Jonathan Bain
Humanities and Social Sciences
Polytechnic Institute of New York University

PL 2094 - Space and Spacetime
[Home]
[Syllabus]
[Study Questions]
[Paper Topics]
[Paper Guidelines]

Plato Links: Study questions on Plato (Timaeus and commentary - Huggett, Chapter 1)
1.
What are the three types of things that Plato mentions?
2.
Why must the thing upon which the imprints are to be formed be totally devoid of any characteristics?
3.
Which of the three things mentioned in (1) does Plato identify with space?  (Note:  the reading has been edited in a slightly misleading way here.)
4.
What are some characteristics of space, according to Plato?
5.
According to Plato, can space act on physical objects?
6.
How does Huggett define a valid argument?
7.
What is Huggett's definition of a scientific theory?  According to Huggett, what makes a theory good?

Euclid Links: Study questions on Euclid (The Elements and commentary - Huggett, Chapter 2)
1.
How does Euclid define a point?  A line?  A right angle?
2.
What are Euclid's five postulates?
3.
According to Postulate 32,  the interior angles of any triangle are equal to what?
4.
What does it mean to say that a line is a dense collection of points?
5.
How can Euclidean geometry be thought of as a theory of space?  In what sense can it immediately be said to be a "good" theory of space?
6.
How can Gauss' Experiment be thought of as a confirmation of Euclidean geometry thought of as a theory of space?  Suppose you think Euclidean geometry is not true of the actual world.  How could you respond to the outcome of Gauss' Experiment?

Study questions on Zeno (Huggett, Chapter 3)
1.
Describe Zeno's first argument against the possibility of motion (the Dichotomy argument).
2.
According to Aristotle, what are the two ways in which a time interval or a line segment can be infinite?
3.
How does Aristotle use the distinction made in #2 as a response to Zeno's first argument against the possibility of motion?  Why does Aristotle think this is not an adequate response?
4.
How does Aristotle argue for the possibility of having a finite length of time composed of an infinite number of time intervals?
5.
Describe Zeno's "Achilles" argument against the possibility of motion.
6.
According to Zeno, why is a flying arrow motionless?  Why does Aristotle think this is false?
7.
Describe Zeno's fourth argument against the possibility of motion.  (Note:  the translation is a bit misleading.)
8.
Describe the argument Zeno gives against plurality (Fr. 13).
9.
Which premise in Huggett's reconstruction of the Dichotomy argument can we reject without having to reject Euclidean geometry?
10.
What is Cauchy's definition of an infinite sum?  How does this resolve the Dichotomy argument?
11.
Why can't we use Cauchy's definition of an infinite sum to conclude that the length of a line segment comprised of dimensionless points is zero?
12.
Why can't the length of a finite line segment depend on the number of points that make it up?
13.
According to Huggett's reconstruction of Zeno's Arrow Paradox, why is motion during an instance impossible?
14.
How does the "at-at" theory of motion reconcile the claim that motion during an instance is impossible with the claim that motion in general is possible?
15.
At any given instant t, how can the "at-at" theory of motion distinguish between an arrow in motion versus an arrow at rest?

Study questions on Aristotle (Physics, On the Heavens - Huggett, Chapter 4)
Physics
1.
What two reasons does Aristotle give for why the concept of place is so important?
2.
Why does Aristotle think the place an object occupies must be different from the object itself?
3.
In what way does place exert an influence on objects?
4.
According to Aristotle, in what sense could place be the form of an object?  In what sense could place be the matter comprising an object?
5.
Why does Aristotle think place cannot be either the form or the matter associated with an object?
6.
Why does Aristotle think place cannot be the "extension between the extrimities" of an object?
7.
What, finally, does Aristotle take place to be?
8.
What does it mean to say that the place of a thing is the "innermost motionless boundary" of what contains it?
9.
According to Aristotle, why does the World have no place
On the Heavens
10.
Why does Aristotle think there cannot be a fourth dimension?
11.
According to Aristotle, what movements constitute simple locomotion?
12.
What two simple bodies move by nature away from the center?  What two simple bodies move by nature toward the center?
13.
Why must there be, in addition to the four simple bodies in #12, a fifth simple body whose natural motion is in a circle?
14.
Why is the fifth simple body whose natural motion is in a circle "more divine and prior to" the other four simple bodies?
15.
According to Aristotle, why can't there be more than one World?
16.
Why does Aristotle claim there is no such thing as infinite (i.e., unlimited) motion?
17.
According to Aristotle, why is the world (i.e., the universe) spherical and not egg-shaped?
18.
According to Aristotle, why is the Earth motionless and at the center of the universe

