How can the universe meaningfully have an alternating direction of time? [pp. ... If you are assigned to write an essay
Reichenbach’s The Direction of Time HPS Part II Primary Source Seminar Michaelmas 2017 Matt Farr |
[email protected]
Overview. In his final work, Hans Reichenbach applied his brand of logical empiricism to the philosophical problem of time's arrow. The Direction of Time (1956) set out novel and highly influential theories of both time and causation. Starting with a rigorous assessment of the emotive significance of time, Reichenbach explores the nature of causality in classical physics, the thermodynamic basis for the concepts of earlier and later, and the difference between cause and effect, as determined by his principle of common cause. We will consider the philosophical and scientific motivations for his views, and the influence they have had on contemporary theories of time and causation.
Schedule of seminars. The following is a summary of each seminar. I have included main reading (Reichenbach), and supplementary background reading. For each seminar, there are a list of questions to consider that will form the backbone for the seminar discussion. These are designed to focus your reading of the primary source. Presenters are welcome to cover any of the questions relating to the week of their presentation.
1. The Problems of Time • October 9th We cover the introductory chapter and the general aims of the book. Reichenbach took himself to be addressing the philosophical problems of time by (1) taking a broadly logical empiricist approach to metaphysics, and (2) grounding the various common-sense properties of time in physical theory. Main reading: Preface and Ch1 of DOT. Supplementary reading: Mehlberg, H. (1961) Review of Reichenbach’s ‘The Direction of Time’, The Philosophical Review, Vol. 71, No. 1, pp. 99-104 Ch 3 & 4 of Eddington, A. (1928) The Nature of the Physical World. Cambridge University Press. Price, H. (2011). The Flow of Time. In Callender (ed) Oxford Handbook of Philosophy of Time, Oxford University Press.
2. Time in Classical Mechanics • October 16th Time in classical mechanics has the surprising property of being reversible: if a process can happen forward in time, it can also happen backwards in time. We look at Reichenbach’s ideas of causal order and causal direction in this framework, his theory of ‘equivalent descriptions’, and how his work relates to contemporary worries about the relationship between causation and time symmetry. Main reading: Ch2 of DOT. Supplementary reading: On Reichenbach’s causal theory of time: Ch6 of Van Fraassen, B. C. (1970) An Introduction to the Philosophy of Time and Space, Random House. Reichenbach’s The Direction of Time
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Ch7 of Grünbaum, A. (1964) Philosophical Problems of Space and Time, Routledge. On classical time symmetry Ch1 of Albert, D.Z. (2000) Time and Chance, Harvard University Press. Farr, M. (forthcoming) Causation and Time Reversal, British Journal of Philosophy of Science. On equivalent descriptions: Ch8 of Reichenbach, H. (1973). The Rise of Scientific Philosophy. University of California Press. Questions for discussion: 1. What is the ‘Causal Theory of Time’? [pp. 24-27] 2. In what sense do positive time and negative time ‘supply equivalent descriptions’ (p. 31)? [pp. 30-36] 3. What does it mean for time in classical mechanics to be ‘ordered but not directed’? [pp. 26-42] 4. What does Reichenbach mean by when he says “the sign of velocity remains unknown as long as no irreversible processes are adduced for the interpretation of the observations” (p. 36)? [pp. 32-36] 5. Do interventions change only the future and not the past? [pp. 45-47] (Bonus: can tennis players run backwards? [p. 47])
3. The Arrow of Time • October 23rd Unlike the time symmetry of classical mechanics, the world of our experience is directed in time. This is often traced back to the time asymmetry of thermodynamic processes. We look at the problem of time’s arrow, the role it played in the foundations of statistical mechanics, and Reichenbach’s reductionist account of time direction in terms of the thermodynamical arrow. This chapter (ch. 3 [§§7–16]) is a monster, and our focus will be on Reichenbach’s reductionist account of the direction, the key parts of which are sections 13, 15 and 16, with sections 7 and 8 useful background. Main reading: Ch3 of DOT. [Long and very dense chapter. Main focus on §§7–8 and §§13, 15–16] Supplementary reading: On thermodynamic arrow of time: Ch 2 of