like blank paper. Nothing is written on it yet. All knowledge will come from experience. The senses give us information. We then reflect on that information. From these two sources, our whole understanding is built up. The Latin phrase often used for this is 'tabula rasa', meaning 'clean slate'. For intermediate students, the quote is a good entry point into empiricism. It raises real questions. Do we really start with nothing? Modern psychology suggests babies have some built-in capacities (language learning, face recognition, basic physics of objects). Locke may have overstated his case. But his general direction, that experience matters deeply for what we end up believing, is widely accepted.
"Every man has a property in his own person. This nobody has any right to but himself. The labour of his body and the work of his hands, we may say, are properly his."
— Two Treatises of Government, Second Treatise, Chapter V, 1689
This is the foundation of Locke's theory of property. You own yourself. Therefore, you own your labour. When you mix your labour with something, it becomes yours. This simple chain of argument supports the right to private property. It also has a powerful implication: no one else has a right to own your labour. This was an early philosophical argument against slavery, even though Locke himself was personally involved in slavery. For intermediate students, the quote is worth thinking about carefully. The logic is clean. It says, in a few sentences, something radical: every human is the owner of themselves. Later abolitionists used exactly this argument against the slave system that Locke himself helped maintain.
Using This Thinker in the Classroom
Critical Thinking When teaching students to trace ideas through history
How to introduce
Read the opening of the American Declaration of Independence (1776). Compare it to passages from Locke's Two Treatises (1689). The similarities are striking. Jefferson and the other drafters borrowed Locke's framework almost directly. Ask students: what does it mean that a philosopher's ideas, written in exile in the Netherlands almost a century earlier, shaped the founding document of the United States? This is a concrete example of how ideas travel and take effect long after their authors are dead.
Ethical Thinking When discussing the difference between tolerating and accepting
How to introduce
Share Locke's argument for religious toleration. The state should not force people to believe a particular religion. Each person should follow their conscience. Then share the limits Locke put on his own idea: no toleration for Catholics or atheists. Ask students: how should a principle of toleration work? Locke's argument pointed further than he was willing to go. Later thinkers extended toleration to the groups Locke excluded. Most democratic countries today have fuller toleration than Locke proposed. This is a good case of how a principle can outgrow the person who first stated it.
Critical Thinking When discussing how philosophical ideas have real effects
How to introduce
Locke said that empty land could be claimed by whoever improved it through labour. Ask students: what happens when European colonists applied this argument to land that already had people living on it? Indigenous peoples in North America, Australia, and elsewhere had their own ways of using land, but not European-style farming. Colonists used something like Locke's argument to justify taking the land. Discuss: a philosophical idea can be a tool. Its effects depend partly on who uses it and how. Locke's property theory did real good (arguing for labour's value) and real harm (justifying land theft).
Further Reading

For deeper reading, all of the Second Treatise (about 120 pages) is worth the time. The Essay Concerning Human Understanding is longer but can be read in selections. John Marshall's John Locke, Toleration and Early Enlightenment Culture is a strong study of his political thought in context. Peter Laslett's edition of the Two Treatises has a classic introduction that shaped modern Locke scholarship.

Key Ideas
1
Locke and Slavery
2
The American Founders
3
Reading Locke Today
Key Quotations
"The great and chief end of men's uniting into commonwealths, and putting themselves under government, is the preservation of their property."
— Two Treatises of Government, Second Treatise, Chapter IX, 1689
Locke here makes property the main reason for government. This has been quoted often by people who want government to protect property rights above all else. But Locke's use of 'property' here is broader than we sometimes assume. He often uses it to mean 'life, liberty, and estate' (possessions) together. All three are things we own, in his framework. Government's job is to protect them all. Still, later readers, especially in the 19th and 20th centuries, often narrowed the meaning to material property. This gave Locke's theory a conservative use that the original argument does not fully support. For advanced students, the quote is a useful case of how a single line can travel away from its original meaning once removed from its context. Reading carefully, in full context, gives a different feel from reading the quote alone.
"No man's knowledge here can go beyond his experience."
— An Essay Concerning Human Understanding, Book II, Chapter I, 1689
This short sentence captures Locke's empiricism. Whatever you know, you know because experience has taught you. You may reason, compare, and extend. But the original material has to come from experience somewhere. Pure abstract reasoning, cut off from experience, leads nowhere for Locke. For advanced students, the claim has consequences. It shapes how we should approach any field. In science, it says we must look at the world, not just think about it. In politics, it says we should test ideas against how real societies actually work. In ethics, it says moral thinking must stay connected to real human life. Locke himself did not always live up to this. His own political theory sometimes ran ahead of the evidence. But the principle is still useful. Any knowledge that cuts itself off from experience is in trouble.
Using This Thinker in the Classroom
Ethical Thinking When discussing how thinkers can fail to live their own principles
How to introduce
Locke wrote that no one has the right to harm another's life, liberty, or property. He also held shares in the Royal African Company, which enslaved tens of thousands of Africans. He helped write a colonial constitution that legalised slavery. Discuss with students: how do we read a great thinker whose personal actions contradicted his stated principles? Do we reject him? Accept the inconsistency? The mature answer is neither simple rejection nor simple excuse. We name what he got right, name what he got wrong, and keep thinking. This is a pattern we have seen before with Rousseau, Jefferson, and others.
Critical Thinking When teaching students that major thinkers can be read in very different ways
How to introduce
Show students how Locke is claimed by liberals, conservatives, libertarians, and critics of colonialism, all using evidence from his actual writings. Ask: how can one thinker support such different readings? The answer is that rich thinkers produce texts with several threads. Different readers pick up different threads. Locke is a good case. His emphasis on rights fits liberalism. His emphasis on property fits conservatism. His emphasis on limited government fits libertarianism. His silences and blindspots fit the critical readings. Reading him carefully yourself lets you weigh these threads and form your own view.
Common Misconceptions
Common misconception

Locke was opposed to slavery in all forms.

