B-theory of time

Last updated

The B-theory of time, also called the "tenseless theory of time", is one of two positions regarding the temporal ordering of events in the philosophy of time. B-theorists argue that the flow of time is only a subjective illusion of human consciousness, that the past, present, and future are equally real, and that time is tenseless: temporal becoming is not an objective feature of reality. Therefore, there is nothing privileged about the present, ontologically speaking. [1]

Contents

The B-theory is derived from a distinction drawn by J. M. E. McTaggart between A series and B series. The B-theory is often drawn upon in theoretical physics, [2] and is seen in theories such as eternalism.

Origin of terms

The terms A-theory and B-theory, first coined by Richard Gale in 1966, [3] derive from Cambridge philosopher J. M. E. McTaggart's analysis of time and change in "The Unreality of Time" (1908), in which events are ordered via a tensed A-series or a tenseless B-series. It is popularly assumed that the A theory represents time like an A-series, while the B theory represents time like a B-series. [4] The terms A and B theory are sometimes used as synonyms to the terms presentism and eternalism, but arguably[ original research? ][ citation needed ] presentism does not represent time being like an A-series since it denies that there is a future and past in which events can be located.

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. [4] Some philosophers have criticised hybrid theories, where one holds a tenseless view of time but asserts that the present has special properties, as falling foul of McTaggart's paradox. [5] For a thorough discussion of McTaggart's paradox, see R. D. Ingthorsson (2016). [6]

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. [1] [7] Parmenides thought that reality is timeless and unchanging. [8] Heraclitus, in contrast, believed that the world is a process of ceaseless change or flux. [9] 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. [10] 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 metaphysics

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. [11] Many A-theorists argue that in rejecting temporal 'becoming', B-theorists reject time's most vital and distinctive characteristic. [12] It is common (though not universal) to identify A-theorists' views with belief in temporal passage. [4] Another way to characterise the distinction revolves around what is known as the principle of temporal parity, the thesis that contrary to what appears to be the case, all times really exist in parity[ definition needed ]. A-theory (and especially presentism) denies that all times exist in parity, while B-theory insists all times exist in parity. [13] [6]

B-theorists such as D. H. Mellor [14] and J. J. C. Smart [15] wish to eliminate all talk of past, present and future in favour of a tenseless ordering of events, believing the past, present, and future to be equally real, opposing the idea that they are irreducible foundations of temporality. B-theorists also argue that the past, present, and future feature very differently in deliberation and reflection. For example, we remember the past and anticipate the future, 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. [16]

B-theory in theoretical physics

The B-theory of time has received support from physicists. [17] [18] This is likely due to its compatibility with physics and the fact that many theories such as special relativity, the ADD model, and brane cosmology, point to a theory of time similar to B-theory.

In special relativity, the relativity of simultaneity shows that there is no unique present, and that each point in the universe can have a different set of events that are in its present moment.

Many of special relativity's now-proven counterintuitive predictions, such as length contraction and time dilation, are a result of this. Relativity of simultaneity is often taken to imply eternalism (and hence a B-theory of time), where the present for different observers is a time slice of the four-dimensional universe. This is demonstrated in the Rietdijk–Putnam argument and in Roger Penrose's advanced form of this argument, the Andromeda paradox. [19]

It is therefore 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. [20]

Opposition

Irreducibility of tense

Earlier B-theorists argued that one could paraphrase tensed sentences (such as "the sun is now shining", uttered on September 28) into tenseless sentences (such as "on September 28, the sun shines") without loss of meaning. [21] [22] Later B-theorists argued that tenseless sentences could give the truth conditions of tensed sentences or their tokens. [23] [24] Quentin Smith argues that "now" cannot be reduced to descriptions of dates and times, because all date and time descriptions, and therefore truth conditionals, are relative to certain events. Tensed sentences, on the other hand, do not have such truth conditionals. [25] The B-theorist could argue that "now" is reducible to a token-reflexive phrase such as "simultaneous with this utterance", yet Smith states that even such an argument fails to eliminate tense. One can think the statement "I am not uttering anything now", and such a statement would be true. The statement "I am not uttering anything simultaneous with this utterance" is self-contradictory, and cannot be true even when one thinks the statement. [26] Finally, while tensed statements can express token-independent truth values, no token-reflexive statement can do so (by definition of the term "token-reflexive"). [27] Smith claims that proponents of the B-theory argue that the inability to translate tensed sentences into tenseless sentences does not prove A-theory. [28]

