In June 1633, an old man knelt on the cold stone floor of a convent in Rome. He was sixty-nine, nearly blind, and the most famous scientist in Europe. Before the assembled cardinals of the Roman Inquisition, Galileo Galilei read aloud a confession written for him: that he "abjured, cursed, and detested" his own claim that the Earth moves around the Sun. He had seen the truth through his telescope — the moons of Jupiter, the phases of Venus — yet here he was, renouncing it to save his life.
A legend says that as he rose, Galileo muttered under his breath, "Eppur si muove" — "And yet it moves." He almost certainly never said it. But the legend survives because it captures something real: by 1633, the heavens had already moved, and no Inquisition could nail them back in place. The question of this lesson is how a handful of mathematicians and observers overturned a cosmos that had stood for nearly two thousand years — and taught Europe to trust reason and evidence over ancient authority.
For roughly 1,800 years, educated Europeans inhabited a universe inherited from the ancient Greeks and baptized by the medieval Church. Its physics came from Aristotle (4th century BCE); its astronomy from Ptolemy (2nd century CE, Almagest). In this geocentric (Earth-centered) model, a motionless Earth sat at the center of creation, encircled by transparent crystalline spheres carrying the Moon, Sun, planets, and fixed stars in perfect circles. The heavens were made of an unchanging fifth element ("aether") and were perfect; the corruptible Earth was the realm of change and decay. This system was not merely science — it was woven into theology, with Heaven literally "up" beyond the stars and Hell at the center. To move the Earth was to move the throne of God.
Connections (backward): The Scientific Revolution did not appear from nowhere. Renaissance humanism (Lesson 1) revived ancient Greek texts — including rival astronomical and mathematical traditions like Pythagoras and Archimedes — and trained scholars to question received authority and read sources critically. The same humanist confidence that corrected the Latin Bible would soon correct Aristotle.
The first crack came from a cautious Polish cleric. Nicolaus Copernicus (1473–1543) proposed that the Sun, not the Earth, sat at the center — a heliocentric model. Placing the Sun at the center elegantly explained the puzzling backward ("retrograde") motion of the planets. Fearing controversy, Copernicus delayed publication for decades; his masterwork, On the Revolutions of the Heavenly Spheres (De revolutionibus orbium coelestium, 1543), reportedly reached him only as he lay dying. An unsigned preface (added by the theologian Andreas Osiander, not by Copernicus) softened the blow by presenting heliocentrism as a mere mathematical convenience rather than physical truth. Copernicus still kept perfect circles and even needed some of Ptolemy's correcting devices, so his system was not yet simpler or more accurate — but the Earth had begun to move.
The German mathematician Johannes Kepler (1571–1630), a devout Lutheran and sometime astrologer, took the next step. Working as assistant to the Danish observer Tycho Brahe and inheriting Brahe's unmatched naked-eye data on Mars, Kepler discovered that the planets do not move in perfect circles at all. His laws of planetary motion broke with two millennia of belief in heavenly perfection: - First law (1609): planets travel in ellipses, with the Sun at one focus. - Second law (1609): a planet sweeps out equal areas in equal times (it moves faster when nearer the Sun). Both appeared in Astronomia Nova (1609). - Third law (1619): a precise mathematical relationship links a planet's orbital period to its distance from the Sun (Harmonices Mundi, 1619).
Kepler made heliocentrism quantitatively accurate for the first time — but he could not say why the planets moved as they did. That answer waited for Newton.
While Kepler worked with numbers, the Italian Galileo Galilei (1564–1642) supplied evidence. In 1609 he built an improved telescope and turned it on the sky. What he saw shattered Aristotle's perfect heavens: mountains and craters on the Moon, spots on the Sun, four moons orbiting Jupiter (proof that not everything circles the Earth), and the phases of Venus (which only made sense if Venus orbited the Sun). He published these wonders in Sidereus Nuncius (The Starry Messenger, 1610).
Galileo also advanced a new physics of motion, arguing (against Aristotle) that objects fall at the same rate regardless of weight and that motion, once begun, persists — early steps toward the concept of inertia. He championed mathematics as the language of nature: the universe, he wrote, is "written in the language of mathematics."