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What to teach instead

He was not. He wrote strongly against political slavery (one nation ruling another, or a king treating his subjects as slaves). But he was personally invested in chattel slavery of Africans. He held shares in the Royal African Company and helped draft the Fundamental Constitutions of Carolina, which protected slaveholders' rights. His theoretical writing condemned slavery; his financial and political actions supported it. Scholars still debate why. Whatever the explanation, the simple picture of Locke as an anti-slavery hero is wrong.

Common misconception

Locke's idea of the blank slate means babies have no built-in abilities at all.

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What to teach instead

Locke himself was more careful. He did not deny that infants have certain instincts and basic capacities. He denied that there are inborn ideas or inborn moral principles already present at birth. Modern psychology has found some built-in abilities in babies that Locke would not have known about (language learning, face recognition, basic physics of objects). So the strongest form of the blank slate idea is probably wrong. But the general direction of Locke's argument, that experience matters deeply for forming knowledge, is still widely accepted.

Common misconception

Locke's toleration covered everyone.

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What to teach instead

It did not. His Letter Concerning Toleration specifically excluded Roman Catholics (because he saw them as loyal to the Pope) and atheists (because he thought they could not be trusted to keep their word). His toleration was an argument for protecting different Protestant groups from each other, not a universal principle. Later thinkers extended toleration to the groups Locke left out. His actual position was narrower than his famous principle. Reading him accurately means seeing both the broad idea and the specific exclusions.

Common misconception

Locke invented the idea of the social contract.

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What to teach instead

He did not. Thomas Hobbes had worked out a detailed version of social contract theory before Locke, in his book Leviathan (1651). Others before Hobbes had used related ideas. What Locke did was develop a very different version of the contract from Hobbes. Where Hobbes's contract gave almost absolute power to a ruler, Locke's contract kept major rights with the people and allowed for resistance when the government broke its trust. Locke's version, not Hobbes's, shaped later democratic thought. But he was working within a tradition, not inventing from nothing.

Intellectual Connections
In Dialogue With
Thomas Hobbes
Hobbes and Locke are the two great English social contract thinkers of the 17th century. Both started from similar questions. Why do people form governments? What makes government legitimate? Their answers went in opposite directions. Hobbes said people form government to escape a violent state of nature, and they should give almost all power to a single ruler. Locke said people form government to protect their natural rights, and they keep the right to remove a government that fails. Reading them together is one of the classic exercises in political philosophy. Two great thinkers, similar tools, very different conclusions.
Develops
Jean-Jacques Rousseau
Rousseau, writing about 70 years after Locke, took up the social contract tradition and pushed it further. Where Locke emphasised individual rights and limited government, Rousseau emphasised the community and the 'general will'. Both thinkers agreed that legitimate government comes from consent. They disagreed about what the consent looks like and how much power it gives the community over the individual. Reading them together shows how the social contract tradition developed across the Enlightenment. Locke gave it shape. Rousseau gave it a different shape.
Develops
Adam Smith
Smith, the 18th-century Scottish thinker, built parts of his economic theory on Locke's foundation. Locke had argued that labour creates property. Smith turned this into a theory of value and markets. Locke had argued for limited government. Smith argued for limited economic intervention. The line from Locke's political philosophy to Smith's economics shaped modern liberal thought. Reading them together shows a coherent tradition developing over a century, from natural rights to free markets.
In Dialogue With
Frederick Douglass
Douglass, the 19th-century African American abolitionist, used Locke's own arguments against the slave system Locke had profited from. Every person owns themselves. No one has the right to own another's labour. These are Lockean ideas. Douglass turned them into weapons against American slavery. This is a striking case. The slave owners quoted Locke on property. The enslaved people, and their allies, quoted Locke on self-ownership. Both sides could find support in his words. Douglass's use is the more faithful to Locke's stated principles, even though Locke himself did not follow them fully.
In Dialogue With
Mencius
Locke and Mencius agreed on surprising things across the 2000-year gap between them. Both thought human beings have rights that rulers must respect. Both thought government's job is to serve the people. Both believed that a ruler who fails in this can lose legitimacy. They differed on the source of these rights. Mencius rooted them in Heaven and in the moral seeds in each person. Locke rooted them in natural rights and consent. But the basic pattern is similar. Reading them together shows two careful thinkers reaching related conclusions about government by different paths.
Complements
Jeremy Bentham
Bentham sharply attacked Locke's idea of natural rights as 'nonsense on stilts'. Rights, Bentham said, come from laws made by governments, not from nature. Where Locke rooted government in inborn rights, Bentham rooted it in the happiness that government could produce. The two thinkers represent the two main traditions of modern political thought: rights-based and consequence-based. They do not always give different answers to specific questions. But they start from different foundations. Reading them together shows the most important division in liberal thought since the 18th century.
Further Reading

For research-level engagement, the Clarendon Edition of the Works of John Locke is the scholarly standard. Mark Goldie's work on Locke's political writings is important. For the slavery question, Bernasconi and Mann's essay 'The Contradictions of Racism: Locke, Slavery, and the Two Treatises' is widely cited. Domenico Losurdo's Liberalism: A Counter-History offers a sharp critical reading of Locke's tradition. The Journal of the History of Ideas regularly publishes current Locke scholarship.