Philosophy of Physics

J Butterfield : MR13, Mondays 4.30 – 6.00ish

The CMS Handbook Description
This is a graduate course, i.e. not examinable for Part III. It will meet once a week for two terms, analysing some philosophical aspects of classical and quantum physics. Since philosophy of physics is an inter-disciplinary subject (and the course is not examinable!), I propose:
(i): to back up the lectures by allowing extra time for discussion , i.e. up to 90 minutes each week;
(ii): to let the content and level be influenced by the interests of those attending.
But (notwithstanding (ii)!) the Michaelmas Term will be about symmetry principles, especially permutation, spacetime and gauge symmetries. In the Lent Term, I expect to discuss the emergence of the classical world from quantum theory, and the algebraic approach to quantum statistical mechanics.

Desirable Previous Knowledge
It will be desirable to know (i) basic classical mechanics, including Lagrangian and Hamiltonian methods; and (ii) basic quantum mechanics, including tensor products. But for the Michaelmas Term's topic of symmetry, the modern geometric formulation of classical mechanics, and the application of group theory to quantum theory, will not be assumed: what we need will be developed in the lectures. And similarly for the Lent Term's topics: the technicalities of the quantum measurement problem (such as improper mixtures), or of the algebraic approach to quantum theory, will not be assumed; what we need will be developed in the lectures.

Introductory Reading
Weyl, H. Symmetry. Princeton University Press.
Bell, J. Speakable and Unspeakable in Quantum Mechanics. CUP.

Reading to complement course material
Brading, K. and Castellani, E. (eds.) Symmetries in Physics. CUP.
Isham, C. Modern Differential Geometry for Physicists. World Scientific.
Landsman, N. Between classical and quantum. In Butterfield, J. and Earman, J. (eds.) Handbook of the Philosophy of Physics, 2 volumes, Elsevier. Available at: http://arxiv.org/abs/quant-ph/0506082, and at: http://philsci-archive.pitt.edu/archive/00002328/
Sewell, G. The Quantum Theory of Collective Phenomena. OUP.
Sternberg, S. Group Theory and Physics. CUP.

Schedule

Week 1, 12 October: Discussion of plan, and the Aharonov-Bohm Effect.
Gordon Belot, ‘Understanding Electromagnetism’, British Journal for Philosophy of Science 49, 1998, 531-555. Available at Google Scholar, ejournals at Cambridge etc

Week 2, 19 October: JNB away: Proposed talk
Adam Caulton: The analogy proposed by John Stachel between the identity of spacetime points and quantum particles.
Caulton and JNB: `Symmetries and Paraparticles as a Motivation for Structuralism’, MS

Weeks 3 onwards: Four possible stages---to be voted on!
For each stage, details (for vividness, but changeable!) are given below
(A): Identity from a philosophical perspective;
(B): Identity in physics;
(C): Symmetry especially in mechanics, classical and quantum; gauges
(D): Pedagogy about differential geometry.

(A) Identity in Philosophy; week 1: Identity and indiscernibility: traditional views
The Strong Principle of the Identity of Indiscernibles (PII), and haecceitism
General philosophical introduction (as a dialogue!):
1) Black, M. [1952]: The identity of indiscernibles, Mind 61, 153-164; and in K. Brading and E. Castellani ed Symmetries in Physics: philosophical reflections, Cambridge University Press.
Readings for the two doctrines:
2) Hacking, I [1975]: The identity of indiscernibles, Journal of Philosophy, 72, 249-256.
Haecceitism:
3) French, S. [1995]: `Hacking away at the identity of indiscernibles: possible worlds and Einstein's principle of equivalence', Journal of Philosophy, 92, 455-466.
4) Adams, R [1979]: `Primitive thisness and primitive identity’, Journal of Philosophy, 74, 5-26.

(A) Identity in Philosophy; week 2: Identity and indiscernibility: two new views
The weak PII, and Qualitative Identity with Indiscernibles.
1) Weak PII: Saunders, S [2003], `Physics and Leibniz's Principles', in K. Brading and E. Castellani, (eds.), Symmetries in Physics: Philosophical Reflections, Cambridge University Press. Available at: http://users.ox.ac.uk/~lina0174/research.html
2) Weak PII: K. Hawley, `Weak discernibility’, Analysis, 66 (2006), 300-303; and Identity and Indiscernibility, Mind 118 (2009), 101-119.
3) Qualitative Identity with Indiscernibles:
Ladyman, J. [2007]: `Scientific structuralism: on the identity and diversity of objects in a structure', Aristotelian Society Supplementary Volume, 81, pp. 23-44.

