Scientific Revolution and its Impact on Astronomy, Mechanics, Medicine, and Chemistry

1. Chapter 16 The Scientific Revolution

2. Background of the Revolution • Middle Ages - not a period of scientific ignorance • drawback to scientific research in Middle Ages: • Reliance on a small # of ancient authorities (Aristotle, Claudius Galen) • preferred logical analysis (theorization) to systematic observation • Renaissance humanists’ mastery of Greek unlocked new knowledge of Galen, Ptolemy, Archimedes, & Plato • showed that these unquestioned authorities of the Middle Ages were contradicted in their own times • led to exploration in those opposing theories • Renaissance artists also had an impact on scientific study • Accurate renderings of nature & human anatomy established new standards for study of natural phenomena • Artists were usually practicing mathematicians as well • Mathematics was seen as the key to understanding nature (The Golden Mean)

3. A Revolution in Astronomy & Mechanics • Cosmological view of late Middle Ages was a combination of Ptolemy, Aristotle & Christian theology • Result was Ptolemaic or geocentric cosmology (p.451) • This conception of the universe did not satisfy professional astronomers of the 16th century Nicholas Copernicus (1473-1543) • Accomplished mathematician and astronomer • 1506-30: worked on manuscript On the Revolution of the Heavenly Spheres, not published until 1543 • not great observational astronomer, but proved through data that Ptolemy’s system was incorrect • proposed a heliocentric universe, where the earth orbited the sun • Protestant reformers, including Martin Luther, denounced Copernicus & his theories

4. Tycho Brahe (1546-1601) • Copernicus did not have a great impact immediately, but doubts about Ptolemy were growing • a Danish nobleman, Brahe spent 20 years compiling data from his private observatories in his castle • Found enough information to discredit the geocentric model, but not enough to accept the Copernican concept of a moving earth • While living in Prague as imperial mathematician, took on an assistant named Johannes Kepler Johannes Kepler (1571-1630) • pushed by parents to become a Lutheran minister • real interests in mathematics & astronomy • theorized that the universe was constructed on the basis of geometric figures • Brilliant mathematician & astronomer, after Brahe’s death, succeeded him as royal mathematician for Rudolf II in Prague

5. developed three laws of planetary motion • orbits around the sun were elliptical w/ sun at focus not center • speed of a planet is greater near the sun & less farther away • planets w/ larger orbits revolve at slower velocity than those w/ smaller orbits • his laws disproved circular orbits, crystalline spheres, & the Ptolemaic system Galileo Galilei (1564-1642) • teacher of mathematics in Pisa • 1st European to observe the heavens by telescope (built himself) • showed that heavenly bodies were composed of matter similar to earth instead of ethereal, unchanging material • Publicly seen as a champion & hero of science, came under fire from the church • 1610 - The Starry Messenger, revealed him as a supporter of Copernicus’ heliocentric system, brought before the Inquisition • 1632 – Dialogue on the Two Chief Systems, brought before Inq.

6. 1633 – forced to recant his statements about the Copernican system, placed on house arrest, • studied mechanics in at his estate & tackled problems of motion • if uniform force applied to an object, it moves at accelerated speed, not constant speed • introduced concept of inertia, object in motion stays in motion unless acted upon by another force Isaac Newton (1642-1727) • invented calculus, investigated composition of light, & tackled concept of gravity • Principia – considered “hinge point of modern scientific thought” • every object stays at rest or uniform motion in straight line until deflected by a force • rate of change of motion proportional to force acting upon it • for every action there is an equal and opposite reaction • Universal Law of Gravitation every object in the universe is attracted to every other object with a force (gravity) directly proportional to the product of their masses and inversely proportional to the square of the distances between them • His “world machine” was the basis for scientific thought in the West until Einstein’s work with relativity in the 20th century

7. Advances in Medicine & Chemistry Paracelsus (1493-1541) • name means “greater than Celsus,” an ancient physician • seen by some as the father of modern medicine • vain, quick-tempered, not easy to get along with • hoped to replace the old system of Aristotle w/ new chemical philosophy • macrocosmic-microcosmic principle – the human being was a small replica of the larger world • argued disease was result of chemical imbalances localized in specific organs • believed in the ancient Germanic principle “like cures like” • seen as a “homicide physician” in his own time, looked at more favorably in later generations Andreas Vesalius (1514-1564) • 1543 - wrote On the Fabric of the Human Body • dissected cadavers in lecture to illustrate what he was discussing • disproved many of Claudius Galen’s errors, like the liver being origin of the blood vessels • still clung to the Galenic idea that two different types of blood flowed through veins & arteries

