Philosophy of Time Travel (PHIL10125) Course Guide 2020/21

Total Page:16

File Type:pdf, Size:1020Kb

Philosophy of Time Travel (PHIL10125) Course Guide 2020/21 Philosophy of Time Travel (PHIL10125) Course Guide 2020/21 Course Organiser: Dr. Alasdair Richmond, [email protected] Dugald Stewart Building, room 6.11, 0131 650 3656 I hope to be offering office hours as well but they will obviously be contingent on how the re-opening of University proceeds in the wake of Covid-19. So look out for further announcements but chats via (e.g.) Skye or Teams will be possible regardless. Course Secretary: Ms. Ann Marie Cowe, [email protected] Undergraduate Teaching Office, Dugald Stewart Building, room G.06, 0131 650 3961 Department of Philosophy School of Philosophy, Psychology and Language Sciences University of Edinburgh Course Aims and Objectives This course will offer detailed seminars on key philosophical issues in the philosophy of time travel, largely with an analytical slant. Students should end this course conversant with a range of significant metaphysical (and other) issues surrounding time travel. No detailed logical, scientific or metaphysical expertise will be assumed, and the course is intended to be accessible to students with a wide range of philosophical interests and aptitudes. Intended Learning Outcomes To develop further the philosophical skills, and to extend and deepen the philosophical knowledge, acquired in previous philosophy courses. Transferable skills that students will acquire or hone in taking this course should include the following: written skills (through summative essays) oral communication skills (through lecturer-led and/or student-led seminar discussions) presentation skills (through giving and criticising student presentations) analytical skills (through exploring a carefully-chosen series of philosophical texts) ability to recognise and critically assess an argument. Lecture Times and Locations Second semester Day/ Time: Again, this is all rather contingent on how re-opening proceeds. However please note that: I) all lecture content is already available in pre-recorded form on the LEARN page for this course, and ii) we have resources to allow this course to proceed fully online if required. I hope to have (at the very least) small group face-to-face meetings but rest assured, the course can carry on as planned even if direct meetings prove impracticable. (I have delivered entire courses electronically before, I stress.) Lecture Content and Readings Asterisked items below are available from JSTOR. All other journal items should be available via the electronic journals access facilitated by the Library / MyEd. Any problems, do please let me know. Main texts: *** Please note: electronic alternatives to print resources can always be provided if (e.g.) the Main Library proves difficult of access. There is no irreplaceable reading that is only available in print. As always, please ask if I can help at all. *** This is a research-led course, driven by my ongoing monograph and spin-off articles on sundry aspects of time travel. Just recently (2018 and 2020 respectively), the Oxford University Press have published Ryan Wasserman’s Paradoxes of Time Travel and Nikk Effingham’s Time Travel: Probability and Impossibility, the first full-length books on the philosophy of time travel. Both books can be recommended in their entirety and should be available (again in their entirety) electronically via the Main Library. (My review of Wasserman appeared in Analysis in 2018. By the time the course is actually delivered, my review of Effingham should also be available, again from Analysis.) This next is still probably the best available introduction to space and time in general: Barry Dainton, Time and Space, Chesham, Acumen, 2001, second edition Durham Acumen 2010, multiple copies should be available in the Library Hub Reserve (at shelf-mark BD632 Dai). I spent academic years 2008-2009 and 2016-17 on research-leave, working on a raft of time-travel related articles plus a book. On request, I am happy to circulate draft papers and other works-in-progress of my own. (Just please don’t post my draft stuff anywhere – I’ll just end up looking silly / even sillier. Quite where my book is after Wasserman and Effingham is another story …) Please note that the following lists of readings are prioritised, with the most important / useful readings at the top. So the