Summing up! 4) Caulton and Butterfield, On Kinds of Indiscernibility in Logic and Metaphysics, MS.

(B) Identity in Physics; week 1: (a) spacetime (b) the quantum
(a) spacetime
1) Saunders, S. [2003b]: `Indiscernibles, covariance and other symmetries: the case for non-reductive relationism', in A. Ashtkar, D. Howard, J. Renn, S. Sarkar and A. Shimony (eds.), Revisiting the Foundations of Relativistic Physics: Festschrift in Honour of John Stachel, Amsterdam: Kluwer.
Available at: http://users.ox.ac.uk/~lina0174/research.html
2) Pooley, O. [2006]: `Points, particles, and structural realism', in D. Rickles, S. French & J. Saatsi (eds.), The Structural Foundations of Quantum Gravity, Oxford: Oxford University Press, pp. 83--120.
3) Norton, J, `General covariance, gauge theories and Kretschmann objection’, in K. Brading and E. Castellani, (eds.), Symmetries in Physics: Philosophical Reflections, Cambridge University Press.
4) Esfeld, M and Lam, V [2008]: `Modest structural realism', Synthese, 160, pp. 27-46.

(b) the quantum: the orthodoxy that quantum theory shows PII is false
5) French, S. and Krause, D. [2006]: Identity in Physics. Oxford: Oxford University Press; Section 4.2 pp. 149-173. OR: French, S. and Redhead, M. [1988]: `Quantum physics and the identity of indiscernibles', British Journal for the Philosophy of Science, 39, pp. 233-46.
6) Butterfield, J. N. [1993]: `Interpretation and identity in quantum theory', Studies in the History and Philosophy of Science, 24, pp. 443-76.
7) Huggett, N: `Quarticles and the Identity of Indiscernibles’, in K. Brading and E. Castellani, (eds.), Symmetries in Physics: Philosophical Reflections, Cambridge University Press. An improved version is at:
http://philsci-archive.pitt.edu/archive/00001875/

(B) Identity in Physics; week 2: more quantum
(a): Restricting quantities vs restricting states: physical issues
1) French, S. and Krause, D. [2006]: Identity in Physics. Oxford: Oxford University Press. Section 4.1, pp. 138-148.
2) Messiah, A and Greenberg, O. `Symmetrization Postulate and its experimental foundation’, Physical Review 136, 1964, pp B248-267.
3) Redhead, M. and Teller, P. `Particle labels, and the theory of indistinguishable particles in quantum mechanics’, British Journal for the Philosophy of Science, 43, p. 201-218.

(b): Identity in quantum mechanics, concluded
4) Muller, F. A. and Saunders, S. [2008]: `Discerning fermions', British Journal for the Philosophy of Science, 59 (2008), 499-548.
5) Muller, F.A. and Seevinck, M.P. (2009) Discerning Elementary Particles, forthcoming in Philosophy of Science. At: http://philsci-archive.pitt.edu/archive/00004642/.
6) Saunders, S. [2006]: `Are quantum particles objects?', Analysis, 66, pp. 52-63.
7) Dieks D and Versteegh, M. `Identical quantum particles and weak discernibility’, available at: http://philsci-archive.pitt.edu/archive/00003598/ [October 2007 version]

