Why This Matters
The Enlightenment wasn't just a period of smart people writing books—it was a fundamental revolution in how Europeans thought about power, knowledge, and human nature. On the AP European History exam, you're being tested on your ability to trace how these philosophical ideas caused real political change, from constitutional governments to revolutionary upheavals. The College Board explicitly wants you to connect thinkers like Locke and Rousseau to developments like the French Revolution and the Declaration of the Rights of Man.
Understanding these philosophers means grasping the intellectual toolkit that shaped everything from natural rights theory to economic liberalism to feminist thought. Don't just memorize who said what—know which concept each thinker represents and how their ideas challenged or reinforced existing power structures. When an FRQ asks about the "causes of the French Revolution" or "challenges to absolutism," these are your go-to examples.
Political Theory and the Social Contract
The social contract was the Enlightenment's most explosive political idea: government derives its legitimacy not from God or tradition, but from the consent of the governed. Different philosophers reached radically different conclusions about what this meant for political organization.
John Locke
- Natural rights (life, liberty, property)—Locke argued these rights exist before government and cannot be legitimately taken away, directly challenging divine-right monarchy
- Government by consent means rulers who violate natural rights can be overthrown; this justified revolution and influenced both American and French revolutionary documents
- Tabula rasa (blank slate) theory held that humans are shaped by experience, implying that better education and institutions could improve society
Thomas Hobbes
- "State of nature" as war of all against all—Hobbes saw humans as fundamentally self-interested, requiring strong authority to prevent chaos
- Leviathan (1651) argued for an absolute sovereign, making Hobbes an outlier whose social contract theory supported rather than challenged centralized power
- Influenced later thinkers by establishing social contract as the framework for political legitimacy, even though his conclusions differed dramatically from Locke's
Jean-Jacques Rousseau
- "General will" concept proposed that legitimate government expresses the collective interest of all citizens, not just majority rule or individual rights
- The Social Contract (1762) advocated popular sovereignty and direct democracy, providing intellectual ammunition for the radical phase of the French Revolution
- Challenged pure rationalism by emphasizing emotion and moral sentiment, making Rousseau a bridge figure between Enlightenment and Romanticism
Compare: Locke vs. Hobbes—both used social contract theory, but Locke justified limiting government power while Hobbes justified absolute authority. If an FRQ asks about Enlightenment challenges to absolutism, Locke is your example; if it asks about continuities with absolutism, Hobbes works.
Separation of Powers and Institutional Design
While some philosophers theorized about the origins of government, others focused on how governments should be structured to protect liberty. The key insight: concentrating power in one body invites tyranny.
Baron de Montesquieu
- Separation of powers into executive, legislative, and judicial branches became the blueprint for constitutional government worldwide
- The Spirit of the Laws (1748) analyzed how geography, climate, and culture shape political systems—an early form of comparative politics
- Direct influence on the U.S. Constitution and French revolutionary constitutions makes Montesquieu essential for any question about Enlightenment political legacy
Cesare Beccaria
- On Crimes and Punishments (1764) argued against torture and capital punishment as irrational and ineffective
- Proportional punishment principle held that penalties should fit crimes and deter future offenses, not exact revenge
- Reformed criminal justice across Europe as "enlightened despots" adopted his ideas, showing how Enlightenment thought shaped policy
Compare: Montesquieu vs. Rousseau—Montesquieu favored representative government with checks and balances, while Rousseau preferred direct democracy expressing the general will. Both challenged absolutism but proposed very different alternatives.
Empiricism, Reason, and the Limits of Knowledge
Enlightenment political ideas rested on deeper questions about how we know what we know. These epistemological debates shaped everything from religious skepticism to scientific method.
David Hume
- Radical empiricism argued all knowledge derives from sensory experience, leaving no room for innate ideas or metaphysical certainty
- Skepticism about causation—we observe correlation, not causation itself, undermining confident claims about natural and moral laws
- Religious skepticism challenged miracles and rational proofs of God's existence, contributing to Enlightenment secularism
Immanuel Kant
- Synthetic a priori knowledge resolved the empiricist-rationalist debate by arguing some knowledge (like mathematics) is both experiential and universal
- Categorical imperative—act only according to principles you could will to be universal laws—provided a secular foundation for ethics
- "Critique of Pure Reason" (1781) defined the limits of human understanding, arguing we can never know "things in themselves," only how they appear to us
Compare: Hume vs. Kant—Hume's skepticism "woke Kant from his dogmatic slumber," prompting Kant to find a middle ground between pure empiricism and rationalism. Both questioned religious certainty but reached different conclusions about moral knowledge.