recommended way to tackle the suggested readings is to start at the top of each list and work downwards. If you read only one thing for each seminar, read the top one. Week 1 Introducing the Debate – What is Time Travel? The Lewisian Analysis. Recommended reading: David Lewis, ‘The Paradoxes of Time Travel’, The American Philosophical Quarterly, 13, 1976: 145-52. Much reprinted in (for examples) The Philosophy of Time, (edd. Robin Le Poidevin and Murray MacBeath), (Oxford, Oxford University Press, 1993): 134-46 and in Metaphysics: The Big Questions, ed. D. Zimmerman and P. van Inwagen, (Oxford, Blackwell, 1998): 159-169. Online at: http://www.csus.edu/indiv/m/merlinos/Paradoxes%20of%20Time%20Travel.pdf AR, ‘Recent Work: Time Travel’, Philosophical Books, 44, 2003: 297-309. DOI: http://dx.doi.org/10.1111/1468-0149.00308 Useful background / of related interest: Barry Dainton, Time and Space, EITHER 2001 edition, Chapter 8, 110-113, 116- 119; OR 2010 edition, 121-124; 127-130. Paul Horwich, ‘On Some Alleged Paradoxes of Time Travel’, The Journal of Philosophy, LXXII, 1975: 432-444. Week 2 Developments of, and Objections to, the Lewisian Analysis. Recommended reading: Phil Dowe, ‘The Case for Time Travel’, Philosophy, 75, 2000, 441-451. William Grey, ‘Troubles With Time Travel’, Philosophy, 74, 1999: 55-70. Useful background / of related interest: Jonathan Harrison, ‘Dr. Who and the Philosophers or Time-Travel for Beginners’, Proceedings of the Aristotelian Society, Supplementary Volume, 1971: 1-24. Jonathan Harrison, ‘Analysis Problem No. 18’, Analysis, 39, 1979: 65-66. Jonathan Harrison, ‘Report on Analysis Problem No. 18’, Analysis, 40: 65-9. Week 3 A) Introducing Relativity. Barry Dainton, Time and Space, EITHER 2001 edition, Chapters 16 and 18, 254- 68, 284-300; OR 2010 edition, Chapters 18 and 20, 313-327; 343-367. Craig Bourne, A Future for Presentism, Oxford, Oxford University Press, 2006, Ch. 5: 141–159. (Whole book available electronically via the Main Library.) Robert Weingard, ‘General Relativity and the Conceivability of Time Travel’, Philosophy of Science, 46, 1979: 328-32. Further reading: John Earman 1972: ‘Implications of Causal Propagation Outside the Null Cone’, Australasian Journal of Philosophy, 50, 1972: 222-237. Hajnal Andréka, Judit X. Madarász, István Németi and A. Andai, ‘Visualizing Some Ideas About Gödel-type Rotating Universes’, (2002), draft available at: www.math-inst.hu/pub/algebraic-logic/goduniv/goduniv11.ps.gz Sean Carroll, ‘Lecture Notes on General Relativity’, 1997, archived at: http://arxiv.org/abs/gr-qc/9712019 B) Gödel and the Unreality of Time Recommended reading: Barry Dainton, Time and Space, EITHER 2001 edition, Chapter 19, 314-19; OR 2010 edition, 381-386. Craig Bourne, A Future for Presentism, Oxford, Oxford University Press, 2006, Ch. 8: 204–224. (Whole book available electronically via the Main Library.) Steven S. Savitt, ‘The Replacement of Time’, Australasian Journal of Philosophy, 72, 1994: 463-74. Useful background / of related interest: Palle Yourgrau, The Disappearance of Time: Kurt Gödel and the Idealistic Tradition in Philosophy, Cambridge, Cambridge University Press, 1991. Palle Yourgrau, Gödel Meets Einstein: Time Travel in the Gödel Universe, La Salle / Chicago, Open Court, 1999. Palle Yourgrau, A World Without Time: The Forgotten Legacy of Gödel and Einstein, New York, Basic Books, 2005. Week 4 The Cheshire Cat Problem and Other Spatial Perplexities. Recommended reading: Robin Le Poidevin, ‘The Cheshire Cat Problem and Other Spatial Obstacles to Backwards Time Travel’, The Monist, 88, 2005: 336-352. Access via ‘Philosophy Online’: http://www.pdcnet.org/collection/show?id=monist_2005_0088_0003_0336_0352& file_type=pdf&page=1 AR, ‘Time Travel, Hyperspace and Cheshire Cats’, Synthese 2017, online: https://link.springer.com/article/10.1007%2Fs11229-017-1448-2 Sara Bernstein, ‘Nowhere Man: Time Travel and Spatial Location’, Midwest Studies in Philosophy, 39, 2015: 158-168 Useful background / of related interest: Robin Le Poidevin, ‘The Chemistry of Space’, Australasian Journal of Philosophy, 72, 1994: 77-88. G. J. Whitrow, ‘Why Physical Space Has Three Dimensions’, The British Journal for the Philosophy of Science, 6, (1955), 13-31. Cody S. Gilmore, ‘Time Travel, Coinciding Objects and Persistence’, Oxford Studies in Metaphysics, III, 2007 pre-print on-line at: http://www.unomaha.edu/philosophy/TTCOandPmay05.pdf Week 5 Causal