Astronomy, New Philosophy, and Galileo

1. The place of physics and astronomy in Scholasticism (1500s – 1600s)

   •   idealized, mathematical Ptolemaic model (Ptolemy’s Almagest):

     •  “saving the phenomena” and mathematical models

     •  celestial spheres: geometric techniques, epicycles, eccentrics

     •  dilemmas of model not fitting observations [retrogression of Mars]

     •  lack of unity with Aristotelian philosophy

   •  problems for orthodoxy

     •   calendar and other technical problems (Papal Commission for reform of the calendar)

     •   Reformation & Counter-Reformation (Council of Trent)

   •  Copernicus’s On the Revolutions of the Heavenly Spheres (1543):

     •   the argument for heliocentrism, summarized in the “Preface”:

       •   ancient authority

       •   the new model’s accuracy

       •   restoration of systematic coherence

       •   Hermetic appeal to the role of the sun

   •  the reaction to Copernican theory

     •   a model for computation, as stated in the anonymous Foreword

     •   questions of accuracy and technique in the Copernican model

     •   the physical problem of an earth in motion

     •   Tycho’s new accuracy and alternative model

   •  Kepler’s new model and causes (1595-1608):

     •   ideal, mathematical harmony

     •   elliptical solution for orbits

     •   new physical explanations and anima motrix

2. Galileo’s new physics of motion and substance (1590s-1620s)

   •   rejection of Aristotle

   •   the new use of Archimedes’s mechanics

   •   new geometrical, diagrammatic techniques of analysis: abstract idealization of problems

   •   quantitative measurement of physical properties

   •   emphasis on dimension, distance, time, and the role of mathematics

   •   rejecting causal qualities and “forces”

   •   empirical investigations and inventions:  “Measure all things, and make measurable what is not.”

   •   physics and mathematical demonstrations in The Assayer (1623)

3. Supporting Copernicus with new physical evidence (1610s)

   •   Tycho’s measurements of comet and supernova

   •  Galileo’s telescope observations and Starry Messenger (1610):

     •   rhetoric and style of his demonstration

     •   new evidence for the physical nature of moon, planets, heavens

     •   contradictions with orthodox model

     •   Jupiter as a center of motion for its satellite moons

     •   persuasiveness and celebrity

   •   the phases of Venus

4. Galileo’s political and legal support and troubles

   •   life as a courtier

   •   his defense of his views, as explained in “Letter to the Grand Duchess Christina of Tuscany” (1615)

   •   the 1616 ban on Copernican astronomy

   •   Galileo’s Dialogue concerning the Two Chief World Systems (1632):

     •   rhetoric of Galileo’s presentation

     •   trial:   Admonition and violation, Sentence, and Abjuration

5. Galileo’s unification of earthly and celestial physics

   •   uniform circular motion

   •   argument for inertia and relative motion

   •   Discourses and Mathematical Demonstrations concerning Two New Sciences (1638)

   •   new method for physics:

     •   empiricism, experimentation, and demonstration

     •  natural experiments of confirmation

     •   the language of mathematics and “the book of nature”

     •  simple mechanical interpretation and language, in opposition to qualities

© 2018 Dr. William Kimler