Religious Criticism and Secularism
Enlightenment thinkers didn't just propose new ideas—they actively attacked traditional authority, especially the Catholic Church. Their weapons: satire, reason, and the printing press.
Voltaire
- Religious tolerance and free speech advocacy made Voltaire the Enlightenment's most famous public intellectual and its sharpest critic of the Church
- "Candide" (1759) satirized religious hypocrisy and philosophical optimism, using dark humor to expose social absurdities
- Deism—belief in a rational creator who doesn't intervene in human affairs—represented Voltaire's alternative to organized religion
Denis Diderot
- Encyclopédie (1751-1772) compiled Enlightenment knowledge into 28 volumes, deliberately challenging Church authority over education and truth
- Secularism and scientific inquiry promoted throughout the Encyclopédie made it a vehicle for spreading rationalist ideas across Europe
- Censorship battles with French authorities turned the Encyclopédie into a symbol of intellectual freedom versus traditional power
Compare: Voltaire vs. Diderot—both attacked the Church and promoted reason, but Voltaire worked through witty individual writings while Diderot organized a collaborative intellectual project. The Encyclopédie represents Enlightenment as a movement, not just individual genius.
Economic Liberalism
Enlightenment rationalism extended to economics, challenging mercantilism (the idea that governments should tightly control trade to accumulate wealth). The new argument: free markets, guided by rational self-interest, produce prosperity more efficiently than state control.
Adam Smith
- "Invisible hand" metaphor described how individual self-interest, channeled through free markets, unintentionally benefits society as a whole
- The Wealth of Nations (1776) attacked mercantilism and tariffs, arguing that laissez-faire (let it be) economics maximizes national prosperity
- Division of labor analysis showed how specialization increases productivity—the famous pin factory example demonstrated rational economic organization
Compare: Adam Smith vs. Mercantilism—Smith's free-market ideas directly challenged the state-controlled economic policies of absolutist monarchies. This connects Enlightenment economics to broader challenges against centralized authority.
Enlightenment and Its Limits: Gender and Equality
The Enlightenment proclaimed universal reason and natural rights—but most philosophes excluded women from full participation. A few thinkers exposed this contradiction.
Mary Wollstonecraft
- A Vindication of the Rights of Woman (1792) argued that women appear inferior only because they're denied education, not due to natural incapacity
- Extended Enlightenment logic to gender: if reason defines humanity and rights, then denying women education denies their humanity
- Foundation for feminist thought—Wollstonecraft's arguments anticipated 19th and 20th-century women's movements
Marquis de Condorcet
- Advocated women's suffrage and education, making him unusual among male philosophes in applying equality principles consistently
- Progress through reason—believed human society would continuously improve as rational principles spread
- Died during the Terror, illustrating how Enlightenment ideals could be consumed by the revolutions they inspired
Compare: Wollstonecraft vs. Rousseau—Rousseau argued women should be educated only to please men, while Wollstonecraft directly attacked this view as contradicting Enlightenment principles. This tension reveals the limits of "universal" Enlightenment claims.
Quick Reference Table
|
| Social Contract Theory | Locke, Hobbes, Rousseau |
| Natural Rights | Locke, Wollstonecraft |
| Separation of Powers | Montesquieu |
| Religious Criticism/Tolerance | Voltaire, Diderot, Hume |
| Empiricism | Hume, Locke |
| Economic Liberalism | Adam Smith |
| Criminal Justice Reform | Beccaria |
| Women's Rights | Wollstonecraft, Condorcet |
| Challenges to Pure Rationalism | Rousseau, Kant |
Self-Check Questions
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Which two philosophers both used social contract theory but reached opposite conclusions about the proper scope of government authority? What explains their different conclusions?
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If an FRQ asks you to explain how Enlightenment ideas challenged traditional sources of authority, which three philosophers would give you the strongest examples, and what specific institutions did each challenge?
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Compare and contrast how Locke and Rousseau understood individual freedom. Why might revolutionaries in France have found Rousseau's ideas more radical than Locke's?
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Mary Wollstonecraft argued that Enlightenment principles were applied inconsistently. What was her main critique, and which male philosopher did she specifically target?
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How did Adam Smith's economic ideas connect to broader Enlightenment themes about reason and limits on government power? What earlier economic system was he arguing against?