His boldness brought him into collision with the Catholic Church. In 1616 the Church declared heliocentrism contrary to Scripture. When Galileo published his witty Dialogue Concerning the Two Chief World Systems (1632) — which made the defender of geocentrism, "Simplicio," look like a fool — the Roman Inquisition tried him in 1633, forced his recantation, and sentenced him to house arrest for the rest of his life. He died in 1642, the year Isaac Newton was born — Newton was born in 1642 by the Old Style (Julian) calendar England then used, which corresponds to 1643 by the modern New Style (Gregorian) calendar, so you will see his birth given as both years.
Connections (theme — intellectual change): Galileo's trial is the classic case study in the conflict between scientific inquiry and religious/political authority. But note the nuance: Galileo remained a believing Catholic, and many churchmen admired his science. The clash was less "religion vs. science" than a struggle over who has the authority to interpret nature and Scripture — the Church, or the individual investigator.
The revolution was not only about what people knew but how they claimed to know it. Two thinkers gave the age its rival methods.
The Englishman Francis Bacon (1561–1626), a royal official under James I, attacked reliance on ancient authority and championed empiricism: knowledge must be built from systematic observation and experiment. His inductive method reasoned from many particular observations to general conclusions. In Novum Organum (The New Organon, 1620) — its title a deliberate challenge to Aristotle's logical works, the Organon — he urged scholars to torture nature with experiments and let facts, not tradition, dictate truth. Bacon's vision of organized, useful, collaborative science would inspire the Royal Society.
The Frenchman René Descartes (1596–1650) took the opposite road. Distrusting the unreliable senses, he sought certainty through deductive reasoning — building, like a geometer, from self-evident first principles. In his Discourse on Method (Discours de la méthode, 1637) he resolved to doubt everything until he reached one thing he could not doubt: the fact that he was doubting, and therefore thinking. Hence his foundation: "I think, therefore I am" (French "Je pense, donc je suis"; later Latin "Cogito, ergo sum"). Descartes also proposed Cartesian dualism — the radical split between mind (thinking substance) and matter (extended substance) — which let scientists treat the physical world as a great machine governed by mathematical law.
Connections (compare): Bacon (induction, experiment, the senses) and Descartes (deduction, reason, doubt) represent the two poles of modern method — empiricism vs. rationalism. Real science needs both, and Newton would fuse them.
The capstone came from the Englishman Isaac Newton (1643–1727). In Mathematical Principles of Natural Philosophy (Philosophiæ Naturalis Principia Mathematica, 1687) — usually just the Principia — Newton united the heavens and the Earth under a single set of mathematical laws: - The three laws of motion (inertia; force equals mass times acceleration; action and reaction). - The law of universal gravitation: every body in the universe attracts every other with a force proportional to their masses and inversely proportional to the square of the distance between them.
With one principle, gravity, Newton explained Kepler's elliptical orbits, the fall of an apple, and the tides — proving that the same laws govern an apple and a planet. Aristotle's division between a perfect heaven and a corrupt Earth collapsed completely. The universe was now a vast, orderly, predictable machine, knowable through mathematics. Newton himself, modest about his debts, wrote that "if I have seen further it is by standing on the shoulders of giants."
Science became a collective, institutional enterprise backed by states eager for prestige and useful knowledge. England chartered the Royal Society (founded 1660), and France the Académie des Sciences (1666) under Louis XIV's minister Colbert — both offering patronage, publication, and a community of correspondents.
Women contributed but were systematically shut out of these institutions and universities. Margaret Cavendish, Duchess of Newcastle, published natural philosophy (Observations upon Experimental Philosophy, 1666) and in 1667 became the first woman to attend a meeting of the Royal Society — yet she was never admitted as a member. In Germany, the astronomer Maria Winkelmann discovered a comet in 1702 but was denied her late husband's post at the Berlin Academy of Sciences because she was a woman. Aristocratic patronage and family workshops were the main routes by which women could practice science at all.
Connections (forward): The Scientific Revolution handed the Enlightenment (Lesson 8) its founding faith: that the human mind, using reason and observation, can discover the laws governing everything — not just planets, but politics, economics, and society. If Newton could find the laws of the cosmos, thinkers like Locke, Voltaire, and Montesquieu reasoned, surely we can find the natural laws of good government.