Loops Revisited (Part One): ‘Jane’, Jocasta, Dee and Dum. Information Loops and Object Loops. Recommended reading: Richard Hanley, ‘No End in Sight: Causal Loops in Philosophy, Physics and Fiction’, Synthese, 141, 2004: 123-52. Jonathan Harrison, ‘Analysis Problem No. 18’, Analysis, 39, 1979: 65-66. Useful background / of related interest: Jonathan Harrison, ‘Report on Analysis Problem No. 18’, Analysis, 40: 65-9. Margarita R. Levin, ‘Swords’ Points’, Analysis, 40, 1980: 69-70. Phil Dowe and Dylan Evans, ‘How to ‘Clone’ Sexually’, 1998, MS available online at: http://www.uq.edu.au/~uqpdowe/Research/pdfs/cloning.pdf Week 6 A) Causal Loops Revisited (Part Two): Mellor and the Facts of Causation. Recommended reading: D. H. Mellor, Real Time II, (London, Routledge, 1998), 125-135. Susan S. Weir, ‘Closed Time
Recommended publications
  • Arxiv:1911.08602V1 [Gr-Qc] 19 Nov 2019
    Causality violation without time-travel: closed lightlike paths in G¨odel'suniverse Brien C. Nolan Centre for Astrophysics and Relativity, School of Mathematical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland.∗ We revisit the issue of causality violations in G¨odel'suniverse, restricting to geodesic motions. It is well-known that while there are closed timelike curves in this spacetime, there are no closed causal geodesics. We show further that no observer can communicate directly (i.e. using a single causal geodesic) with their own past. However, we show that this type of causality violation can be achieved by a system of relays: we prove that from any event P in G¨odel'suniverse, there is a future-directed lightlike path - a sequence of future-directed null geodesic segments, laid end to end - which has P as its past and future endpoints. By analysing the envelope of the family of future directed null geodesics emanating from a point of the spacetime, we show that this lightlike path must contain a minimum of eight geodesic segments, and show further that this bound is attained. We prove a related general result, that events of a time orientable spacetime are connected by a (closed) timelike curve if and only if they are connected by a (closed) lightlike path. This suggests a means of violating causality in G¨odel'suniverse without the need for unfeasibly large accelerations, using instead a sequence of light signals reflected by a suitably located system of mirrors. I. INTRODUCTION: GODEL'S¨ UNIVERSE In 1949, Kurt G¨odel[1]published a solution of Einstein's equations which provides what appears to be the first example of a spacetime containing closed timelike curves (CTCs).
    [Show full text]
  • |||GET||| a Book That Was Lost Thirty-Five Stories 1St Edition
    A BOOK THAT WAS LOST THIRTY-FIVE STORIES 1ST EDITION DOWNLOAD FREE Alan Mintz | 9781592642540 | | | | | The First Forty Nine Stories Hemingway Ernest 9780353247529 Adler Transcript of the original source. Nevertheless, the editors steadfastly maintain that average readers are capable of understanding far more than the critics deem possible. See also: Outline of science fiction. Wright, who drove a cab. Retrieved 27 February There was also a tanning bed used in an episode, a product that wasn't introduced to North America until Hollywood, here I come! Understanding Kurt Vonnegut. Conventions in fandom, often shortened as "cons," such as " comic-con " are held in cities around the worldcatering to a local, regional, national, or international membership. Neo-Fan's Guidebook. They also tend to support the space program and the idea of contacting extraterrestrial civilizations. Chicago Sun-Times. Retrieved 10 April Further information: Skiffy. Mary Shelley wrote a number of science fiction novels including Frankenstein; or, The Modern Prometheusand is considered a major writer of the Romantic Age. Science fiction at Wikipedia's sister projects. Escapist Magazine. I feel that with being a parent. Atlas Obscura. You want to see some jazz? The character, a peripheral one at first, became central. Views Read Edit View history. Feldman urged him to stay. Joining the Marines gave Driver a sense A Book That Was Lost Thirty-Five Stories 1st edition purpose and some distance from his conservative religious upbringing. Faster-than-light communication Wormholes. Respected authors of mainstream literature have written science fiction. Retrieved 4 March Wolfe, Gary K. Science fiction portal. This was almost certainly a cost-saving measure.
