Scientific Revolution

Period: 1543 (De Revolutionibus by Copernicus) – 1687 (Principia by Newton) | Context: rupture with Aristotelian-Ptolemaic cosmology; birth of modern science as mathematical and experimental investigation of nature

Context

The Scientific Revolution transforms the worldview: from the Earth as center (Ptolemy + Aristotle) to a heliocentric and then infinite universe. Science ceases to be essentialist contemplation of substances (Aristotle) and becomes quantitative, mathematical, and experimental investigation of phenomena. Copernicus, Kepler, and Galileo are heirs of Neoplatonism (God geometrizes the world); Newton synthesizes everything into universal physics.

I. Nicolaus Copernicus (1473–1543)

Synopsis

Polish canon; died the same year he published his masterwork — received the first copy on his deathbed.

Theses

• Heliocentrism: the Sun, not the Earth, is at the center of the universe
• The Earth is spherical, revolves around the Sun and rotates on its own axis
• The movement of celestial bodies is circular and uniform (still an Aristotelian presupposition)
• The dimension of the universe is immensely greater than previously thought
• Metaphysical basis: realist interpretation of Platonism — the Sun as symbol of the highest Good

Impact

Initiated the “Copernican revolution” — not only in astronomy, but in philosophy (Kant will use the term for his own epistemological turn)

References

• On the Revolutions of the Celestial Spheres (De Revolutionibus Orbium Coelestium, 1543)
• Alexandre Koyré, From the Closed World to the Infinite Universe

II. Tycho Brahe (1546–1601)

Synopsis

Danish astronomer; systematic observer without a telescope; largest celestial database of the era.

Theses

• Proposed a third system: the Earth remains at the center; the Sun and Moon revolve around the Earth; the 5 planets (Mercury, Venus, Mars, Jupiter, Saturn) revolve around the Sun
• Rejected both Ptolemy and Copernicus

Legacy

His data were inherited by Kepler, who used them to demonstrate elliptical orbits.

III. Johannes Kepler (1571–1630)

Synopsis

German astronomer and mathematician; convinced Copernican and Neoplatonist. Believed that God is a geometer and nature obeys mathematical rules. Studied the motion of Mars for 10 years.

Kepler’s Three Laws

1. First Law (elliptical orbits): the orbits of planets are ellipses, with the Sun at one of the foci
2. Second Law (equal areas): the line connecting the Sun to the planet sweeps equal areas in equal times — the planet accelerates near the Sun
3. Third Law (harmony): the square of the period of revolution is proportional to the cube of the mean distance from the Sun (T² ∝ a³)

Metaphysics of the Sun

Pythagorean mysticism: the Sun as image of God the Father; the universe as image of the Trinity (Sun/space/motion)

References

• New Astronomy (Astronomia Nova, 1609) — 1st and 2nd laws
• Harmony of the World (Harmonices Mundi, 1619) — 3rd law
• Cosmic Mystery (Mysterium Cosmographicum, 1596)

IV. Galileo Galilei (1564–1642)

Synopsis

“Father of modern science”. Brings the telescope to astronomy; empirically confirms heliocentrism; founds modern mechanics.

Scientific Contributions

• Telescope (perfected in 1609): mountains on the Moon, 4 moons of Jupiter, phases of Venus, sunspots — contradictions to celestial Aristotelianism
• Mechanics: law of falling bodies; law of the pendulum; principle of inertia (anticipates Newton)
• Idealized experiment: the Pisa tower experience (leaning tower) probably never occurred physically — it was a thought experiment, as Alexandre Koyré demonstrated

Scientific Method

• Mathematical realism: “The book of nature is written in the language of mathematics” (Il Saggiatore)
• Not essentialist (abandons the search for Aristotelian substances)
• Quantitative research: mechanical causes, not final causes
• Combines Platonism in philosophy (the real is mathematical) with Aristotelianism in method (starting from phenomena)

The Trial (1633)

• In 1616, the Church condemns heliocentrism as heretical
• Dialogue Concerning the Two Chief World Systems (1632) — condemned at trial
• Sentenced to house arrest until death (1642); the sentence was revoked by the Church in 1992

Science and Faith

“Both-and” position, not “either-or”: science and faith occupy distinct domains; the Bible teaches how to go to heaven, not how heaven functions

References

• Sidereal Messenger (Sidereus Nuncius, 1610)
• Il Saggiatore (1623) — mathematical language of nature
• Dialogue Concerning the Two Chief World Systems (1632)
• Discourses and Mathematical Demonstrations Relating to Two New Sciences (1638) — mechanics
• Alexandre Koyré, Galilean Studies

V. Isaac Newton (1643–1727)

Synopsis

Greatest synthesis of the Scientific Revolution. Unifies celestial and terrestrial mechanics in a single law; founds classical physics that will dominate until Einstein. Foundation of Empiricism (Hume, Locke), of the Enlightenment and Kant’s critical philosophy (“the starry heavens above me”).

The Law of Gravity

• All bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance (F = G·m₁·m₂/r²)
• A single principle explains the fall of apples and the motion of planets

The Three Laws of Motion

1. Inertia: a body at rest remains at rest and one in uniform rectilinear motion continues thus, unless an external force acts
2. Force = mass × acceleration (F = m·a)
3. Action and reaction: for every action there is an equal and opposite reaction

Four Rules of Philosophy (Principia, Book III)

1. Admit no more causes than are necessary and sufficient
2. Assign the same causes to natural effects of the same kind
3. Universal qualities confirmed by experiments must be assumed as properties of all bodies
4. Propositions inferred from phenomena by general induction must be taken as true until exceptions arise

Philosophy and God

Newton was not a simple deist: the clockwork universe requires a Creator who made and sustains it; absolute space is the “sensorium” of God

References

• Mathematical Principles of Natural Philosophy (Philosophiae Naturalis Principia Mathematica, 1687) — mechanics, gravitation
• Opticks (1704) — light and colors
• Newton constructed no hypotheses (“Hypotheses non fingo”) — only laws verified by experience

General Philosophical Impact

General References

• Alexandre Koyré, From the Closed World to the Infinite Universe
• Alexandre Koyré, Galilean Studies
• Steven Shapin, The Scientific Revolution
• I. Bernard Cohen, The Newtonian Revolution
• Reale & Antiseri, History of Philosophy, vol. 3, ch. Scientific Revolution