Other topics one might consider:
On quantum statistics:
(a) Huggett, N. `On the Significance of Permutation Symmetry’, British Journal for the
Philosophy of Science, 50, 1999: 325-47.
(b) Saunders, S. [2006] On the Explanation for Quantum Statistics, Studies in the History and Philosophy of Modern Physics, 37, 192-211
On anyons:
(a) F. Wilczek, ‘Anyons’, Scientific American, May 1991, p. 24-31.
(b) I Aitchison and N. Mavromatos, ‘Anyons’, Contemporary Physics 32, 1991, 219-233.
(c) J. Leinaas, J. Myrheim, ‘The theory identical particles’, Nuovo Cimento 37B, 1977, p1
(C1) Symmetries, especially in mechanics
(a) general orientation
0) Belot [2003], `Notes on symmetries', in K. Brading and E. Castellani ed. Symmetries in Physics: philosophical reflections, Cambridge UP
1) Healey, R `Perfect Symmetries’, BJPS forthcoming,
http://philsci-archive.pitt.edu/archive/00004144/
2) P. Kosso, ‘Empirical status of symmetries in physics’, British Journal for the Philosophy of Science 51 2004, 81-98
3) Roberts, J `A Puzzle about laws, symmetries and measurability’, British Journal for the Philosophy of Science 59 2008, 143-168:
and: http://philsci-archive.pitt.edu/archive/00003920/

(b) Symmetry and conservation laws in elementary classical theories:.
1) JNB, ‘On Symmetries and Conserved Quantities in Classical Mechanics’, in W. Demopoulos and I. Pitowsky (eds.), Physical Theory and its Interpretation, Springer 2006; 43 - 99; Available at: http://philsci-archive.pitt.edu/archive/00002362/
2) G. Belot, `Principle of Sufficient Reason’, Journal of Philosophy 2001; and http://philsci-archive.pitt.edu/archive/00000448/
3) Lange, M, `Laws and meta-laws of nature’, Studies in the History and Philosophy of Modern Physics 38, 457-481.
4) S. Smith, `Symmetries and the explanation of conservation laws ..’ Studies in the History and Philosophy of Modern Physics 39, 325-345
An unusual perspective on the philosophy (and history) of classical mechanics:
O. Darrigol, `On the necessary truth of classical mechanics’, Studies in the History and Philosophy of Modern Physics 38, 2007, 757-800
Finally: Working towards the problem of time in general relativity!
Belot, G (2006) ‘The Representation of Time and Change in Mechanics’, in J. Butterfield and J. Earman (eds.), Handbook of the Philosophy of Physics, and
http://philsci-archive.pitt.edu/archive/00002549/

(C2) Gauges and All That
(a) General orientation
1) Main book; R. Healey, Gauging What’s Real, OUP
2) Guay’s review of Healey is at: http://philsci-archive.pitt.edu/archive/00004143/
3) Healey, Holism non-separability in physics, Stanford Encyclopedia http://www.seop.leeds.ac.uk/entries/physics-holism/
4) T. Maudlin, Chapter 3 of The Metaphysics in Physics OUP
5) Papers by Belot, Martin, Redhead, Earman, Wallace in K. Brading and E. Castellani ed. Symmetries in Physics: philosophical reflections
6) H Brown, K Brading ‘Are gauge symmetry transformations observable?’, British Journal for the Philosophy of Science 55 2004, 645-665; and at
http://philsci-archive.pitt.edu/archive/00001436/

(b) The AB effect; the debate between Healey, Maudlin, and Leeds
1) Belot, ‘Understanding Electromagnetism’, British Journal for Philosophy of Science 49, 1998, 531-555
2) Healey, `Non-locality and the AB effect’, Philosophy of Science 64 1997, 18-41
3) Maudlin, ‘Healey on the AB effect’, Philosophy of Science 65 1998, 361-368
4) Leeds, `Gauges: A,B, Yang, Healey’, Philosophy of Science 66 1999, 606-627
5) Lyre, `Holism and structuralism in U(1) gauge theory’, Studies in History and Philosophy of Modern Physics 35 (2004) 643-670.
6) Myrvold, `Nonseparability, Classical and Quantum’, MS.

(c) More advanced discussion, including eg some quantization theory
1) Belot, G., `Symmetry and gauge freedom’, Studies in History and Philosophy of Modern Physics 34 (2003) 189–225. and http://philsci-archive.pitt.edu/archive/00001513/
2) Guay, A. `A partial elucidation of the gauge principle’, Studies in History and Philosophy of Modern Physics 39, (2008), 346-363.
2) Catren `Geometrical foundations of classical YM theories’, Studies in History and Philosophy of Modern Physics forthcoming.

(D) Differential Geometry
I would recommend as background that is useful e.g. for Belot, G., `Symmetry and gauge freedom’, just above:
Isham, C. Modern Differential Geometry for Physicists. World Scientific.