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B-theory of time

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The B-theory of time is a name given to one of two positions in the philosophy of time. B-theorists believe that time is tenseless, rather than tensed. Theories such as four-dimensionalism and eternalism draw upon the B-theory.

Origin

J.M.E. McTaggart, who cointed the term "B-theory of time".

The labels, A-theory and B-theory, are derived from the analysis of time and change developed by Cambridge philosopher J. M. E. McTaggart in 'The Unreality of Time' (1908), in which events are ordered via a tensed A-series or a tenseless B-series. A-series is closely related to presentism while B-series is closely related to eternalism.[1]

Events (or 'times'), McTaggart observed, may be characterized in two distinct, but related, ways. On the one hand they can be characterized as past, present or future, normally indicated in natural languages such as English by the verbal inflection of tenses or auxiliary adverbial modifiers. Alternatively events may be described as earlier than, simultaneous with, or later than others. Philosophers are divided as to whether the tensed or tenseless mode of expressing temporal fact is fundamental.[1] To assert that both are equally fundamental is to land in McTaggert's Paradox, since it would require of any event that it is both present and future, which is contradictory.[2]

Those who (like Arthur Prior[3]) take the tensed notions associated with the past, present and future to be the irreducible foundations of temporality and our conceptions of temporal fact, are called A-theorists (similar to presentists). A-theorists deny that past, present and future are equally real, and maintain that the future is not fixed and determinate like the past. A-theorists also believe that a satisfactory account of time must acknowledge a fundamental metaphysical difference between past, present and future.[4] Those who wish to eliminate all talk of past, present and future in favour of a tenseless ordering of events are called B-theorists (such as D.H. Mellor[5] and J.J.C. Smart[6]), who believe that the past, the present, and the future are equally real. B-theorists concede that the distinction between past, present, and future is central to our concept of time, but argue that this concept is not self-evidently correct.[7]

B-theory in metaphysics

A-theorists believe that a satisfactory account of time must acknowledge a fundamental metaphysical difference between past, present and future.[8] The difference between A-theorists and B-theorists is often described as a dispute about temporal passage or 'becoming' and 'progressing'. B-theorists argue that this notion is purely psychological, and embodies serious confusion about time. B-theorists also argue that The past, the present, and the future feature very differently in deliberation and reflection. We remember the past and anticipate the future, for example, but not vice versa. B-theorists maintain that the fact that we know much less about the future simply reflects an epistemological difference between the future and the past: the future is no less real than the past; we just know less about it.[9] Many A-theorists argue that in rejecting temporal 'becoming', B-theorists reject time's most vital and distinctive characteristic.[10] It is common (though not universal) to identify A-theorists' views with belief in temporal passage.[1]

The debate between A-theorists and B-theorists is a continuation of a metaphysical dispute reaching back to the ancient Greek philosophers Heraclitus and Parmenides.[11] Parmenides thought that reality is timeless and unchanging.[12] Heraclitus, in contrast, believed that the world is a process of ceaseless change, flux and decay.[13] Reality for Heraclitus is dynamic and ephemeral. Indeed the world is so fleeting, according to Heraclitus, that it is impossible to step twice into the same river.[14] The metaphysical issues that continue to divide A-theorists and B-theorists concern the reality of the past, the reality of the future, and the ontological status of the present.

B-theory in theoretical physics

B-theorists argue that in special relativity, the relativity of simultaneity implies there is not a unique present, and many of special relativity's counter-intuitive predictions such as length contraction and time dilation are a result of this. Relativity of simultaneity implies eternalism (a block universe) and hence a B-theory of time, where the present for different observers is a time slice of the four dimensional universe. Thus it is also common (though not universal) for B-theorists to be four-dimensionalists, that is, to believe that objects are extended in time as well as in space and therefore have temporal as well as spatial parts. This is sometimes called a time-slice ontology.[15]

A-theorists will counter in one of two ways, depending on how philosophically rich that the B-theorist intends special relativity to be.[16] They can deny the special theory of relativity, for example, arguing that special relativity gave way to general relativity, which has cosmic time that can serve as the absolute 'now'.[17][18][19] A-theorists can also argue that special relativity does not imply that there is no absolute simultaneity.[1] For example, an A-theorist might argue that the neo-Lorentzian interpretation of relativity, which is empirically equivalent to the Spacetime (Minkowskian) interpretation,[20] is correct. Under the neo-Lorentzian model, there is a privileged time and reference frame. Distances shrink up and clocks slow down for objects in motion relative to said frame. [21][22] Mellor states that "while it is physically possible to determine whether two objects or events are simultaneous relative to a particular frame of reference, it is not physically possible to determine whether two objects or events are absolutely simultaneous."[23] Therefore, special relativity is consistent with absolute simultaneity. It is also consistent with absolute presentness.[24]

A-theorists have argued that relativity is even more compatible with relativity than the B-theory is. Geoffrey Builder has also argued that the non-relativity of rotation and acceleration imply the existence of absolute space and time, giving support to the neo-Lorentzian theory.[25] In arguing for this model, Simon Prohovnik states that time dilation and length contraction "are by no means independent and that both may in fact be consequential on a single more fundamental concept."[26] Ettore Minguzzi and Alan Macdonald suggest that the existence of a frame of reference where the speed of light has a round-trip speed of c, regardless of the motion of its source, is that one fundamental concept which explains both time dilation and length contraction on a neo-Lorentzian model.[27]