Logician and philosopher Arthur Prior has also drawn a distinction between what he calls A-facts and B-facts. The latter are facts about tenseless relations, such as the fact that the year 2025 is 25 years later than the year 2000. The former are tensed facts, such as that the Jurassic age is in the past, or that the end of the universe is in the future. Prior asks the reader to imagine having a headache, and after the headache subsides, saying "thank goodness that's over." Prior argues that the B-theory cannot make sense of this sentence. It seems bizarre to be thankful that a headache is earlier than one's utterance, anymore than being thankful that the headache is later than one's utterance. Indeed, most people who say "thank goodness that's over" are not even thinking of their own utterance. Therefore, when people say "thank goodness that's over," they are thankful for an A-fact, and not a B-fact. Yet, A-facts are only possible on the A-theory of time. [29] (See also: Further facts.)

Endurantism and perdurantism

Opponents also charge the B-theory with being unable to explain persistence of objects. The two leading explanations for this phenomenon are endurantism and perdurantism. According to the former, an object is wholly present at every moment of its existence. According to the latter, objects are extended in time and therefore have temporal parts. [30] [31] Hales and Johnson explain endurantism as follows: "something is an enduring object only if it is wholly present at each time in which it exists. An object is wholly present at a time if all of its parts co-exist at that time." [32] Under endurantism, all objects must exist as wholes at each point in time, but an object such as a rotting fruit will have the property of being not rotten one day and being rotten on another. On eternalism, and hence the B-theory, it seems that one is committed to two conflicting states for the same object. [30] The spacetime (Minkowskian) interpretation of relativity adds an additional problem for endurantism under B-theory. On the spacetime interpretation, an object may appear as a whole at its rest frame, but on an inertial frame, it will have proper parts at different positions, and therefore different parts at different times. Hence it will not exist as a whole at any time, contradicting endurantism. [33]

Opponents will then charge perdurantism with numerous difficulties of its own. First, it is controversial whether perdurantism can be formulated coherently. An object is defined as a collection of spatiotemporal parts, defined as pieces of a perduring object. If objects have temporal parts, this leads to difficulties. For example, the rotating discs argument asks the reader to imagine a world containing nothing more than a homogeneous spinning disk. Under endurantism, the same disc endures despite its rotations. The perdurantist supposedly has a difficult time explaining what it means for such a disc to have a determinate state of rotation. [34] Temporal parts also seem to act unlike physical parts. A piece of chalk can be broken into two physical halves, but it seems nonsensical to talk about breaking it into two temporal halves. [35] American epistemologist Roderick Chisholm argued that someone who hears the bird call "Bob White" knows "that his experience of hearing 'Bob' and his experience of hearing 'White' were not also had by two other things, each distinct from himself and from each other. The endurantist can explain the experience as "There exists an x such that x hears 'Bob' and then x hears 'White'" but the perdurantist cannot give such an account. [36] Peter van Inwagen asks the reader to consider Descartes as a four-dimensional object that extends from 1596 to 1650. If Descartes had lived a much shorter life, he would have had a radically different set of temporal parts. This diminished Descartes, he argues, could not have been the same person on perdurantism, since their temporal extents and parts are so different. [37]