    [Show full text]
  • The Theory of (Exclusively) Local Beables
    The Theory of (Exclusively) Local Beables Travis Norsen Marlboro College Marlboro, VT 05344 (Dated: June 17, 2010) Abstract It is shown how, starting with the de Broglie - Bohm pilot-wave theory, one can construct a new theory of the sort envisioned by several of QM’s founders: a Theory of Exclusively Local Beables (TELB). In particular, the usual quantum mechanical wave function (a function on a high-dimensional configuration space) is not among the beables posited by the new theory. Instead, each particle has an associated “pilot- wave” field (living in physical space). A number of additional fields (also fields on physical space) maintain what is described, in ordinary quantum theory, as “entanglement.” The theory allows some interesting new perspective on the kind of causation involved in pilot-wave theories in general. And it provides also a concrete example of an empirically viable quantum theory in whose formulation the wave function (on configuration space) does not appear – i.e., it is a theory according to which nothing corresponding to the configuration space wave function need actually exist. That is the theory’s raison d’etre and perhaps its only virtue. Its vices include the fact that it only reproduces the empirical predictions of the ordinary pilot-wave theory (equivalent, of course, to the predictions of ordinary quantum theory) for spinless non-relativistic particles, and only then for wave functions that are everywhere analytic. The goal is thus not to recommend the TELB proposed here as a replacement for ordinary pilot-wave theory (or ordinary quantum theory), but is rather to illustrate (with a crude first stab) that it might be possible to construct a plausible, empirically arXiv:0909.4553v3 [quant-ph] 17 Jun 2010 viable TELB, and to recommend this as an interesting and perhaps-fruitful program for future research.
    [Show full text]
  • 5 VII July 2017
    5 VII July 2017 International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor:6.887 Volume 5 Issue VII, July 2017- Available at www.ijraset.com An Introduction to Time Travel Rudradeep Goutam Mechanical Engg. Sawai Madhopur College of Engineering & Technology, Sawai Madhopur ,.Rajasthan Abstract: Time Travel is an interesting topic for a Human Being and also for physics in Ancient time, The Scientists Thought that the time travel is not possible but after the theory of relativity given by the Albert Einstein, changes the opinion towards the time travel. After this wonderful Research the Scientists started to work on making a Time Machine for Time Travel. Stephon Hawkins, Albert Einstein, Frank j. Tipler, Kurt godel are some well-known names who worked on the time machine. This Research paper introduce about the different ways of Time Travel and about problems to make them practically possible. Keywords: Time travel, Time machine, Holes, Relativity, Space, light, Universe I. INTRODUCTION After the discovery of three dimensions it was a challenge for physics to search fourth dimension. Quantum physics assumes The Time as a fourth special dimension with the three dimensions. Simply, Time is irreversible Succession of past to Future through the present. Science assumes that the time is unidirectional which is directed past to future but the question arise that: Is it possible to travel in Fourth dimension (Time) like the other three dimensions? The meaning of time Travel is to travel in past or future from present. The present is nothing but it is the link between past and future.