Criticism

Opponents, such as philosopher and theologian William Lane Craig, argue that the B-theory of time is burdened with heavy philosophical problems. Craig objects that on the B-theory, temporal becoming is an entirely subjective phenomenon, and hence not an objective feature of reality. In the absence of minds, every temporal moment and event simply exists tenselessly; there are no tensed facts; no past, present, or future; nothing comes into existence or happens except in the tenseless sense of existing at certain appointed stations as opposed to others. If the mental phenomenon of temporal becoming is an objective feature of reality, this amounts to a denial of the B-theory of time.[28] If the B-theorist bites the bullet, stating that there is no temporal becoming of mental states, then this flies in the face of experience. In support of this view, Craig cites early 20th century astronomer and physicist Sir Arthur Eddington who stated: "We have direct insight into 'becoming' which sweeps aside all symbolic knowledge as on an inferior plane. If I grasp the notion of existence because I myself exist, I grasp the notion of becoming because I myself become. It is the innermost Ego of all that is and becomes."[29][30] However, one might still claim that the passing of time – which is the change in "present" moment – can be slower or faster, which likely depends on the amount of man's consciousness inserted between two moments.

Craig objects that B-theory suffers the same incoherence as all theories that time is illusory, namely, that an illusion or appearance of becoming involves becoming, so that becoming cannot be mere illusion or appearance. The idealist or phenomenalist can consistently deny the reality of the physical world, since the illusion of physicality does not entail physicality, but this is not the case with temporal becoming.[31] As an example, Craig cites early 20th century philosopher John Laird who wrote: "Take the supposed illusion of change. This must mean that something, X, appears to change when in fact it does not change at all. That may be true about X; but how could the illusion occur unless there were change somewhere? If there is no change in X, there must be a change in the deluded mind that contemplates X. The illusion of change is actually a changing illusion. Thus the illusion of change implies the reality of some change. Change, therefore, is invincible in its stubbornness; for no one can deny the appearance of change."[32][33]

Examples in fiction

The idea behind a B-theory of time and consequently four-dimensionalism and eternalism, are demonstrated in the film Interstellar. The physics of Interstellar was based on the work of renowned physicist Kip Thorne.[34] Astronaut Cooper is sent to a region of space called a 'tesseract', built by beings of 5-dimesnions. In the tesseract, Cooper is able to perceive all of time simultaneously, and is consequently able to transmit information back to a time in his perceived past. According to the B-theory of time, this is consistent and does not induce a paradox.