Study questions on Descartes (Principles of Philosophy and commentary - Huggett, Chapter 4)
1.
Why don't we have to worry about being decieved by "clear and distinct" perceptions, according to Descartes?
2.
What is the essence of corporeal substance?  What is the essence of thinking substance?
3.
Is there a difference between an extended body and an extended space, according to Descartes?
4.
Why does Descartes think that, in relation to different bodies, we may say that the same thing is both changing and not changing its place at the same time?
5.
What is the distinction between "internal place" and external place", according to Descartes?
6.
What do variation and diversity in matter depend on?
7.
How does Descartes define "motion"?
8.
Does Descartes think it takes more action to move a body than to keep it at rest?
9.
What is Descartes' first law of motion?
10.
How does Descartes' first law of motion resolve Aristotle's problem of describing projectile motion?
11.
What is Descartes' second law of motion?
12.
How does Descartes avoid Aristotle's objection to the identification of place with matter?

Study questions on Newton (De Grav and Principia - Huggett, Chapter 5)
De Gravitatione
1.
Why is the tendency of the Earth to recede from the Sun hard to explain on Descartes' relational theory of motion?
2.
According to Newton, how can the following two situations be distinguished?  (a) Earth at rest and stars revolving around the Earth; (b) Earth rotating on its axis and stars at rest.
3.
According to Descartes, can the two situations in #2 be distinguished?
4.
Why does Newton think that, on Descartes' account of motion, a moving body has no determinate velocity and no determinate line in which it moves?
5.
For Newton, are body and extension identical?
6.
What are some characteristics of extension (i.e., space), according to Newton?
7.
Why does Newton claim that the parts of space are motionless?
8.
What does Newton mean when he says, "Whatever is neither everywhere nor anywhere does not exist"?
Principia
9.
How does Newton define absolute time?
10.
How does Newton define absolute space?
11.
How does Newton define place?  How does this differ from the accounts of Plato, Aristotle and Descartes?
12.
How does Newton define absolute motion?
13.
According to Newton, how can we distinguish absolute rest and motion from relative rest and motion?
14.
What are the causes by which true and relative motions can be distinguished?
15.
What does Newton's bucket experiment demonstrate?
16.
Why are true motions difficult to distinguish from apparent (relative) motions?
17.
What does Newton's globes experiment demonstrate?

Study questions on Leibniz and Clarke (The Leibniz-Clarke Correspondence - Huggett, Chapter 8)
1.
What is Leibniz's Principle of Sufficient Reason?
2.
What is space, according to Leibniz?
3.
According to Leibniz, how would the existence of absolute space violate the Principle of Sufficient Reason?
4.
How does Clarke respond Leibniz's "Static Shift" argument described in #3?
5.
How do Clarke and Leibniz differ over what the Principle of Sufficient Reason entails about God's actions?
6.
What is Leibniz's Principle of the Identity of Indiscernibles?
7.
According to Leibniz, how would the existence of absolute space violate the Principle of the Identity of Indiscernibles?
8.
Leibniz considers the following claim:  "God can cause the whole universe to move forward in a right line, or in any other line, without making otherwise any alteration in it."  Why does the existence of absolute space entail this claim?  Why does Leibniz think that this claim violates the Principle of Sufficient Reason?  Why does he think it violates the Principle of the Identity of Indiscernibles?
9.
Why does Clarke disagree with the Principle of the Identity of Indiscernibles?
10.
According to Clarke, does a motion have to be observed in order to be real?
11.
What type of motion of the universe does Clarke think would be discernible and thus would not violate the Principle of the Identity of Indiscernibles?
12.
According to Leibniz, does a motion have to be observed in order to be real?
13.
According to Leibniz, how is absolute true motion distinguished from relative motion?

Study questions on Berkeley and Mach (De Motu and The Science of Mechanics - Huggett, Chapter 9)
1.
Why does Berkeley think absolute space is "mere nothing"?
2.
Why does Berkeley think it makes no sense to speak of the rotational motion of two globes in an otherwise empty universe?
3.
According to Berkeley, what causes the water to recede from the axis of rotation in Newton's spinning bucket?  Why is this an inadequate response?
4.
According to Berkeley, with respect to what is the water in Newton's spinning bucket rotating?
5.
According to Mach, why should mechanics be concerned only with relative motions and not absolute motions?
6.
According to Mach, what "twofold error" do we commit when we attempt to talk of the motion of a body K in the absence of other reference bodies?
7.
Why does Mach think it is "not permitted [of] us to say how things would be if the earth did not rotate"?
8.
What conclusion about the motion of the water in Newton's spinning bucket does Mach think it is legitimate to draw?  How is this conclusion different from the conclusion that Newton draws?
9.
Instead of Newton's absolute space, what does Mach suggest we use as a frame of reference from which to judge intertial motions?