    [Show full text]
  • Cvi, 1999: 5-24
    Nicholas Huggett OFFICE: HOME: Department of Philosophy, M/C 267, 3730 N. Lake Shore Drive, #3B University of Illinois at Chicago, Chicago, IL 60613 601 South Morgan St, Chicago, IL 60607-7114 Telephone: 312-996-3022 773-818-5495/773-281-5728 Fax: 312-413-2093 Email: [email protected] EMPLOYMENT: 2015- : LAS Distinguished Professor, University of Illinois at Chicago. Spring 2018: Visiting Associate Dean, College of Liberal Arts and Sciences, University of Illinois at Chicago. 2009-15: Full Professor, University of Illinois at Chicago. 2001-9: Associate Professor, University of Illinois at Chicago. 1996-2001: Assistant Professor, University of Illinois at Chicago. 1995-6: Visiting Assistant Professor, Brown University. 1994-5: Visiting Assistant Professor, University of Kentucky. EDUCATION: Rutgers University: PhD, 1995. (Dissertation: The Philosophy of Fields and Particles in Classical and Quantum Mechanics, including The Problem of Renormalization. Supervised by Robert Weingard.) Oxford University: BA Hons in Physics and Philosophy, 1988. AWARDS AND FELLOWSHIPS: Foundational Questions Institute Member, 2017-. Outstanding Graduate Mentor Award, Graduate College, University of Illinois at Chicago, 2015. Professorial Fellow, Institute of Philosophy, School of Advanced Studies, University of London, April-May 2011. American Council of Learned Societies Collaborative Fellowship, 2010-13. Grant for full-time research. University of Illinois at Chicago Humanities Institute Fellow, 2005-6. Grant for full-time research. University of Illinois at Chicago, University Scholar, 2002-5. National Science Foundation Science and Technology Studies Scholars Award, 2001-2002. Grant for full-time research. !1/!13 Nicholas Huggett University of Illinois at Chicago Humanities Institute Fellow, 1999 -2000. Grant for full-time research.
    [Show full text]
  • You Zombies, Click and a Novel, 1632, Both of Which Are Available Online from Links in the Handout
    Instructor's notes to F402 Time Travel in Science Fiction Session 1 – Introduction Welcome to F402, Time Travel in Science Fiction. The objective of this course is to help you to read, understand and enjoy stories in the genre. The course is in two parts; the first is Today's lecture and discussion on the genre while the second is class discussions of two stories of opposite types. click The reading assignment consists of a short story, All You Zombies, click and a novel, 1632, both of which are available online from links in the handout. click For the convenience of those who prefer dead trees, I have listed a number of anthologies1 containing All You Zombies. Reading Assignment for Sessions 2-3 click All You Zombies is one of two tour de force stories by Robert A. Heinlein that left their mark on the genre for decades. Please read All You Zombies prior to the next session click and 1632 click click Part One, chapters 1-14 prior to the third session. Esc Session 1 Keep in mind that science fiction is a branch of literature, so the normal criteria of, e.g., characterization, consistency, continuity, plot structure, style, apply; I welcome comments, especially from those who have expertise in those areas. In addition, while a science fiction author must rely on the willing suspension of disbelief, he should do so sparingly. There is a lapse of continuity in 1632 between chapters 8 and 9; see whether you can spot it. I will suggest specific discussion points to start each discussion, but please bring up any other issues that you believe to be important or interesting.
    [Show full text]
  • Closed Timelike Curves, Singularities and Causality: a Survey from Gödel to Chronological Protection
    Closed Timelike Curves, Singularities and Causality: A Survey from Gödel to Chronological Protection Jean-Pierre Luminet Aix-Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille , France; Centre de Physique Théorique de Marseille (France) Observatoire de Paris, LUTH (France) [email protected] Abstract: I give a historical survey of the discussions about the existence of closed timelike curves in general relativistic models of the universe, opening the physical possibility of time travel in the past, as first recognized by K. Gödel in his rotating universe model of 1949. I emphasize that journeying into the past is intimately linked to spacetime models devoid of timelike singularities. Since such singularities arise as an inevitable consequence of the equations of general relativity given physically reasonable assumptions, time travel in the past becomes possible only when one or another of these assumptions is violated. It is the case with wormhole-type solutions. S. Hawking and other authors have tried to save the paradoxical consequences of time travel in the past by advocating physical mechanisms of chronological protection; however, such mechanisms remain presently unknown, even when quantum fluctuations near horizons are taken into account. I close the survey by a brief and pedestrian discussion of Causal Dynamical Triangulations, an approach to quantum gravity in which causality plays a seminal role. Keywords: time travel; closed timelike curves; singularities; wormholes; Gödel’s universe; chronological protection; causal dynamical triangulations 1. Introduction In 1949, the mathematician and logician Kurt Gödel, who had previously demonstrated the incompleteness theorems that broke ground in logic, mathematics, and philosophy, became interested in the theory of general relativity of Albert Einstein, of which he became a close colleague at the Institute for Advanced Study at Princeton.