Source: Galileo Galilei, Letter to the Grand Duchess Christina of Tuscany, 1615 (translation by Stillman Drake). [Authentic — widely anthologized; verify exact wording against Drake, Discoveries and Opinions of Galileo, 1957.]
"I think that in the first place it would be very prudent not to allow anyone to apply passages of Scripture in such a way as to force them to support, as true, conclusions concerning nature which... may be proved to the contrary by the senses or by necessary demonstrations.... The intention of the Holy Spirit is to teach us how one goes to heaven, not how the heavens go."
[Note: Galileo himself attributes the memorable final phrase to a learned churchman — generally identified as Cardinal Cesare Baronio. Galileo is quoting, not coining, it. Flag for reviewers.]
HAPPY analysis: - Historical context: Written in 1615, after Galileo's telescopic discoveries (1610) had made him famous and before the Church's 1616 condemnation of heliocentrism. Pressure on Galileo was mounting. - Audience: Christina of Lorraine, the influential Grand Duchess (mother of Galileo's patron, Cosimo II de' Medici), and through her, theologians and Galileo's critics. - Purpose: To defend heliocentrism from charges of heresy by arguing that Scripture and science occupy separate domains — the Bible teaches salvation, not astronomy — so neither can contradict the other. - Point of view: A devout Catholic and a working scientist who insists that "necessary demonstrations" about nature must guide how we read ambiguous Scripture, not the reverse. - whY it matters: The letter is a landmark argument for the independence of scientific inquiry from religious authority — yet it failed in the short term (it helped trigger the 1616 ban) and reveals that the famous "war" between science and religion was, for Galileo, a struggle within his own faith.
Why did the Scientific Revolution happen in early modern Europe? No single cause suffices; the AP exam rewards naming several. - Renaissance humanism revived ancient Greek mathematical and philosophical texts (Archimedes, Pythagoras, Plato) that offered alternatives to Aristotle, and trained scholars to challenge authority. - The printing press (Gutenberg, c. 1450) spread new findings across Europe rapidly, letting scattered investigators build on one another's work and compare data. - The Age of Exploration flooded Europe with new plants, animals, stars, and peoples that the ancients had never described — discrediting the assumption that the Greeks and Romans had known everything. - Patronage from princes, the Medici, and states (and later royal academies) funded instruments, observatories, and publication. - Navigational and commercial needs rewarded better astronomy, optics, and mathematics.
Results: intended — a mathematical, mechanical picture of nature and the institutionalization of organized science. Unintended — the long-term erosion of the Church's monopoly on explaining the natural world, and a model of "reason" that the Enlightenment would turn on society itself.
Compare — empiricism vs. rationalism: Bacon insisted truth is built upward from observation and experiment (induction); Descartes insisted it is deduced downward from indubitable first principles (deduction). The contrast maps onto national stereotypes (English experimentalism vs. French rationalism), but Newton's Principia fused both: mathematical deduction disciplined by experimental evidence.
Copernicus vs. Galileo vs. Newton — who did what? A favorite exam trap. - Copernicus (1543): proposed heliocentrism (Sun-centered) — but kept perfect circles. He started the revolution; he did not finish it. - Kepler (1609–1619): showed orbits are ellipses and made the math accurate. - Galileo (1610s–1630s): provided observational/telescopic evidence and was tried by the Inquisition (1633). He did not discover gravity. - Newton (1687): explained why with universal gravitation and the laws of motion — the synthesis.
Do not credit Newton's gravity to Galileo, or the telescope to Copernicus (Copernicus had no telescope — it was invented around 1608).
Scientific Revolution vs. Enlightenment: The Scientific Revolution (c. 1543–1687) was about understanding nature. The Enlightenment (18th century) applied that confidence in reason to human society — government, rights, economics, religion. Newton inspired the Enlightenment; he was not himself a philosophe.
Empiricism vs. rationalism: Empiricism (Bacon) = knowledge from the senses, observation, and experiment, reasoning inductively. Rationalism (Descartes) = knowledge from reason and deduction, distrusting the senses. Easy mnemonic: Bacon = Build up from facts; Descartes = Deduce down from doubt.