Notes

  1. 1 2 Craig, W. L. (2000). The Tenseless Theory of Time: A Critical Examination. Dordrecht: Kluwer Academic Publishers. ISBN   0792366352.
  2. ↑ "Brian Greene on the B-theory of time" https://www.youtube.com/watch?v=H1WfFkp4puw
  3. ↑ Gale, Richard (April 1966). "McTaggart's Analysis of Time". American Philosophical Quarterly. 3 (2): 145–152. JSTOR   20009201.
  4. 1 2 3 Markosian, Ned. "Time". Stanford Encyclopedia of Philosophy. Retrieved 28 December 2014.
  5. ↑ Callender, Craig (September 1, 2000). "Shedding Light on Time". Philosophy of Science. 67: S587–S599. doi:10.1086/392848. S2CID   120906143.
  6. 1 2 Ingthorsson, R. D. (2016). McTaggart's Paradox. New York: Routledge. ISBN   978-1-138-67724-1.
  7. ↑ Smart, J.J.C. (2010). Time and Cause Essays Presented to Richard Taylor. Springer Verlag. p. 7. ISBN   978-9048183586.
  8. ↑ Palmer, John (8 February 2008). "Parmenides". Stanford Encyclopedia of Philosophy. Retrieved 29 December 2014.
  9. ↑ Graham, Daniel W. "Heraclitus". Stanford Encyclopedia of Philosophy. Retrieved 29 December 2014.
  10. ↑ This sentence has been translated by Seneca in Epistulae, VI, 58, 23.
  11. ↑ Harrington, James. "What "Becomes" in Temporal Becoming?". American Philosophical Quarterly. 46 (3): 249.
  12. ↑ McTaggart, J. Ellis (1908). "The Unreality of Time". Mind (68): 458.
  13. ↑ Carter, William R.; Hestevold, H. Scott (1994). "On Passage and Persistence". American Philosophical Quarterly. 31 (4): 269–283. JSTOR   20009790.
  14. ↑ "Philosophy Cambridge Mellor Time Tense". People.pwf.cam.ac.uk. Retrieved 2014-03-03.
  15. ↑ "Google Drive Viewer" . Retrieved 2014-03-03.
  16. ↑ Mellor, D. H. (1998). Real time II ([Online-Ausg.]. ed.). London: Routledge. p.  21. ISBN   0415097819.
  17. ↑ "Brian Green on B-theory of time" https://www.youtube.com/watch?v=H1WfFkp4puw
  18. ↑ "Prof. Brian Greene: Past, present and future exist now" https://www.youtube.com/watch?v=f9AiPuIsqck/
  19. ↑ Penrose, R. (1989). The Emperor's New Mind : "Concerning Computers, Minds, and Laws of Physics". New York and Oxford: Oxford University Press.
  20. ↑ Clark, Michael (May 1978). "Time-slices of particular continuants as basic individuals: An impossible ontology". Philosophical Studies. 33 (4): 403–408. doi:10.1007/bf00354208. S2CID   170267880.
  21. ↑ Williams, Clifford. "'Now', Extensional Interchangeability, and the Passage of Time". Philosophical Forum. 5: 405.
  22. ↑ Fisk, Milton. "A Pragmatic Account of Tenses". American Philosophical Quarterly. 8.
  23. ↑ Smart, J.J.C. (2010). Time and Cause Essays Presented to Richard Taylor. Springer Verlag. p. 11. ISBN   978-9048183586.
  24. ↑ Beer, Michelle (1988). "Temporal Indexicals and the Passage of Time". Philosophical Quarterly. 38 (151): 158–164. doi:10.2307/2219921. JSTOR   2219921.
  25. ↑ Smith, Quentin (1993). Language and time ([1. paperback issue] ed.). Oxford: Oxford University Press. p. 35. ISBN   0195082273.
  26. ↑ Smith, Quentin (1993). Language and time ([1. paperback issue] ed.). Oxford: Oxford University Press. p. 79. ISBN   0195082273.
  27. ↑ Smith, Quentin (1993). Language and time ([1. paperback issue] ed.). Oxford: Oxford University Press. p. 83. ISBN   0195082273.
  28. ↑ Smith, Quentin (1993). Language and time ([1. paperback issue] ed.). Oxford: Oxford University Press. p. 3. ISBN   0195082273.
  29. ↑ Markosian, John W. Carroll, Ned (2010). An introduction to metaphysics (1. publ., repr. ed.). New York: Cambridge University Press. pp.  169–170. ISBN   978-0521533683.{{cite book}}: CS1 maint: multiple names: authors list (link)
  30. 1 2 Hawley, Katherine (2020). Temporal Parts. Metaphysics Research Lab, Stanford University.{{cite book}}: |website= ignored (help)
  31. ↑ Lewis, David (2001). On the Plurality of Worlds ([Reprint.] ed.). Malden, Mass. [u.a.]: Blackwell Publishers. p.  202. ISBN   0631224262.
  32. ↑ Hales, Steven D.; Johnson, Timothy A. "Endurantism, Perdurantism, and Special Relativity". The Philosophical Quarterly. 53 (213): 532.
  33. ↑ Hales, Steven D.; Johnson, Timothy A. "Endurantism, Perdurantism, and Special Relativity". The Philosophical Quarterly. 53 (213): 535.
  34. ↑ Teller, Paul (2002). "The Rotating Disc Argument and Humean Supervenience". Analysis. 62 (3): 206–207. doi:10.1093/analys/62.3.205.
  35. ↑ Thomson, Judith Jarvis. "Parthood and Identity Across Time". Journal of Philosophy: 80.
  36. ↑ Muniz, Milton K., ed. (June 1971). Identity and Individuation. New York University Press. p. 15. ISBN   0814753752.
  37. ↑ Van Inwagen, Peter (1990). "Four-Dimensional Objects". Noûs: 252–254.

