The Scientific Revolution. Ptolemaic View of the Universe For centuries, Europeans believed that the Earth was at the center of God’s universe and that.

The Scientific Revolution

Ptolemaic View of the Universe• For centuries, Europeans

believed that the Earth was at the center of God’s universe and that the heavenly bodies orbited the Earth in perfect circles (the “Heavenly Spheres”)

• This geocentric (Earth-centered) model had been put forth by the Roman scientist Ptolemy in the 2nd century AD

Nicolaus Copernicus• 1473 – 1543• Catholic Polish astronomer• His observations led him to

challenge the geocentric model and propose a heliocentric (sun-centered) model

• Also argued that the Earth revolved on an axis and took 365 days to orbit the sun

• Published On the Revolutions of the Celestial Spheres (1543) in the same year that he died

• His work was attacked by Luther & other Protestants, but not by the Catholic Church

Tycho Brahe• 1546 – 1601• Wealthy Danish nobleman• Built a personal observatory

and charted 20+ years worth of careful records on celestial motions

• Lost his nose in a duel, so he wore false metal ones

• Hired a young assistant named Johannes Kepler to help record data

Johannes Kepler• 1571 – 1630• German astronomer &

teacher• Used Brahe's data to argue 3

laws of planetary motion: orbits of planets are elliptical; planets speed up as they get closer to sun; planets with larger orbits revolve slower than those with smaller orbits

• Improved the telescope• Faced persecution and ridicule

due to his Calvinist faith

Galileo Galelei• 1564 – 1642• Italian scientist• Proved that the Earth revolves around the

sun in his work, The Starry Messenger (1610) • Catholic Church condemned Galileo's work –

argued he should focus "not how the heavens go, but how to go to heaven"

• Galileo again upset the Church by continuing to argue heliocentrics in Dialogue on the Two Chief World Systems: Ptolemaic and Copernican (1632)

• In 1633, facing the Inquisition, Galileo recanted his findings and was placed under house arrest until his death

• Continued to work, even under house arrest, on "mechanics" (inertia, acceleration)

Heliocentric Theory• Despite the Church’s

protests, Galileo was too well respected as a scientist to be ignored and Europe’s educated elite quickly adopted his heliocentric model for the universe

• It’s worth noting, however, that Galileo and his predecessors were still WRONG – the Sun is not the center of the universe

Sir Francis Bacon• 1561 – 1626• English nobleman and former Lord

Chancellor of England who was forced out of politics due to numerous scandals

• Became a scientist, but discovered that there was no standard system for approaching experimentation

• Began to develop a scientific method for conducting empirical (observation-based) research

• Believed that science should serve and empower man, be practical, help man conquer nature

• Many unanswered questions about Bacon: Was he Elizabeth I’s secret son? Was he the real author of Shakespeare’s plays? Was he a homosexual?

Rene Descartes• 1596 – 1650• French philosopher and

mathematician; father of modern rationalism (thought-based, or deductive, research)

• “Cogito ergo sum” (I think, therefore I am) - Descartes only believed in things that his mind could accept as true

• Cartesian dualism – the mind is immaterial and completely separate from the material body

• Also developed the Cartesian plane and Cartesian coordinate system, critical to the development of higher math such as calculus

The Cartesian Coordinate System

Sir Isaac Newton• 1642 - 1727• English scientist, devout Christian• Wrote Principia Mathematica

(1686) in which he explained his three laws of motion: an object in motion tends to stay in motion unless affected by an outside force; change in motion is proportional to force; for every action, there is an equal and opposite reaction

• Newton used these laws to explain gravity - a universal force that describes all motion in the universe

• In order to mathematically explain motion and gravity, Newton created the new field of calculus

Sir Isaac Newton• Newton also discovered the

composition of light and made major improvements to the telescope

• Newton saw his discoveries as reinforcing the existence of God, because only a Supreme Creator could have set such physical laws in motion

• Still, even Newton wasn’t perfect – he wasted much of his time studying alchemy, magic, astrology, and apocryphal writings

Newton’s Light Experiment

Scientific Method• Bacon's empiricism

(observational experimentation) + Descartes rationalism (deductive reasoning) + Newton's practical application of each = The Scientific Method

Robert Boyle• 1627 – 1691• Irish chemist• Boyle’s Law: When

temperature is held constant, pressure is inversely related to volume in gases

• Advanced the idea that matter is made up of atoms

Boyle’s Law

Antoine Lavoisier• 1743 – 1794• French nobleman and

chemist• Developed the first system

for identifying and naming chemical elements

• Created the metric system of measurements

• Executed during the French Revolution

Paracelsus• Actual name: Philippus Aureolus

Theophrastus Bombastus von Hohenheim

• 1493 – 1541• Swiss doctor• Determined that disease is caused

by chemical imbalances in specific organs and can be countered with carefully dosed chemical remedies

• Argued that often “like cures like” – (ex. fight fever by keeping the patient warm)

• First to diagnosis specific illnesses and prescribe specialized treatments

Andreas Vesalius• 1514 – 1564• French doctor• Wrote On the Fabric of the Human

Body (1543), an advanced study of human anatomy; Vesalius dissected the corpses of executed criminals and used professional artists to illustrate his book

• Became the imperial physician to both Charles V and his son Philip II of Spain

• Despite the new knowledge he had gained, Vesalius still held to many ancient medical practices, such as bloodletting, to sure illnesses

On the Fabric of the Human Body

William Harvey• 1578 – 1657• English doctor• Wrote On the Motion of the

Heart and Blood (1628)• Discovered that it is the heart,

not the liver, which is the vital force in blood flow; also determined how blood flows through veins and arteries

• Personal physician to Kings James I and Charles I, as well as Francis Bacon

Benedict de Spinoza• 1632 – 1677• Dutch Jew, but

excommunicated by the Judaic church

• Argued that God is nature and therefore everything is subject to natural laws

• This means everything has a rational explanation which can be discovered and understood

• Believed science had no limits

Blaise Pascal• 1623 – 1662• French mathematician, scientist, and

religious philosopher• Pointed out the limits of science• Argued that humans are deceived by

their senses (so no empiricism), misled by reason (so no rationalism), and are controlled by their emotions

• We can never prove or disprove the existence of God – we can’t see God, we can’t rationalize God – so we must rely on faith

• “God is a reasonable bet; it is worthwhile to assume God exists. If He does, then we all win; if he does not, we lose nothing.”