Price, H. (1996), Time’s Arrow and Archimedes’ Point, Oxford University Press. On reductionism vs non-reductionism about arrow of time: Earman, J. (1974). An Attempt to Add a Little Direction to" The Problem of the Direction of Time". Philosophy of Science, 41(1), 15-47. [especially sec 3] Ch 5 of Maudlin (2007), The Metaphysics Within Physics, Oxford University Press. Savitt, S. (1996) The Direction of Time, British Journal of Philosophy of Science, 47 (3): 347-370 [particularly sections 1-4] Price, H. (2002). Boltzmann's time bomb. The British journal for the philosophy of science, 53(1), 83-119. Sec. 3 of Price, H. (2011). The Flow of Time. In Callender (ed) Oxford Handbook of Philosophy of Time, Oxford University Press. Questions for discussion: 6. What does Reichenbach mean when defining ‘the direction of positive time’ as ‘the direction in which most thermodynamical processes in isolated systems occur’ (p. 127)? [sec. 15] 7. What is the problem posed by the ‘Reversibility Objection’? [sec. 13] 8. What are the differences between ‘reductionist’ and ‘non-reductionist’ accounts of time direction? [sec. 15 and supplementary readings, esp. sec 3 of Earman and sec 3 of Price] 9. How can the universe meaningfully have an alternating direction of time? [pp. 127-129] 10. Does the universe as a whole have a direction of time? [bottom of p. 128 to p. 129; also see sec. 3.5 of Price (2011)] Reichenbach’s The Direction of Time
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4. The Direction of Causation • October 30th The most written-about component of The Direction of Time is Reichenbach’s ‘principle of common cause’, which he uses to act as a definition of the direction of time. Despite its intuitive appeal, many have held the principle to fail, especially with respect to quantum mechanics. We will look at what the core of this principle is and how it fares in the contemporary literature on causation. Main reading: Ch4 of DOT. Supplementary reading: On the Principle of Common Cause: Arntzenius, F, (2010) "Reichenbach's Common Cause Principle", The Stanford Encyclopedia of Philosophy (Fall 2010 Edition), Edward N. Zalta (ed.), URL = . Sober, E., (1988) The Principle of the Common Cause, in Probability and Causality, J. Fetzer (ed.). Dordrecht: Reidel, pp. 211–229. On the Principle of Common Cause and the arrow of time: Ch8 of Dowe, P. (2000). Physical Causation, Cambridge: Cambridge University Press. Price, H. (1996). Backward causation and the direction of causal processes: reply to Dowe. Mind, 105(419), 467-474. On the Mark Principle and causal processes: Ch4 of Dowe, P. 2000. Physical Causation, Cambridge: Cambridge University Press. Questions for discussion: 11. What is the difference between ‘producing’ and ‘recording’? [pp. 149-156] 12. Are there ‘causes’ and ‘effects’ in time reversible (i.e. microscopic) systems? [pp. 149-156] 13. What is the principle of common cause? [pp. 157-166] 14. What is the relationship between the principle of common cause and the direction of time? [pp. 157-186] 15. What is the significance of the Mark Principle for the directionality of causation? [pp. 197-206]
Practical Information. The course consists of four weekly seminars, run by Matt Farr, on Mondays 11-12, weeks 1-4 of Michaelmas, in Seminar Room 2. The seminars will be made up of short lectures, student presentations, and group discussion. Students are required to attend four series of primary source seminars, and write two 3000-word essays, each on a different primary source. Students are to send the Department office a list of four primary sources on which they would like to write, in order of preference, by October 24th. If you are assigned to write an essay on Reichenbach’s The Direction of Time, please email me to arrange a meeting to discuss supervisions. The deadline for essay submissions is January 29th, 2018. Primary source essays are expected to closely engage with the relevant primary texts. The departmental guidelines state that this engagement may include any the following: “historical contexualisation of the source; a comparative study of the source; questions concerning the reception of the source; an approach addressing a single passage from a source in great depth; the literary and rhetorical analysis of a source; and a close philosophical analysis of the argument in the source”. For full information about Primary Source Seminars, please read the departmental guidelines: https://www.hps.cam.ac.uk/students/partii-guide/primary-sources
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