8. William Harvey (1578-1657) • 1628 – published On the Motion of the Heart and Blood • Although questions had been raised about Galen’s theories, no breaks from his system had arisen • through observation, Harvey proved • heart was the origin of blood not the liver • same blood flows in arteries & veins • blood makes a complete circuit as it passes through the body • 1660s - achieved general recognition w/ discovery of capillaries explained how blood got from arteries to veins Chemistry • science of Chemistry arose in the 17th & 18th centuries • Robert Boyle (1627-91) one of first to conduct controlled experiments • work with gasses led to Boyles Law (volume of a gas inversely proportional to pressure exerted on it) • proposed that matter is composed of “little particles of all shapes & sizes” (later known as chemical elements) • Antoine Lavoisier (1743-1794) invented a system of naming the chemical elements, regarded as father of modern chemistry

9. Women in the Origins of Modern Science Margaret Cavendish (1623-73) • aristocrat, participant in many crucial scientific debates • good example of French & English women involved in observational science, women often gravitated towards astronomy & entomology • between 1650 & 1710, 1 of 7 astronomers in Germany were women Maria Merian (1647-1717) • Worked in her father’s workshop, learned art of illustration (aided in observational sketches of plants & insects) • 1699 – traveled to Dutch colony of Surinam in S. America to study plant & insect life • led to her major scientific work, Metamorphosis of the Insects of Surinam Maria Winkelmann (1670-1720) • Most famous female German astronomer • Educated by her father & uncle, taught astronomy by her husband & became his assistant • After her husband died in 1710, applied for assistant astronomer at the Berlin Academy, but was rejected • because “mouths would gape” if a woman was hired

10. Descartes, Rationalism, & New View of Humankind Rene Descartes (1596-1650) • called the “Father of Modern Philosophy”, developed rationalism • his prime concern was to establish a criteria for defining reality • published works The Discourse on the Method (1637) & his Meditations (1641) contain a step-by-step account of how he arrived at his conclusions • 1st essential in the search for truth: refuse to believe anything that could not be undoubtedly proved to be true • basis of certainty from which he could build was: that he existed • very act of doubt proved he was a thinking being; summed up in his second Meditation: Congito ergo sum (I think therefore, I am.) • from that point Descartes was guided by the principle: whatever can be clearly perceived must exist • knew that perceptions could be misleading as to exact nature • perceptions only validate the simple existence of objects in question • concluded that God existed because as imperfect beings, we could not have imagined a perfect being unless it was based on reality

11. The Scientific Method Francis Bacon (1561-1626) • lawyer & lord chancellor of England • little scientific knowledge, rejected Copernicus, Kepler & misunderstood Galileo • developed a correct scientific method, built on inductive principles • urged scientists to proceed from particular to general • through organized experiments & systematic observation correct generalizations could be developed (empiricism) • Descartes believed that one could start with self-evident truths and deduce more complex conclusions • His emphasis on deduction and mathematical order complimented Bacon’s stress on induction and experimentation • Newton combined rationalist & empiricism to develop the scientific method • begins with systematic observations & experiments, used to arrive at general conclusions; • new deductions taken from general conclusions could then be tested and verified by experiments

12. Science & Religion • Galileo’s struggle w/ the church came from the fact that he did not see why the church tried to determine the nature of physical reality from scripture • the Church supported the Ptolemaic cosmology because it fit w/ philosophical views of reality • this conflict & rejection of Darwin’s theories in 19th century forever created a division between the scientific & religious communities Benedict de Spinoza (1632-77) • raised in Amsterdam, excommunicated from Amsterdam synagogue for rejection of tenets of Judaism at 24 • ostracized in both Jewish and Christian communities for his beliefs • rejected Descartes’s ideas about an infinite God and a finite universe • God is in everything so how can an infinite being “be” a collection of finite objects? • wrote Ethics Demonstrated in the Geometric Manner (p.468) to explain his position, not published until after his death

13. Blaise Pascal (1623-1662) • French scientist that sought to keep religion and science united • Accomplished scientist & brilliant mathematician • practical - built an adding machine • abstract – worked a great deal theorizing on probability & chance • wrote Pensees (Thoughts) but died before it was completed • Tried to convert rationalists to Christianity by appealing to their reason and emotion Man is but a reed, the weakest in nature; but he is a thinking reed. • Had answer for skeptics: God is a reasonable bet; it is worthwhile to assume God exists. If he does, then we win all; If he does not, we lose nothing.