Notes

  1. ^ a b c d Markosian, Ned. "Time". Stanford Encyclopedia of Philosophy. Retrieved 28 December 2014.
  2. ^ Callender, Craig (September 1, 2000). "Shedding Light on Time". Philosophy of Science. 67. {{cite journal}}: |access-date= requires |url= (help)
  3. ^ Template:Fr icon http://hylo.loria.fr/content/papers/files/tense.pdf
  4. ^ Prior, Arthur N. (2010). Papers on time and tense (New ed. ed.). Oxford [u.a.]: Oxford University Press. p. 5. ISBN 0199256071. {{cite book}}: |edition= has extra text (help)
  5. ^ "Philosophy Cambridge Mellor Time Tense". People.pwf.cam.ac.uk. Retrieved 2014-03-03.
  6. ^ "Google Drive Viewer". Docs.google.com. Retrieved 2014-03-03.
  7. ^ Mellor, D. H. (1998). Real time II ([Online-Ausg.]. ed.). London: Routledge. p. 7. ISBN 0415097819. {{cite book}}: |access-date= requires |url= (help)
  8. ^ Prior, Arthur N. (2010). Papers on time and tense (New ed. ed.). Oxford [u.a.]: Oxford University Press. p. 5. ISBN 0199256071. {{cite book}}: |edition= has extra text (help)
  9. ^ Mellor, D. H. (1998). Real time II ([Online-Ausg.]. ed.). London: Routledge. p. 21. ISBN 0415097819. {{cite book}}: |access-date= requires |url= (help)
  10. ^ McTaggart, J. Ellis (1908). "The Unreality of Time". Mind (68): 458. {{cite journal}}: |access-date= requires |url= (help)
  11. ^ Craig, William Lane (2011). The tenseless theory of time : a critical examination. Dordrecht: Springer. p. 22. ISBN 904815586X. {{cite book}}: |access-date= requires |url= (help)
  12. ^ Palmer, John. "Parmenides". Stanford Encyclopedia of Philosophy. Retrieved 29 December 2014.
  13. ^ Graham, Daniel W. "Heraclitus". Stanford Encyclopedia of Philosophy. Retrieved 29 December 2014.
  14. ^ This sentence has been translated by Seneca in Epistulae, VI, 58, 23.
  15. ^ Clark, Michael (May 1978). "Time-slices of particular continuants as basic individuals: An impossible ontology". Philosophical Studies. 33 (4): 403. {{cite journal}}: |access-date= requires |url= (help)
  16. ^ Zimmerman, edited by Dean W. (2004). Oxford studies in metaphysics (1. publ. ed.). Oxford: Oxford University Press. p. 74. ISBN 0199267723. {{cite book}}: |first1= has generic name (help)
  17. ^ Craig, William Lane (1990). "God and Real Time". Religious Studies: 335. {{cite journal}}: |access-date= requires |url= (help)
  18. ^ Primack, Joel R.; Abrams, Nancy Ellen. "The Age of the Universe — Measuring Cosmic Time". Retrieved 28 December 2014.
  19. ^ "Cosmic Time". Einstein Online. Retrieved 28 December 2014.
  20. ^ Lorentz, Hendrik Antoon (1922). Lecture on theoretical physics, Vol.3 (Lectures held between 1910–1912, first published in Dutch in 1922, English translation in 1931). London: MacMillan.
  21. ^ Prokhovnik, S.J. (1979). "An introduction to the neo-Lorentzian relativity of Builder". Speculations in science and technology. 2 (3).
  22. ^ Craig, William Lane. "Response to McCall and Balashov".
  23. ^ Zimmerman, edited by Dean W. (2004). Oxford studies in metaphysics (1. publ. ed.). Oxford: Oxford University Press. p. 75. ISBN 0199267723. {{cite book}}: |first1= has generic name (help)
  24. ^ Zimmerman, edited by Dean W. (2004). Oxford studies in metaphysics (1. publ. ed.). Oxford: Oxford University Press. p. 75. ISBN 0199267723. {{cite book}}: |first1= has generic name (help)
  25. ^ Builder, Geoffrey (September 1958). "Ether and Relativity". Australian Journal of Physics. 11 (3): 279. {{cite journal}}: |access-date= requires |url= (help)
  26. ^ Prohovnik, Simon. "The Case for an Aether". The British Journal for the Philosophy of Science. 14 (55): 195. {{cite journal}}: |access-date= requires |url= (help)
  27. ^ Minguzzi, Ettore; Macdonald, Alan (2003). "Universal One - Way Light Speed from a Universal Light Speed Over Closed Paths". Foundations of Physics Letters. 16 (6): 593. {{cite journal}}: |access-date= requires |url= (help)
  28. ^ Craig, William Lane (2000). The tenseless theory of time : a critical examination. Dordrecht [u.a.]: Kluwer Acad. Publ. ISBN 978-0792366355.
  29. ^ Eddington, Arthur (1928). Nature of the Physical World: Gifford Lectures. Cambridge, UK: Cambridge University Press. p. 7. ISBN 978-1-107-66385-5.
  30. ^ Craig, William Lane (2000). The Tenseless Theory of Time: A Critical Examination. Dordrecht [u.a.]: Kluwer Acad. Publ. p. 171. ISBN 978-0792366355.
  31. ^ Craig, William Lane (2000). The tenseless theory of time : a critical examination. Dordrecht [u.a.]: Kluwer Acad. Publ. p. 176. ISBN 978-0792366355.
  32. ^ Laird, John (1940). Theism and Cosmology, Being the First Series of a Course of Gifford Lectures on the General Subject of Metaphysics and Theism Given in the University of Glasgow in 1939. London, UK: George Allen and Unwin Ltd. p. 145. ISBN 978-0-415-65969-7.
  33. ^ Craig, William Lane (2000). The Tenseless Theory of Time: A Critical Examination. Dordrecht [u.a.]: Kluwer Acad. Publ. p. 176. ISBN 978-0792366355.
  34. ^ "New 'Interstellar' Trailer Goes Deep; Plus Kip Thorne Featurette". /Film. October 1, 2014. Retrieved October 5, 2014.

References

  • Clark, M. (1978) 'Time-slices of particular continuants as basic individuals: An impossible ontology'. Philosophical Studies 33, 403–408.
  • Craig, W.L. (2001) The Tensed Theory of Time: A Critical Examination. Synthese Library.
  • Craig, W.L. (2000) The Tenseless Theory of Time: A Critical Examination. Synthese Library.
  • Davies, Paul (1980) Other Worlds. Harmondsworth: Penguin.
  • McTaggart, J.M.E. (1908) 'The Unreality of Time', Mind 17: 457-73.
  • McTaggart, J.M.E. (1927) The Nature of Existence, Vol II. Cambridge: Cambridge University Press.
  • Mellor, D.H. (1998) Real Time II. London: Routledge.
  • Prior, A.N. (2003) Papers on Time and Tense. New Edition by Per Hasle, Peter Øhrstrøm, Torben Braüner & Jack Copeland. Oxford: Clarendon.
  • Putnam, H. (2005) 'A Philosopher Looks at Quantum Mechanics Again', British Journal for the Philosophy of Science, 56, pp 615 – 634.
  • Quine, W. V. O. (1960) Word and Object, Cambridge, MA: M.I.T. Press.
  • Markosian, Ned, 2002, "Time", Stanford Encyclopedia of Philosophy
  • Arthur Prior, Stanford Encyclopedia of Philosophy
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