Related Research Articles

Process philosophy, also ontology of becoming, or processism, is an approach in philosophy that identifies processes, changes, or shifting relationships as the only real experience of everyday living. In opposition to the classical view of change as illusory or accidental, process philosophy posits transient occasions of change or becoming as the only fundamental things of the ordinary everyday real world.

<span class="mw-page-title-main">Eternalism (philosophy of time)</span> Philosophical view that there is no correct way of perceiving the passage of time

In the philosophy of space and time, eternalism is an approach to the ontological nature of time, which takes the view that all existence in time is equally real, as opposed to presentism or the growing block universe theory of time, in which at least the future is not the same as any other time. Some forms of eternalism give time a similar ontology to that of space, as a dimension, with different times being as real as different places, and future events are "already there" in the same sense other places are already there, and that there is no objective flow of time.

<span class="mw-page-title-main">William Lane Craig</span> American philosopher and theologian (born 1949)

William Lane Craig is an American analytic philosopher, Christian apologist, author, and Wesleyan theologian who upholds the view of Molinism and neo-Apollinarianism. He is a professor of philosophy at Houston Christian University and at the Talbot School of Theology of Biola University.

Truthmaker theory is "the branch of metaphysics that explores the relationships between what is true and what exists". The basic intuition behind truthmaker theory is that truth depends on being. For example, a perceptual experience of a green tree may be said to be true because there actually is a green tree. But if there were no tree there, it would be false. So the experience by itself does not ensure its truth or falsehood, it depends on something else. Expressed more generally, truthmaker theory is the thesis that "the truth of truthbearers depends on the existence of truthmakers". A perceptual experience is the truthbearer in the example above. Various representational entities, like beliefs, thoughts or assertions can act as truthbearers. Truthmaker theorists are divided about what type of entity plays the role of truthmaker; popular candidates include states of affairs and tropes.

Philosophy of space and time is the branch of philosophy concerned with the issues surrounding the ontology and epistemology of space and time. While such ideas have been central to philosophy from its inception, the philosophy of space and time was both an inspiration for and a central aspect of early analytic philosophy. The subject focuses on a number of basic issues, including whether time and space exist independently of the mind, whether they exist independently of one another, what accounts for time's apparently unidirectional flow, whether times other than the present moment exist, and questions about the nature of identity.

<span class="mw-page-title-main">Kalam cosmological argument</span> Philosophical argument for the existence of God

The Kalam cosmological argument is a modern formulation of the cosmological argument for the existence of God. It is named after the Kalam, from which its key ideas originated. William Lane Craig was principally responsible for giving new life to the argument in the 20th century, due to his book The Kalām Cosmological Argument (1979), among other writings.