    [Show full text]
  • The Philosophy and Physics of Time Travel: the Possibility of Time Travel
    University of Minnesota Morris Digital Well University of Minnesota Morris Digital Well Honors Capstone Projects Student Scholarship 2017 The Philosophy and Physics of Time Travel: The Possibility of Time Travel Ramitha Rupasinghe University of Minnesota, Morris, [email protected] Follow this and additional works at: https://digitalcommons.morris.umn.edu/honors Part of the Philosophy Commons, and the Physics Commons Recommended Citation Rupasinghe, Ramitha, "The Philosophy and Physics of Time Travel: The Possibility of Time Travel" (2017). Honors Capstone Projects. 1. https://digitalcommons.morris.umn.edu/honors/1 This Paper is brought to you for free and open access by the Student Scholarship at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Honors Capstone Projects by an authorized administrator of University of Minnesota Morris Digital Well. For more information, please contact [email protected]. The Philosophy and Physics of Time Travel: The possibility of time travel Ramitha Rupasinghe IS 4994H - Honors Capstone Project Defense Panel – Pieranna Garavaso, Michael Korth, James Togeas University of Minnesota, Morris Spring 2017 1. Introduction Time is mysterious. Philosophers and scientists have pondered the question of what time might be for centuries and yet till this day, we don’t know what it is. Everyone talks about time, in fact, it’s the most common noun per the Oxford Dictionary. It’s in everything from history to music to culture. Despite time’s mysterious nature there are a lot of things that we can discuss in a logical manner. Time travel on the other hand is even more mysterious.
    [Show full text]
  • Arxiv:Gr-Qc/0106048 14 Jun 2001
    Self-existing objects and auto-generated information in chronology-violating space-times: A philosophical discussion Gustavo E. Romero∗and Diego F. Torresy June 14, 2001 Instituto Argentino de Radioastronom´ıa, C.C.5, (1894) Villa Elisa, Buenos Aires, Argentina Abstract Closed time-like curves naturally appear in a variety of chronology-violating space-times. In these space-times, the Principle of Self-Consistency demands an harmony between local and global affairs that excludes grandfather-like paradoxes. However, self-existing objects trapped in CTCs are not seemingly avoided by the standard interpretation of this principle, usually constrained to a dynamical framework. In this paper we discuss whether we are committed to accept an ontology with self-existing objects if CTCs actually occur in the universe. In addition, the epistemological status of the Principle of Self- Consistency is analyzed and a discussion on the information flux through CTCs is presented. 1 Introduction One of the most fascinating aspects of the general theory of relativity (GTR) is that its field equations have solutions where the formation of closed time-like curves (CTCs) is possible. These curves represent the world lines of any physical system in a temporally orientable space-time that, moving always in the future direction, ends arriving back at some point of its own past. Although solutions of the Einstein field equations (EFEs) where CTCs exist are known at least since G¨odel's (1949) original work, it has been just in the last dozen of years that physicists have shown a strong and sustained interest on this topic. The renewed attraction of CTCs and their physical implications stem from the discovery, at the end of the 1980's, of traversable wormhole space-times (Morris et al.
    [Show full text]
  • Tinkering with Time the NEW TIME TRAVELERS: a JOURNEY to the on Our FRONTIERS of PHYSICS by DAVID TOOMEY Bookshelf W
    BOOKS & ARTS Tinkering with time THE NEW TIME TRAVELERS: A JOURNEY TO THE On our FRONTIERS OF PHYSICS BY DAVID TOOMEY bookshelf W. W. Norton & Co.: 2007. 320 pp. $25.95 Years ago, David Toomey picked up H. G. Wells’ moving clocks tick slowly, making time travel The Time Machine and couldn’t put it down. to the future possible. We now know a number The Mathematics of He was most interested in the drawing-room of solutions to Einstein’s equations of general Egypt, Mesopotamia, discussion between the time traveller and his relativity (1915) that are sufficiently twisted to China, India, and Islam: friends in which time as a fourth dimension was allow time travel to the past: Kurt Gödel’s 1949 A Sourcebook discussed, but wanted to know more about just rotating universe; the Morris–Thorne–Yurtsever edited by Victor J. Katz how that time machine might work. Toomey was wormhole (1988); the Tipler–van Stockum infinite therefore delighted to learn that that drawing- rotating cylinder, moving cosmic strings (myself), Princeton Univ. Press: room conversation continues today — this time the rotating black-hole interior (Brandon Carter), 2007. 685 pp. $75 among physicists. a Roman ring of wormholes (Matt Visser), the We’re aware that Toomey captures well the personalities Everett–Alcubierre warp drive, my and Li–Xin Li’s the ancient cultures of the ‘new time travelers’ — those physicists self-creating universe; Amos Ori’s torus; and were mathematically interested in whether time travel to the past is others. The book discusses all of these. advanced. Now possible — from Stephen Hawking’s sense of But can a time machine really be constructed? translations of early texts humour to Kip Thorne’s penchant for placing Hawking, like one of the time traveller’s sceptical from five key regions are scientific bets.
