HSCI 224: Cohen Reading Guide

Reading Guide:

I.B. Cohen, Birth of a New Physics

Chapter:

Chapter 1, "The Physics of a Moving Earth"

3.	What does the claim that "to be ignorant of motion is to be ignorant of nature?" do?
8.	[Research] Why does a heavier object fall faster than a lighter one of the same material and shape?
8.	Why does a rotating and revolving earth require a new physics?
10.	Why aren't we aware of a velocity as large as 19 miles/second?

Chapter 2, "The Old Physics"

12.	What are some of Aristotle's achievements?
13.	What's the natural motion of an unimpeded terrestrial object?
14.	What's the natural motion of a celestial object?
13/14.	What is violent motion?
15.	What is "local motion"?
15.	For motion, what is the 1st principle?
17.	For bodies of = weight, how does speed relate to resistance?
19.	What is Aristotle's Law of Motion? Why didn't he use equations?
19/20.	What are some of the defects of Aristotle's Law of Motion?
21.	If V=F/R didn't work in air, why did it persevere? No one noticed?

Chapter 3, "The Earth and the Universe"

24.	Besides DeRev, what other significant scientific work was published in 1543?
25.	Does Cohen think Copernicus a conservative or a revolutionary?
28.	On what basis did Hipparchus say the sun appeared to move with variable velocity?
29.	What does "save the appearances' mean? [here, the context is limited]
30.	Was it widely known that the Ptolemaic system was difficult to understand? In which sense, cosmological or mathematical?
42.	Discuss: Did Copernicus' system have any more information about distances than was given in the ratio of radii of deferent and epicyle in Ptolemaic astronomy?
44.	Why does Cohen say it's preferable to call the Copernican System heliostatic in place of heliocentric?
45.	What were the chief advantages of the Copernican system?
45f.	What were the chief disadvantages?
51.	For Cohen, what problems with Copernicanism were there apart from just the astronomical considerations?
52/53.	For Cohen, in what can the unity of science best be seen?
53.	If not Copernicus', whose was the Copernican Revolution? [Why?]

Chapter 4, "Exploring the Depths of the Universe"

54.	Why does Cohen believe that 1609 overshadows 1543 in the history of astronomy?
55.	[Your guess] How old on average are the discovers/inventors of profoundly significant scientific discoveries?
57.	Why is Galileo given the credit for first using the telescope for astronomical purposes when he wasn't the first? And why should credit matter?
58.	In what sense does Cohen view 1609 as an epiphany for Galileo?
58-62.	What is most striking about Galileo's treatment of the lunar landscape?
61.	What feats of the imagination are required to measure the heights of lunar mountains?
61.	[Research/Thought] How careful do observations have to be? Why can't one use the lengths of shadows cast by the mountains to calculate their heights?
63.	What was the significance of earth shine?
64-71.	What were some more of Galileo's significant observations in Sidereus Nuncius [March 13, 1610]?
74.	Why were the phases of Venus a decisive blow to Ptolemaicism?
74.	What other significant observations did Galileo make?
75-79.	What sorts of reactions were there to the publication of Galileo's telescopic discoveries?

Chapter 5, "Toward an Inertial Physics"

UNIFORM LINEAR MOTION

82.	What did Two New Sciences contain?
85.	Is it actually true that "an object falls to the same spot . . the foot of the mast?

GALILEO'S SCIENCE OF MOTION

85.	What were the 3 major aspects of G's work on motion?
86.	Who, before Galileo, had shown that everything in Aristotle's physics was unscientific? Showing?
87.	How does Galileo describe his "odd-integer rule?"
88.	How does Galileo phrase a metaphysical equivalent of Ockham's Razor [see page 127, also]
90/91.	[Research/Calculation] What interesting error did Galileo make in writing to Sarpi?
91.	Is Proposition I, Theorem I Galileo's creation? [see page 102]
94.	How does Galileo's procedure with the inclined plane differ from the common textbook portrayal of "the scientific method?"
96.	What is the particular genius of Galileo's using an inclined plane to model free fall?
98.	What was the inclined plane experiment for?
100.	What, to Galileo, was to be done if a logically valid theory contradicted sensory evidence?