Study questions on Kant - Part 1 (Huggett, Chapter 11)
Concerning the Ultimate Foundation of the Differentiation of Regions of Space
1.
According to Kant, what does a region of space consist of?
2.
According to Kant, how do we determine the position of places in nature?
3.
According to Kant, what does the "complete principle of determining a physical form" rest on?
4.
According to Kant, what distinguishes a right hand from a left hand?
5.
What is Kant's definition of an "incongruent counterpart"?  Give an example.
6.
Kant refers to an "inner principle" by which incongruent counterparts can be distinguished.  Why can't this inner principle be associated with the different ways in which the parts of an object are connected to each other?
7.
Suppose the only thing in the universe was a human hand.  Does Kant think it necessarily would have to be a right hand or a left hand?
8.
Suppose the only thing in the universe was a human right hand.  What does Kant think this would entail about the reality of space?
Commentary
9.
What does it mean to say that mirror images are incongruent?
10.
In 2-dimensional space, does the letter "F" have an incongruent counterpart?  Explain.
11.
Why does the definition of incongruent counterparts in 2-dimensional space need to be restricted to local regions of space?
12.
How are the concepts of "handedness" and "incongruence" related?
13.
How can a relationist respond to the charge that there are no relational differences between right and left hands?
14.
According to Kant, would reflecting the entire universe to produce a mirror image result in a different universe?  Would such a mirror image count as a different universe for a relationist?
15.
How can the "reflected universe" example be used as an argument against absolute space?

Study questions on Kant - Part 2 (Huggett, Chapter 12)
The Critique of Pure Reason
1.
Does Kant think all knowledge begins with experience?  Does he think all knowledge arises purely out of experience?
2.
What characteristics must knowledge have to be considered a priori for Kant?
3.
Give an example of a priori knowledge.
4.
What is an analytic judgement?  Give an example.
5.
What is a synthetic judgement?  Give an example.
6.
Are judgements of experience analytic or synthetic?
7.
What is the "pure form of sensibility"?  In what sense is it a priori?
8.
What is space, according to Kant?
9.
If knowledge of space were a posteriori (aquired through experience alone), what would this entail about truths like "there is only one straight line between any two points"?
10.
What does it mean to say that Euclidean geometry consists of synthetic a priori knowledge?
11.
What does Kant mean when he says, "It is therefore solely from the human standpoint that we can speak of space"?
Commentary
12.
What does the existence of consistent non-Euclidiean geometries entail about Kant's claim that Euclidean geometry consists of synthetic a priori truths?
13.
Is it a necessary and universal truth that through any point only one line can be drawn that is parallel to another line?
14.
How does elliptical geometry differ from Euclidean geometry?
15.
How does hyperbolic geometry differ from Euclidean geometry

Study questions on Poincare (Huggett, Chapter 13)
Space and Geometry
1.
Why does Poincare claim that, if there were no solid bodies in nature, there would be no geometry?
2.
According to Poincare, what does it mean to say that space is homogeneous and isotropic?
3.
What does Poincare mean when he says that geometry is only the summary of the laws by which images we experience succeed each other?  How is this different from Kant's conception of geometry?
4.
In what sense is Poincare's sphere world a non-Euclidean world?
5.
According to Poincare, what is the role of experiment in determining the geometric properties of physical space?
Experiment and Geometry
6.
According to Poincare, will astronomical observations of, say, the parallax of distant stars ever enable us to decide what the geometrical properties of space are?
7.
How can Poincare claim both that no experiment will ever be in contradiction with Euclidean geometry and that no experiment will ever be in contradiction with Lobatschewskian geometr
Commentary
8.
In discussing Poincare's heated disk, why should we replace his heat deformation force with a "universal" deformation force that affects all things in the same way?
9.
Why do the surveyors in the disk world believe their space is infinite?
10.
Why do the surveyors in the disk world believe the geometrical properties of their space are Lobatschewskian (hyperbolic)?
11.
How might other disk scientists argue against the conclusion of the surveyors in #10?
12.
According to Poincare, what factors influence any attempt at conducting surveying measurements?
13.
What does it mean to say that the choice of geometry is a convention?

Study questions on Einstein (Huggett, Chapter 14)
1.
What are two ways of regarding concepts, according to Einstein?
2.
What does the concept of space presuppose?
3.
According to Einstein, does Newtonian absolute space affect masses?  Do masses affect it?
4.
What role did the ether have for 19th century physicists?
5.
According to Einstein, what is the relationship between a physical field and physical space (i.e., the ether)?
6.
What is the significance of Lorentz transformations?
7.
What is the principle that characterizes the heuristic method of the special theory of relativity?
8.
What does the empirical equivalence of inert and gravitational masses entail?
9.
What must be done to the principle in #7 above in order to arrive at the general theory of relativity?
10.
How are Riemannian spaces different from Euclidean space?
11.
The metric field gmn determines the structure of a Riemannian space.  What did Einstein assume about the metric field?
12.
In what sense is space no longer absolute in general relativity?