Before the Enlightenment could happen, Europeans had to start doubting ideas that had been accepted for over a thousand years. That process is called the Scientific Revolution. It unfolded roughly between 1550 and 1700, and it changed everything.
What the Scientific Revolution overturned: For centuries, educated Europeans trusted two main authorities: the Bible and the ancient Greek philosopher Aristotle. Aristotle said the Earth was the centre of the universe and that heavy objects fall faster than light ones. The Bible was read to confirm a young Earth, roughly 6,000 years old. The Scientific Revolution proved both wrong — through observation, experiment, and mathematics.
Copernicus (1543)
Polish astronomer Nicolaus Copernicus published his claim that the Earth orbits the Sun — not the other way round. This heliocentric model directly challenged Church teaching and Aristotle. He delayed publication until his death to avoid persecution.
Galileo (1610s–1630s)
Italian scientist Galileo Galilei used a telescope to find moons orbiting Jupiter — proof that not everything in space circled the Earth. He also showed by experiment that all objects fall at the same speed regardless of weight. The Catholic Inquisition forced him to recant his views in 1633.
Kepler (1609–1619)
German mathematician Johannes Kepler worked out the precise mathematical laws describing how planets move in ellipses around the Sun. He gave the Copernican model the mathematics it had been missing.
Newton (1687)
English scientist Isaac Newton published his Principia Mathematica, explaining gravity as a universal force governing both falling apples and orbiting planets. His work appeared to show that the universe ran like a vast machine — regular, predictable, governed by laws humans could discover through reason.
Copernicus → Galileo → Kepler → Newton: each step moved authority from the Church to the human mind.
Why this matters for the Enlightenment: Newton's success gave thinkers a powerful idea: if reason and observation could unlock the laws of nature, could they also unlock the laws of human society? That leap — from physics to politics — is the core move of the Enlightenment. Writers began asking: what is the natural basis of government? Of religion? Of justice?
The Scientific Revolution also created a new method: observe, hypothesise, test, publish. The English philosopher Francis Bacon had already argued for this inductive method earlier in the century. His work spread the idea that progress was possible — that humans could improve their world through systematic inquiry.
Paper 3 framing: If a question asks about the origins of Enlightenment ideas, always begin with the Scientific Revolution. Examiners reward candidates who show that the Enlightenment did not appear from nowhere — it grew directly from the new confidence in human reason that Newton and others demonstrated. Link Copernicus → Galileo → Newton → the philosophes.
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The Enlightenment — also called the Age of Reason — was not one single set of ideas. It was a family of overlapping arguments, all sharing a belief that reason, evidence, and free enquiry could make human life better. The movement's writers are often called philosophes.
Four core Enlightenment goals: 1. Reason over tradition — no idea should be accepted simply because it was old or came from a king or priest.
2. Religious tolerance — persecution over differing beliefs was irrational and cruel.
3. Reform of government — rulers should govern for the benefit of citizens, not for their own glory.
4. Progress — human society could be improved through education, science, and better laws.
Key Enlightenment thinkers you must know
John Locke (1632–1704) — England
Locke argued that people are born with no innate ideas — the mind is a blank slate shaped by experience. In politics, his Two Treatises of Government (1689) claimed that rulers derive authority from the consent of the governed, and that citizens have natural rights to life, liberty, and property. If rulers violated those rights, the people had the right to resist. Locke's ideas directly inspired the American and French revolutions.
Voltaire (1694–1778) — France
François-Marie Arouet, who wrote as Voltaire, was the most famous philosophe in Europe. He attacked the Catholic Church, religious intolerance, and judicial cruelty with savage wit. His book Lettres philosophiques (1733) praised the English system of constitutional monarchy and religious tolerance as a model France should copy. He spent time at the court of Frederick II of Prussia and corresponded with Catherine II of Russia — both examples of his influence on rulers.
Montesquieu (1689–1755) — France
Charles-Louis de Secondat, Baron de Montesquieu wrote The Spirit of the Laws (1748), which argued that good government depended on separating power between different institutions — legislature, executive, and judiciary. He admired the English system of checks and balances. His idea of the separation of powers became foundational for modern constitutions, including the United States.
Jean-Jacques Rousseau (1712–1778) — Geneva/France
Rousseau stood apart from most philosophes. He argued that civilisation had corrupted naturally good human beings, and that true freedom came from living according to the general will. His Social Contract (1762) opened: 'Man is born free, and everywhere he is in chains.' Though harder to pin down than Locke or Montesquieu, Rousseau's ideas about popular sovereignty fed directly into the French Revolution.
Denis Diderot (1713–1784) — France
Diderot co-edited the Encyclopédie (1751–1772), a 28-volume attempt to collect all human knowledge organised by reason rather than religion. Contributors included Voltaire and Montesquieu. It was banned by royal decree twice but sold widely anyway. The Encyclopédie spread Enlightenment ideas to a wide middle-class audience and symbolised the movement's ambition: to use knowledge to reform the world.
Adam Smith (1723–1790) — Scotland
Scottish philosopher Adam Smith applied Enlightenment reasoning to economics. His Wealth of Nations (1776) argued that free markets — not mercantilist state control — best promoted prosperity. The 'invisible hand' of market competition would allocate resources efficiently if governments stopped interfering. Smith's work launched the discipline of modern economics and challenged the mercantilist assumptions behind absolutist economic policy.