GALILEO'S PREDECESSORS

103.	What distinguishes 14th century scholastics from Galileo?
106.	What did Galileo do that was original about motion?

FORMULATING INERTIA

107.	Why does a projectile follow a parabolic path?
112.	Why does Cohen argue that the path of a stone dropped from a tower is parabolic?
112.	Why is the resolution of motions into separate orthogonal components a measure of the genius of Galileo?

DIFFICULTIES AND ACHIEVEMENTS: LAW OF INERTIA

119.	Was Galileo's inertia rectilinear or circular, or both?
121.	Why would G. have objected to Newtonian inertia?
122.	By when had Galileo formulated an idea of a kind of inertia [1st quasi-modern statement of the principle] and how do we know?
124.	Why does Cohen believe Galileo "a creature of his time?"
125.	How did Newton and Huygens differ from Galileo concerning circular motion?
125.	What does Cohen think led to Galileo's battle with the Church?

Chapter 6, "Kepler's Celestial Music"

127.	State Occam's Razor, or the Principle of Parsimony. Is it methodological or metaphysical?

THE ELLIPSE AND THE KEPLERIAN UNIVERSE

131.	Did Newton read Kepler's astronomical work?
132.	In what tradition was Kepler rooted? and -- 132ff:
132ff.	How does Cosmographicum Mysterium illustrate your answer?
134.	Is it really true that Brahe's observations made it clear that neither the Ptolemaic, nor Copernican systems could "truly predict the celestial appearances"?
135.	Who first discovered, after Tycho's death, that perhaps Tycho's observations invalidated the Ptolemaic, Copernican, and Tychonic systems as true predictors of celestial phenomena?

THE THREE LAWS

137.	Why did Kepler have to determine the earth's orbit as well as Mars?
138.	What are Kepler's three laws?
140.	What is an astronomical unit?

KEPLER THE COPERNICAN

142.	Did Galileo formally acknowledge Kepler's work?
144.	What is an anima motrix?
145.	[Research] Can you suggest why Galileo especially chastises Kepler for Kepler's emanation theory about tides?
145.	How many satellites does Mars have?
147.	Kepler could answer why there were only 6 planets. Can we answer why there are only 9?

Chapter 7, "The Grand Design - A New Physics”

148.	Why does Cohen think Newton's was a "fantastic scientific achievement"?
150.	By when had Halley concluded that the force driving planets was an inverse square force? [Research: Newton?]
152.	[Opinion] Why doesn't Cohen present Law III?
152.	Who first published "Newton's" first Law? before what date?
155.	How did Newton's Law II amend Aristotle's v ? F law?
156.	What new concept is implicit in Law II?
158.	What does Newton's examination of F ? D tell us about Newton?
159.	Does experience ever show us "pure inertial motion"?
161.	How does the first theorem of the Principia relate to Kepler?
164.	What is Newton's masterstroke?
165.	Who first published the measure of the centripetal acceleration involved in circular motion?
165/171.	What is the significance of the "apple" for Newton?
173.	Why did Newton say his test observation agreed only "pretty nearly"?
175.	[Calculation] If you moved to the equator, how much weight would you lose?
176.	What is the precession of the equinoxes, and how does it make itself known?
176.	[Research] Why is this the "dawning of the Age of Aquarius"?
178/180.	What is the law of the conservation of angular momentum?
181/182.	Is the framework of the Newtonian system still as valid as Newtonian mechanics? What word[s] might Kuhn use in place of "framework"?
182.	"The greatest achievement of Newtonian science" is?
183.	What promise did Newtonianism hold out?
184.	What, above all, do we see in Newton's work?
184.	[Opinion] Do you agree that "pure science exemplifies the creative accomplishment of the human spirit at its pinnacle"?

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