John Locke was an English Enlightenment philosopher who argued that government originates in the consent of the governed and exists to protect natural rights like life, liberty, and property, a social contract theory that rejected divine-right monarchy (AP Euro Topic 4.3, KC-2.3.III.A).
John Locke was the English philosopher who basically wrote the operating manual for Enlightenment politics. His core claim was simple but explosive. People are born with natural rights, and government only exists because individuals agree to it (a social contract) in order to protect those rights. If a ruler violates that agreement, the people can legitimately resist. That directly attacked the two traditional justifications for monarchy, divine right and tradition, which is exactly how the CED frames him (KC-2.3.III.A).
Locke also matters on the knowledge side of the Enlightenment. His empiricism, the idea that the mind starts as a blank slate and knowledge comes from experience, applied the Scientific Revolution's methods to human beings themselves. So Locke shows up in two ways in AP Euro, as a political theorist (consent of the governed, natural rights) and as an epistemological one (experience over inherited authority). Both versions point in the same direction. Authority has to be justified by reason and evidence, not just inherited.
Locke lives in Topic 4.3 (The Enlightenment) in Unit 4: Scientific, Philosophical, and Political Developments. He directly supports learning objective AP Euro 4.3.A, which asks you to explain the causes and consequences of Enlightenment thought on European society from 1648 to 1815, and AP Euro 4.3.B on its influence on intellectual development. The CED names him twice. KC-2.3.I.B pairs him with Rousseau as the developers of new political models based on natural rights and the social contract, and KC-2.3.III.A spells out his theory that the state comes from consent of the governed rather than divine right. He is the bridge between the Scientific Revolution's faith in reason (Unit 4 broadly) and the age of revolutions that follows in Unit 5. When you explain why the French Revolution or liberal reform movements happened, Locke is usually the intellectual cause you cite.
Keep studying AP® Euro Unit 4
Enlightenment Ideas (Unit 4)
Locke is the political anchor of the broader Enlightenment program. Where Voltaire attacked the church and Diderot compiled knowledge, Locke supplied the actual theory of legitimate government that the philosophes built on (KC-2.3.I.A and KC-2.3.III.A).
Individualism (Unit 4)
Locke's whole system starts from the individual. Society is made of self-interested individuals who choose to form a government, which flips the old model where you were born into obligations to king and church. That individual-first logic is the seed of classical liberalism.
American Revolution (Unit 5)
The clearest payoff of Locke's theory comes in Unit 5. 'Consent of the governed' and natural rights gave colonists, and later French revolutionaries, ready-made language for overthrowing rulers. Locke is the cause; the Atlantic revolutions are the consequence the CED wants you to trace.
Adam Smith (Unit 4)
Smith did for economics what Locke did for politics. Both replaced top-down authority (mercantilism, divine-right monarchy) with systems built on individual self-interest (KC-2.3.III.B). Pairing them is an easy way to show the Enlightenment's reach across institutions.
Locke is high-frequency exam material. Multiple-choice questions ask how his conception of natural rights challenged 17th-century justifications for monarchical authority, and how his empiricism changed European understanding of knowledge between 1648 and 1815. On the free-response side, the 2017 DBQ asked whether the Glorious Revolution of 1688 can be considered part of the Enlightenment, which is essentially a question about whether events on the ground matched Lockean theory. The 2021 DBQ on British rule in India asked whether imperial policy was primarily influenced by liberalism, the ideology descended from Locke. In both cases the move is the same. Don't just name Locke. Use his specific ideas (consent of the governed, natural rights, social contract) as evidence to evaluate whether a government or movement actually lived up to Enlightenment principles.
The CED groups them together (KC-2.3.I.B) because both built political models on natural rights and the social contract, so it's easy to blur them. Keep them apart this way. Locke's contract protects individual rights, especially property, and limits government. Rousseau's contract binds individuals to the 'general will' of the community, a more collective vision. Also note the CED's caveat that Rousseau argued for excluding women from political life (KC-2.3.I.C), a critique question that targets Rousseau, not Locke.
Locke argued that government originates in a social contract based on the consent of the governed, not in divine right or tradition (KC-2.3.III.A).
His theory of natural rights, including life, liberty, and property, meant rulers who violated those rights could legitimately be resisted.
Locke's empiricism applied the Scientific Revolution's methods to human knowledge, treating the mind as shaped by experience rather than inherited authority.
The CED pairs Locke with Rousseau as the two thinkers who developed new political models from natural rights and the social contract (KC-2.3.I.B), but Locke emphasized individual rights while Rousseau emphasized the general will.
On DBQs, Locke works as criteria, so you measure events like the Glorious Revolution or liberal imperial policy against his ideas of consent and rights, rather than just name-dropping him.
Locke believed people are born with natural rights (life, liberty, property) and that government exists only by the consent of the governed to protect those rights. If a government violates the contract, the people can resist it. He also argued knowledge comes from experience, not innate ideas.
Both built social contract theories, but Locke's contract protects individual rights and limits government, while Rousseau's binds individuals to the collective 'general will.' The CED also flags that Rousseau made controversial arguments for excluding women from political life (KC-2.3.I.C), a critique aimed at him rather than Locke.
Not exactly, and that nuance is exam gold. Locke's Two Treatises was published in 1689, right after the Revolution, and is often read as a justification of it after the fact. The 2017 AP Euro DBQ asked whether the Glorious Revolution can be considered part of the Enlightenment, so you need to argue both sides of that fit.
Yes. He's named in the CED twice in Topic 4.3 (KC-2.3.I.B and KC-2.3.III.A), shows up in multiple-choice questions on natural rights and empiricism, and his ideas underpin DBQs on the Glorious Revolution (2017) and liberalism in British India (2021).
Life, liberty, and property. The key AP point is that these rights exist before government, so government's only legitimate job is protecting them, which directly undermined divine-right monarchy.
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