The Scientific Revolution (1500s-1700s)

What was the Scientific Revolution? Beginning of modern science Scientific method: Depends upon logic, observation, and reason rather than faith Created the technologies and techniques that built the modern world Created paradigm of our solar system

Revolution in Epistemology and Philosophy Universities formed Rediscovery of classical science Leading figures Bacon Brahe Copernicus Descartes Galileo Kepler Newton

Nicolaus Copernicus (1473-1543) Earth revolves around the sun Book On the Revolutions of the Heavenly Spheres Heliocentric theory: Sun is the center of the universe

Tycho Brahe (1546-1601) Danish royal astrologer Follower of Ptolemaic system Observed and mapped over 700 stars in a 20-year period

What did Brahe place an emphasis on? “To deny the power and influence of the stars is to detract from divine wisdom and influence. What more prejudiced or what sillier thought could one have about God than that He had made the most enormous and extraordinary of all heavens and a theatre of so many shining stars in vain and to no useful purpose, when no human being does even the most worthless task except for a particular purpose?” Tycho Brahe, De disciplinis mathematicis oratio, 1574

Sir Francis Bacon (1561-1626) Preferred inductive reasoning and facts over theory Invented the scientific method

Galileo Galilei (1564-1642) “I recant” Invented the pendulum clock, thermometer, water pump, and sector Created his own telescope based on another model Discovered speed of acceleration for gravity

Johann Kepler (1571-1630) Brahe’s student for 20 years Living during 30 years of war Loved the planets and made it his life’s work to explain the motion of planets Invented Three Laws of Planetary Motion Included religious arguments and reasoning into his work God’s geometrical plan for the universe?

What scientific theory did Kepler support? “ Firstly, therefore, let my readers grasp that today it is absolutely certain among all astronomers that all the planets revolve around the sun, with the exception of the moon, which alone has the Earth as its centre: the magnitude of the moon’s sphere or orbit is not great enough for it to be deliniated in this diagram in a just ratio to the rest. Therefore, to the other five planets, a sixth, Earth, is added, which traces a sixth circle around the sun, whether by its own proper movement with the sun at rest, or motionless iself and with the whole planetary system revolving.” Johannes Kepler, Harmonices Mundi (The Harmonies of the World), 1619

Rene Descartes (1595-1650) Deductive logic Deduced the existence of God Invented Cartesian geometry (xy axis) “I think therefore I am” Perception is unreliable- deduction is only tool

How does Descartes describe the ‘laws of nature’? “Note, in the first place, that by ‘nature’ here I do not mean some goddess or any other sort of imaginary power. Rather, I am using this word to signify matter istelf, in so far as I am considering it taken together with all the qualities I have attributed to it, and under the condition that God continues to preserve it in the same way that he created it. For it follows of necessity from the mere fact that he continues thus to preserve it, that there must be many changes in its parts which cannot, it seems to me, properly be attributed to the action of God (because that action never changes), and which therefore I attribute to nature. The rules by which these changes take place I call the ‘laws of nature.’” Rene Descartes, The World, 1664

Who does Descartes ultimately trust? “Nevertheless, mindful of my own weakness, I make no firm pronouncements, but submit all these opinions to the authority of the Catholic Church and the judgment of those wiser than myself. And I would not wish anyone to believe anything except what he is convinced of by evident and irrefutable reasoning.” Rene Descartes, Principles of Philosophy, 1644

Sir Isaac Newton (1642-1727) The Principia Tied up the loose ends of Kepler and Galileo Three Laws of Motion Defined gravity and its laws Invented optics and calculus Royal Society

What scientific principle is Newton describing? “Then the motions of the planets, the comets, the moon, and the sea are deduced from these forces by propositions that are also mathematical. If only we could derive the other phenomena of nature from mechanical principles by the same kind of reasoning! For many things lead me to have a suspicion that all phenomena may depend on certain forces by which the particles of bodies, by causes not yet known, either are impelled toward one another and cohere in regular figures, or are repelled from one another and recede.” Isaac Newton, Mathematical Principles of Natural Philosophy (Principia), 1687.

What is the “divine arm” in the passage below? “In my former I represented that the diurnal Rotations of the Planets could not be derived from Gravity, but required a divine Arm to impress them. And tho’ Gravity might give the Planets a Motion of Descent towards the Sun, either directly or with some little Obliquity, yet the transverse Motions by which they revolve in their several Orbs, required the divine Arm to impress them according to the Tangents of their Orbs.” Letter from I. Newton to R. Bentley, 11 February 1693, Isaac Newton’s Papers and Letters on Natural Philosophy and Related Documents

Rise of the Scientific Community Developed the modern scientific method Universe ordered according to natural laws Discovered that scientific laws can be discovered by human reason Took the role of a deity or god out of the study of the universe Mechanical views of the universe Deistic view of God

Review Questions Describe the Scientific Revolution. What astronomer, author of On the Revolutions of the Heavenly Spheres, believed that the earth revolves around the sun? Who is credited with inventing the scientific method? Who came up with the Three Laws of Planetary Motion? What famous Italian astronomer was convicted of heresy by the Inquisition? What English scientist defined gravity?