Excluded from the exam: Louis XIV, Joseph II, Mozart: The IB guide explicitly states that Louis XIV, Joseph II, and the music of Mozart are NOT prescribed for this section. Do not spend essay time on them in Paper 3 questions about Absolutism and Enlightenment. They will not be named in questions, and if you name them in your answers without connecting them to prescribed content, you risk wasting words.
| Thinker | Country | Key work | Central idea |
|---|---|---|---|
| Locke | England | Two Treatises (1689) | Consent of governed; right of resistance |
| Voltaire | France | Lettres philosophiques (1733) | Religious tolerance; constitutional model |
| Montesquieu | France | Spirit of the Laws (1748) | Separation of powers; checks and balances |
| Rousseau | France/Geneva | Social Contract (1762) | General will; popular sovereignty |
| Diderot | France | Encyclopédie (1751–72) | Spread of rational knowledge |
| Adam Smith | Scotland | Wealth of Nations (1776) | Free markets; laissez-faire economics |
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The syllabus asks for a case study of Enlightenment ideas and their political impact in two countries. This section covers France and England/Scotland — the two most heavily examined choices and the two whose thinkers most directly shaped each other.
Case Study 1 — France
Why France was the centre of the Enlightenment: Paris became the intellectual capital of 18th-century Europe. The salons hosted by educated noblewomen like Marie Thérèse Rodet Geoffrin and Marie du Deffand gave philosophes a forum outside church or court censorship. Ideas moved fast. The Encyclopédie was printed in Paris (and secretly in Neuchâtel to dodge censors). By the 1770s, Enlightenment ideas were impossible to suppress — though the royal government kept trying.
- Political impact of Locke — French writers translated and built on Locke's argument that rulers governed by consent. This directly challenged the divine-right monarchy of the Bourbon kings.
- Voltaire's influence — Voltaire praised English parliamentary monarchy and religious freedom in Lettres philosophiques, implying that France's absolute monarchy and Catholic Church monopoly were inferior. The book was publicly burned by the Paris Parlement in 1734 — which only made it more popular.
- Montesquieu and the Parlement — French magistrates (members of regional parlements) used Montesquieu's argument for separation of powers to resist royal edicts throughout the 1750s–1780s. They positioned themselves as defenders of liberty against royal 'despotism'.
- The Encyclopédie — Royal censors banned it twice, but underground copies circulated. It normalised the idea that all institutions — Church, monarchy, the law — could be judged by the standard of reason and human welfare.
- Rousseau's Social Contract — By arguing that sovereignty lay with 'the people' rather than a king, Rousseau gave radical reformers a language of popular power that would explode in 1789.
Limit of change before 1789: Despite all this intellectual ferment, the French monarchy made few real reforms before 1789. The philosophes influenced elite opinion and eventually shaped revolutionaries — but absolutism survived until the financial and political crises of the 1780s brought the whole system down. Enlightenment ideas in France were radical in theory; their practical political impact came mostly after 1789, not before.
Case Study 2 — England and Scotland
England and Scotland are treated together in the IB guide because after the Act of Union (1707) they formed Great Britain. Intellectually they were already intertwined: Locke was English, and the Scottish Enlightenment produced some of the period's sharpest minds, including Adam Smith, David Hume, and Francis Hutcheson.
England as a model for continental Europe: Voltaire's visit to England in 1726–1729 convinced him that England had already achieved what France needed. England after the Glorious Revolution of 1688 had: a constitutional monarchy, a Parliament that controlled taxation, a Bill of Rights (1689) limiting royal power, and relative religious tolerance under the Toleration Act (1689). Continental philosophes pointed to England as proof that Enlightenment ideals could work in practice.
- Locke's practical impact in England — Locke wrote his Two Treatises to justify the Glorious Revolution after it happened. His language of natural rights and consent shaped how educated English people understood their own constitutional settlement.
- The Scottish Enlightenment — Edinburgh and Glasgow became leading intellectual centres. David Hume challenged religious certainty with philosophical scepticism. Adam Smith reframed economics. Francis Hutcheson developed the idea of moral sense — that humans have a natural capacity for ethical judgment independent of religion.
- Political stability as a precondition — Unlike France, Britain's constitutional settlement meant Enlightenment ideas could circulate without the same risk of censorship. Coffeehouses spread pamphlets and debate to a middling-class audience through the 18th century.
- Limits of change — Britain's Enlightenment was generally moderate: it reinforced existing institutions rather than demanding revolution. Parliament remained dominated by landowners; religious dissenters still faced civil disabilities; Scotland saw improvement but also the brutal suppression of Jacobite resistance after Culloden (1746).
France — Enlightenment under censorship
- Absolute monarchy; divine-right theory still official doctrine
- Catholic Church had legal monopoly; heresy laws enforced
- Philosophes relied on salons, underground printing, aristocratic patronage
- Ideas challenged the state — politically explosive
- Real impact came only with the Revolution of 1789
England/Scotland — Enlightenment within the constitution
- Constitutional monarchy after 1688; Parliament supreme
- Toleration Act (1689); relative religious freedom
- Coffeehouses, newspapers, universities spread ideas openly
- Ideas largely confirmed existing settlement — evolutionary
- Direct influence on law reform, economics, American colonies
How to use this case study in essays: If a question asks about the political impact of Enlightenment ideas in Europe, use France and England as a contrast pair: France shows that ideas could be radical but practically contained under absolutism — until the pressure became too great. England shows that Enlightenment ideas could be absorbed by a constitutional system and become a source of stability rather than revolution. That contrast is a strong analytical framework for a Band 5 essay.