"The Unreality of Time" is the best-known philosophical work of University of Cambridge idealist J. M. E. McTaggart (1866–1925). In the argument, first published as a journal article in Mind in 1908, McTaggart argues that time is unreal because our descriptions of time are either contradictory, circular, or insufficient. A slightly different version of the argument appeared in 1927 as one of the chapters in the second volume of McTaggart's greatest work, The Nature of Existence.

Perdurantism or perdurance theory is a philosophical theory of persistence and identity. The debate over persistence currently involves three competing theories—one three-dimensionalist theory called "endurantism" and two four-dimensionalist theories called "perdurantism" and "exdurantism". For a perdurantist, all objects are considered to be four-dimensional worms and they make up the different regions of spacetime. It is a fusion of all the perdurant's instantaneous time slices compiled and blended into a complete mereological whole. Perdurantism posits that temporal parts alone are what ultimately change. Katherine Hawley in How Things Persist states that change is "the possession of different properties by different temporal parts of an object".

Philosophical presentism is the view that only present entities exist. According to presentism, there are no past or future entities. In a sense, the past and the future do not exist for presentists—past events have happened and future events will happen, but neither exist at all since they do not exist now. Presentism is a view about temporal ontology that contrasts with eternalism—the view that past, present and future entities exist —and with no-futurism—the view that only past and present entities exist.

In metaphysics, the A series and the B series are two different descriptions of the temporal ordering relation among events. The two series differ principally in their use of tense to describe the temporal relation between events and the resulting ontological implications regarding time.

In philosophy, the term formal ontology is used to refer to an ontology defined by axioms in a formal language with the goal to provide an unbiased view on reality, which can help the modeler of domain- or application-specific ontologies to avoid possibly erroneous ontological assumptions encountered in modeling large-scale ontologies.

In philosophy, four-dimensionalism is the ontological position that an object's persistence through time is like its extension through space. Thus, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies, just like an object that exists in a region of space has at least one part in every subregion of that space.

In contemporary metaphysics, temporal parts are the parts of an object that exist in time. A temporal part would be something like "the first year of a person's life", or "all of a table from between 10:00 a.m. on June 21, 1994 to 11:00 p.m. on July 23, 1996". The term is used in the debate over the persistence of material objects. Objects typically have parts that exist in space—a human body, for example, has spatial parts like hands, feet, and legs. Some metaphysicists believe objects have temporal parts as well.

In philosophy, mereological essentialism is a mereological thesis about the relationship between wholes, their parts, and the conditions of their persistence. According to mereological essentialism, objects have their parts necessarily. If an object were to lose or gain a part, it would cease to exist; it would no longer be the original object but a new and different one.

Endurantism or endurance theory is a philosophical theory of persistence and identity. According to the endurantist view, material objects are persisting three-dimensional individuals wholly present at every moment of their existence, which goes with an A-theory of time. This conception of an individual as always present is opposed to perdurantism or four-dimensionalism, which maintains that an object is a series of temporal parts or stages, requiring a B-theory of time. The use of "endure" and "perdure" to distinguish two ways in which an object can be thought to persist can be traced to David Lewis.

Metaphysics is the branch of philosophy that investigates principles of reality transcending those of any particular science. Cosmology and ontology are traditional branches of metaphysics. It is concerned with explaining the fundamental nature of being and the world. Someone who studies metaphysics can be called either a "metaphysician" or a "metaphysicist".

The following outline is provided as an overview of and topical guide to metaphysics:

<span class="mw-page-title-main">Hopi time controversy</span> Academic debate about conceptualization of time in Hopi language

The Hopi time controversy is the academic debate about how the Hopi language grammaticizes the concept of time, and about whether the differences between the ways the English and Hopi languages describe time are an example of linguistic relativity or not. In popular discourse the debate is often framed as a question about whether the Hopi have a concept of time.

<span class="mw-page-title-main">Tim Maudlin</span> American philosopher of science (born 1958)

Tim William Eric Maudlin is an American philosopher of science who has done influential work on the metaphysical foundations of physics and logic.

<span class="mw-page-title-main">Donald Cary Williams</span> American philosopher

Donald Cary Williams, usually cited as D. C. Williams, was an American philosopher and a professor at both the University of California Los Angeles and at Harvard University.

References

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.