Galileo's trial myth: He was condemned for advocating heliocentrism as physical truth and disobeying the 1616 injunction, not for "inventing science." And he never publicly said "Eppur si muove."
Stimulus for Questions 11–12. Read the excerpt.
"I frame no hypotheses; for whatever is not deduced from the phenomena is to be called a hypothesis... and to us it is enough that gravity does really exist, and act according to the laws which we have explained, and abundantly serves to account for all the motions of the celestial bodies, and of our sea." — Isaac Newton, General Scholium, added to the Principia (1713) [authentic; Motte translation]
Stimulus for Questions 13–14. Read the excerpt.
"There are and can be only two ways of searching into and discovering truth. The one flies from the senses and particulars to the most general axioms... The other derives axioms from the senses and particulars, rising by a gradual and unbroken ascent, so that it arrives at the most general axioms last of all. This is the true way, but as yet untried." — Francis Bacon, Novum Organum (1620) [authentic; Spedding translation]
SAQ Rubric (3 points total, 1 per part) — see the Scoring Explanation in section (g). Award a point in each part only when the response is (a) specific and accurate, (b) draws a genuine contrast between medieval and new approaches, and (c) explains (not merely asserts) a downstream influence. No thesis or outside-the-prompt argument is required.
Read the secondary-source excerpt and answer parts (a), (b), and (c).
"What made the Scientific Revolution revolutionary was not any single discovery but a transformation in the very idea of knowledge. Where medieval scholars had sought truth by harmonizing observation with the authority of Aristotle and Scripture, the natural philosophers of the seventeenth century insisted that nature be interrogated directly, through observation, experiment, and mathematics. The result was not merely a new map of the heavens but a new confidence — soon to be inherited by the philosophes — that the human mind could uncover the hidden laws of the universe." — adapted from a modern historian's account of the Scientific Revolution [composite paraphrase written for this lesson; not a quotation from a specific scholar — clearly labeled]
(a) Briefly describe ONE specific development of the Scientific Revolution that supports the author's claim that natural philosophers "interrogated nature directly."
(b) Briefly explain ONE way the Scientific Revolution differed from the medieval approach to knowledge described in the excerpt.
(c) Briefly explain ONE way the "new confidence" of the Scientific Revolution influenced a later development in European history.
(a) Galileo Galilei used his telescope (1610) to observe the moons of Jupiter and the phases of Venus, gathering direct observational evidence that supported the heliocentric model rather than relying on ancient texts. (Alternative correct answers: Kepler's use of Tycho Brahe's observational data to show elliptical orbits; Bacon's call for systematic experiment in the Novum Organum; Newton's mathematical derivation of universal gravitation from observed phenomena.)
(b) Medieval scholars sought truth by reconciling observation with the established authority of Aristotle and Scripture, whereas Scientific-Revolution thinkers like Bacon and Galileo argued that direct observation, experiment, and "necessary demonstrations" should take priority over ancient authority — even when they contradicted Aristotle's physics or traditional readings of the Bible.
(c) The confidence that reason and observation could uncover universal natural laws carried directly into the Enlightenment: thinkers such as Locke, Montesquieu, and Voltaire applied a "Newtonian" search for natural laws to human society, arguing that reason could discover the natural laws of government, rights, and economics. (Alternative correct answers: it fed Deism, which pictured God as a "divine clockmaker"; it encouraged later state sponsorship of science and useful knowledge.)
MCQ Solutions
SAQ Rubric (3 points total, 1 per part) — see the Scoring Explanation in section (g). Award a point in each part only when the response is (a) specific and accurate, (b) draws a genuine contrast between medieval and new approaches, and (c) explains (not merely asserts) a downstream influence. No thesis or outside-the-prompt argument is required.
EuroIQ · Lesson 7 of 25 · Period 2 · Unit 4: Scientific Revolution & Enlightenment
This lesson is exam-prep study material aligned to the AP® European History Course and Exam Description. AP® is a trademark registered by the College Board, which is not affiliated with and does not endorse this product. Dates, attributions, and translations are drawn from standard scholarly sources; readers should consult primary editions for exact wording.
Content pending external history review.