Lecture: Science and Sentiment
Scientific Revolution
Lisa's definition of modern science: the combination of empirical and rational knowledge.
Ptolemaic-Aristotelian system
Before the scientific developments of the 17th century,
Europeans knew that the pattern of the 
universe
was based on the systems developed by the ancient astronomer
Ptolemy and the Greek philosopher Aristotle. This Ptolemaic-Aristotelian
system put the earth at the center of the universe, unmoving
and pulling heavy elements (earth, water) toward itself
and pushing light elements (air, fire) away. Surrounding
the earth were a series of concentric spheres made of
a fifth element called quintessence (that is, the
fifth essence). On these transparent spheres rested the
planets and stars. These spheres rotated around the earth
in predictable patterns, causing the rising and setting
of moon and planets, the movement of stars, and the paths
of comets and meteors.
Sound silly? Really? Tonight, if it's clear, go outside. Do the stars seem to move in groups? Do you feel the earth moving, or do you track the stars? Tomorrow, go to the beach. Does the sun set, or do you feel the earth rotate?
My point is, the system was based on empirical knowledge, that knowledge learned through your five senses (sight, smell, taste, hearing, touch). The knowledge you have that makes you think the earth rotates and revolves around the sun is rational knowledge. It was told to you by your culture, taught to you over and over. It's unlikely that you have empirical knowledge of the system, unless you've been up on a spacecraft.
The Ptolemaic-Aristotelian system worked fine for Europeans for centuries.
Copernican Theory
Then came Copernicus, a priest and mathematician. 
By
his time (the 16th century) earlier astronomers had added
many spheres to the original system to account for such
observations as retrograde motions and meteor paths. As
a mathematician, dedicated to reducing knowledge to quantifiable
terms, Copernicus found the system inelegant. He tried,
on paper, to reduce the number of spheres, to make the
system more efficient. He succeeded. His solution put
the sun at the center of the system, making a heliocentric
universe.
The Catholic Church, however, had long interpreted the Bible to mean that the earth was at the center of the universe. Copernicus reserved publication of his theory until his death, but so long as it was just presented as a theory, a hypothesis, a "what if", the Church had no problem. Astronomers found the system handy because it made their calculations more accurate.
What Copernicus had done, because he had never looked at the sky, was added the rational element to an empirical system.
Brahe, Kepler and Galileo
| Although he did not accept Copernican heliocentrism, Danish astronomer Tycho Brahe (d. 1601) created new instruments for studying the heavens and gathered a tremendous amount of data. He observed bodies and tracked the entirety of their orbits, bringing to light many inaccuracies and throwing wrenches into the works of 17th century astronomy. His observations of the birth of a star and a new comet challenged Aristotle's premise that the earth and the heavens were made of different substances, with the heavens being unchangeable. |  |
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Johannes Kepler began as an assistant to Brahe and later applied mathematics to Brahe's data. He was the first to develop the notion that planets moved in ellipses around Copernicus' heliocentric system. His three laws of planetary motion were later used by Newton. |
| Galileo developed the telescope using optical lenses available thanks to the technologies of Arab craftsmen. An Italian professor of mathematics, he studied motion and mechanics using experimentation, thus combining rationalism with empiricism. He created controlled reenactments of natural phenomena, such as rolling bronze balls down a smooth channel to measure acceleration. He developed the law of inertia, and thus destroyed the old concepts about heavy objects being in a natural state of rest. Through his telescope he saw other contradictions to prevailing theory, such as Jupiter's moons, which appeared to be rotating (against the rules) around a turning planet (also against the rules) and thus weren't on a known celestial sphere. |  |
So long as
Galileo was willing to present his findings as theories
rather than facts, the Catholic Church had no problem.
Overwhelmed by his new discoveries, and filled with the
knowledge he was right, Galileo began to publish his findings
as facts. Members of the scientific community were intrigued
by his work, but some were concerned about the ways in
which it contradicted the Bible, which presented a still
earth and the universe around it. The Grand Duchess Christina
was one such person, and Galileo's letter to her has been
taken as the ultimate break with the Church's view of
the heavens.
Workbook
document: Letter
to the Grand Duchess Christina (1615)
Galileo's publications led to arrest by the Papal Inquisition. When threatened with torture, Galileo agreed to recant his views as facts.
Newtonian synthesis
Englishman Isaac Newton is credited with putting together into one system the previous century's scientific achievements: Copernican mathematical simplicity + Brahe's massive collection of data + Kepler's elliptical orbits + Galileo's telescopic observations.. His combination of the experimental method with rational theory was seamless. His Mathematical Principles of Natural Philosophy (1687) broke new ground with some basic principles, including the idea that natural forces act in predictable ways. Of equal importance was the idea that there was no difference between celestial (heavenly) and terrestrial (earthly) physics. Therefore, experiments about the heavens could be conducted on earth.
But don't mistake Newton for a modern scientist. He also believed in alchemy to turn metal into gold.