The Scientific Revolution

What Was the Scientific Revolution? A revolution in human understanding and knowledge about the physical universe 17th century Began with Kepler, Galileo Ended with Newton

“Science” Before the Scientific Revolution Based almost entirely on reasoning Experimental method or observation wasn’t used at all Science in medieval times Alchemy Astrology A medieval alchemist

Factors Leading to the Scientific Revolution Rise of universities Contact with non-Western societies The Renaissance Exploration

Rationalism Reason, not tradition, is the source of all knowledge René Descartes (1596–1650) French philosopher and mathematician Cogito ergo sum (“I think, therefore, I am”) Deductive reasoning René Descartes

The philosophy of rationalism holds that all knowledge comes from reason. René Descartes was one of the most important philosophers and mathematicians of his time; many regard him as the father of modern rationalism. In Discourse on Method and The Meditations, he reasoned that all of his prior knowledge was subject to doubt because it was based on traditional beliefs rather than on reason. He pondered what he could honestly say he knew to be true, going so far as to doubt whether he was awake or dreaming—or if he even existed. He then began to reconstruct his world view: he knew that his thoughts existed, which then suggested the existence of a thinking being—himself. Descartes then came to his famous conclusion, “Cogito ergo sum,” which means “I think, therefore, I am.”

Empiricism The belief that experience is the only true source of knowledge Roger Bacon Shift toward empiricism a hallmark of the Scientific Revolution Helped lead to the development of the scientific method Roger Bacon

Francis Bacon and the Scientific Method 1561–1626 English philosopher and empiricist Inductive reasoning Argued for experimental methodology

English philosopher Sir Francis Bacon laid the theoretical groundwork for what became known as the scientific method. His ideas about science incorporated what is known as inductive reasoning, which involves using concrete facts to extrapolate broader conclusions. (Inductive reasoning is the opposite of deductive reasoning.) Bacon argued that scientists should work from the specific (observable data) to the general (rules and theories based on that data). He believed that all scientific research should rely on careful observation and experimentation rather than simply relying on one’s own thought and reasoning, as earlier scientific thinkers had. The data obtained should then be recorded and analyzed according to logic and reason, then used to produce a testable hypothesis.

The Scientific Method Science as a multiple-step process: 3. Test the theory with experiments 2. Develop a theory that explains the object or phenomenon 1. Observe an object or phenomenon

Roots of Scientific Thought: Aristotle 4th century BCE Greek philosopher and scientist Wrote several scientific works His work laid the foundation for scientific study through the medieval era Gravity/Theory of falling objects Astronomy: Crystal spheres

Roots of Scientific Thought: Ptolemy 2nd century CE Greek astronomer, mathematician, and geographer The Almagest (Syntaxis) Geocentric (earth-centered) model of the universe Motion of the planets

Models of the Universe: Geocentric vs. Heliocentric Geocentric: the Earth is at the center of the universe; all heavenly bodies move around the Earth Heliocentric: the Sun is at the center of the universe; all heavenly bodies move around the Sun—including the Earth

Nicholas Copernicus (1473–1543) Polish astronomer and mathematician Commentariolus (1514) Concerning the Revolutions of the Celestial Spheres (1543)

Johannes Kepler (1571–1630) German astronomer and mathematician Student of Tycho Didn’t agree with Tycho’s interpretation of data Disagreed with Copernicus, claiming that other bodies moved in elliptical motion, as opposed to circular motions Theorized three laws of planetary motion using Tycho’s data

Galileo Galilei (1564–1642) Italian mathematician, astronomer “Father of Science” Telescopes and astronomical discoveries Theory of falling objects; disproved Aristotle Galileo’s telescopic drawing of the moon

Galileo vs. the Catholic Church The church condemned heliocentric conceptions of the universe The Roman Inquisition Galileo’s trial Galileo recants, put under house arrest 19 th -century depiction of Galileo before the Inquisition tribunal

Using his pulse while watching a lamp swing in a cathedral, Galileo developed the Law of Pendulum which was used to build clocks.

 Bored with college, he dropped out and was tutored to satisfy his thirst for mathematics.  He was later offered a teaching position at the University and began tutoring students and continuing his experiments.  Galileo questioned the laws of nature accepted from Aristotle which stated that larger objects would fall faster than lighter ones.

Galileo climbed to the top of the Tower of Pisa to do his experiments. He lost his teaching position when he became too arrogant with his findings.

Early Spyglass (Later renamed the telescope)

New Telescope Discovers  Moon is an irregular, rough body, not smooth as previously thought.  Milky Way is composed of many stars.  Jupiter has many small satellites he called “Sidera Medicea” after his favorite student.  Made observations about Saturn, sunspots, and the phases of Venus.

Sunspots Observations (1612)

In 1613, Galileo stated the earth traveled around the sun, which contradicted the teachings of the church.

On March 5, 1616, the Catholic Church declares the writing of Galileo banned. He retires to his home near Florence, Italy. He continues his writings and observations.

The Pope begins to find fault in all of Galileo’s writings and in February, 1633, Galileo is charged with “vehement suspicion of heresy” and tried. He is placed under house arrest until his death eight years later.

The church finally lifted the ban on Galileo’s writing in 1822, accepting that the Sun, not the earth, was the center of the known Universe.

Finally, in 1992, three years after Galileo’s namesake had been launched on its way to Jupiter, the Vatican formally and publicly cleared Galileo of any wrongdoing.

Sir Isaac Newton (1642–1727) English astronomer, physicist, and mathematician Synthesized the works of Copernicus, Kepler and Galileo The Principia

Considered by many to be the greatest figure of the Scientific Revolution, Newton synthesized the works of Copernicus, Kepler, and Galileo in formulating his theories on gravity and motion. After decades of research, he presented the foundation of these theories (along with other observations concerning mathematics and geometry) in the Principia, perhaps the most influential science book ever written. The Principia presented a new view of the world, one expressed in entirely mechanical terms, with Newton portraying the universe as a large clock that operated by a consistent set of rules. The book was well received by the academic community of Europe at the time and his new world view became the accepted paradigm until the atomic age. Legend holds that Newton “discovered” gravity when an apple fell on his head from a nearby tree, although many believed Newton—who loved to tell stories—made the whole thing up.

The Significance of the Scientific Revolution Abandonment of ancient and medieval systems Development of the scientific method The Enlightenment