    [Show full text]
  • Minkowski Space-Time and Einstein's Now Conundrum
    NeuroQuantology | May 2018 | Volume 16 | Issue 5 | Page 23-30 | doi: 10.14704/nq.2018.16.5.1345 Sorli A., Minkowski Space-time and Einstein’s Now Conundrum Minkowski Space-time and Einstein’s Now Conundrum Amrit Sorli 1*, Steve Kaufman 1, Davide Fiscaletti 2 ABSTRACT The Minkowski formula X4=ict indicates that time t does not express the 4th dimension of space-time, i.e., X4 is not t. Therefore, Minkowski space-time is not a 3D+T manifold, it is 4D. The 4D manifold has 4 spatial dimensions and is timeless, in the sense that it does not contain some physical time in wh ich material changes run. In physics we experience the timelessness of 4D space as “Einstein’s Now.” From this perspective, the time that we measure with clocks is just the sequential numerical order of changes, i.e. motions that run in the timeless space of Now. On the other hand, past and future are nothing more than psychological or conceptual realities that derive from the neuronal activity of the brain. Therefore, “time flow” and “arrow of time” have only a mathematical existence. Key Words: Now, Time, Space, Space-Time, GPS, Closed Timeline Curve, Arrow of Time DOI Number: 10.14704/nq.201 8.16.5.1345 NeuroQuantology 2018; 16(5):23-30 Introduction system S, if complex enough, can be separated into 23 Today, 130 years after the pioneering work of a subsystem S2 whose dynamics is described, and Ernst Mach regarding the interpretation of time as another cyclic subsystem S1 which behaves as a a measure of the changes of things, the related clock and that, as a consequence of the gauge ideas that time cannot be considered as a primary invariance, this separation may be made in many physical reality that flows on its own in the ways.
    [Show full text]
  • Interpreting Supersymmetry
    Interpreting Supersymmetry David John Baker Department of Philosophy, University of Michigan [email protected] October 7, 2018 Abstract Supersymmetry in quantum physics is a mathematically simple phenomenon that raises deep foundational questions. To motivate these questions, I present a toy model, the supersymmetric harmonic oscillator, and its superspace representation, which adds extra anticommuting dimensions to spacetime. I then explain and comment on three foundational questions about this superspace formalism: whether superspace is a sub- stance, whether it should count as spatiotemporal, and whether it is a necessary pos- tulate if one wants to use the theory to unify bosons and fermions. 1 Introduction Supersymmetry{the hypothesis that the laws of physics exhibit a symmetry that transforms bosons into fermions and vice versa{is a long-standing staple of many popular (but uncon- firmed) theories in particle physics. This includes several attempts to extend the standard model as well as many research programs in quantum gravity, such as the failed supergravity program and the still-ascendant string theory program. Its popularity aside, supersymmetry (SUSY for short) is also a foundationally interesting hypothesis on face. The fundamental equivalence it posits between bosons and fermions is prima facie puzzling, given the very different physical behavior of these two types of particle. And supersymmetry is most naturally represented in a formalism (called superspace) that modifies ordinary spacetime by adding Grassmann-valued anticommuting coordinates. It 1 isn't obvious how literally we should interpret these extra \spatial" dimensions.1 So super- symmetry presents us with at least two highly novel interpretive puzzles. Only two philosophers of science have taken up these questions thus far.
    [Show full text]