Editing Eternalism (philosophy of time)

{{Short description|Philosophical view that there is no correct way of perceiving the passage of time}}

[[File:Illustration of block universe.svg|thumb|Illustration of the concept of eternalism, showing a man walking his dog. Time progresses through the series of snapshots from the bottom of the page to the top. In a common sense view of time, each of those four instants would exist one after another. According to eternalism, those four instants all equally exist.]]

In the [[philosophy of space and time]], '''eternalism'''<ref>{{cite journal |last1=Le Bihan |first1=Baptiste |title=String theory, loop quantum gravity and eternalism |journal=European Journal for Philosophy of Science |date=2020 |volume=10 |issue=2 |pages=17 |arxiv=2005.09335 |doi=10.1007/s13194-020-0275-3|s2cid=210958803 }}</ref> is an approach to the [[ontology|ontological]] nature of [[time]], which takes the view that all existence in time is equally ''real'', as opposed to [[Presentism (philosophy of time)|presentism]] or the [[growing block universe]] theory of time, in which at least the future is not the same as any other time.<ref>{{Cite book|title=General Philosophy of Science: Focal Issues |first=Theo A.F.|last=Kuipers|publisher=North Holland|year=2007|isbn=978-0-444-51548-3|page=326|url=https://books.google.com/books?id=qUMuFaXjNjEC&pg=PA326}}</ref> 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 [[objectivity (science)|objective]] flow of time.<ref>{{citation|author=Tim Maudlin|author-link=Tim Maudlin|title=The Metaphysics Within Physics|isbn=9780199575374|year=2010|chapter=On the Passing of Time|publisher=Oxford University Press }}</ref>

It is sometimes referred to as the "'''block time'''" or "'''block universe'''" theory due to its description of [[space-time]] as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time.

==The present==

In classical philosophy, time is divided into three distinct regions: the "[[past]]", the "[[present]]", and the "[[future]]". Using that representational model, the past is generally seen as being immutably fixed, and the future as at least partly undefined. As time passes, the moment that was once the present becomes part of the past, and part of the future, in turn, becomes the new present. In this way time is said to pass, with a distinct present moment moving forward into the future and leaving the past behind. One view of this type, [[Presentism (philosophy of time)|presentism]], argues that only the present exists. The present does not travel forward through an environment of time, moving from a real point in the past and toward a real point in the future. Instead, it merely changes. The past and future do not exist and are only concepts used to describe the real, isolated, and changing present. This conventional model presents a number of difficult philosophical problems and may be difficult to reconcile with currently accepted scientific theories such as the [[theory of relativity]].<ref name="SEP-time">{{citation|last1=Markosian |first1=Ned |author-link=Ned Markosian |title=Time |year=2014 |encyclopedia=The Stanford Encyclopedia of Philosophy |edition=Fall 2016 |editor=Edward N. Zalta |url=https://plato.stanford.edu/archives/fall2016/entries/time/ |access-date=November 18, 2017}}</ref>

[[File:BarAndRing.svg|thumb|right|180px|The [[Ladder paradox#Bar and ring paradox|bar and ring paradox]] is an example of the [[relativity of simultaneity]]. Both ends of the bar pass through the ring simultaneously in the rest frame of the ring (left), but the ends of the bar pass one after the other in the rest frame of the bar (right).]]
It can be argued that [[special relativity]] eliminates the concept of absolute simultaneity and a universal present: according to the [[relativity of simultaneity]], observers in different [[Frame of reference|frames of reference]] can have different measurements of whether a given pair of events happened at the same time or at different times, with there being no physical basis for preferring one frame's judgments over those of another. However, there are events that may be non-simultaneous in all frames of reference: when one event is within the [[light cone]] of another—its causal past or causal future—then observers in all frames of reference show that one event preceded the other. The causal past and causal future are consistent within all frames of reference, but any other time is "elsewhere", and within it there is no present, past, or future. There is no physical basis for a set of events that represents the present.<ref name="Savitt">{{citation|last1=Savitt|first1=Steven F.|title=There's No Time Like the Present (in Minkowski Spacetime)|doi=10.1086/392846|journal=Philosophy of Science|volume=67|issue=S1|date=September 2000|pages=S563–S574|citeseerx=10.1.1.14.6140|s2cid=121275903}}</ref>

Many philosophers have argued that relativity implies eternalism.<ref>{{citation|author=Thomas M. Crisp|url=http://people.biola.edu/thomasc/thomasmcrisp/Vita_files/Presentism,%20Eternalism%20and%20Relativity%20Physics.pdf|title=Presentism, Eternalism, and Relativity Physics|work=Einstein, Relativity and Absolute Simultaneity|year=2007|editor1=William Lane Craig|editor2=Quentin Smith|at=footnote 1|access-date=2012-08-07|archive-url=https://web.archive.org/web/20110428024231/http://people.biola.edu/thomasc/thomasmcrisp/Vita_files/Presentism,%20Eternalism%20and%20Relativity%20Physics.pdf|archive-date=2011-04-28|url-status=dead}}</ref> Philosopher of science Dean Rickles says that, "the consensus among philosophers seems to be that special and general relativity are incompatible with presentism."<ref>{{citation|author=Dean Rickles|year=2008|title=Symmetry, Structure, and Spacetime|page=158|isbn=9780444531162|publisher=[[Elsevier]]}}</ref> Christian Wüthrich argues that supporters of presentism can salvage absolute simultaneity only if they reject either [[empiricism]] or relativity.<ref name="Wuthrich2010">{{cite book |first=Christian |last=Wüthrich |year=2010 |chapter=No Presentism in Quantum Gravity |title=Space, Time, and Spacetime: Physical and Philosophical Implications of Minkowski's Unification of Space and Time |editor= Vesselin Petkov|series=Fundamental Theories of Physics |publisher=Springer |isbn=9783642135378 |lccn=2010935080 |url= http://philsci-archive.pitt.edu/5363/|pages=[https://books.google.com/books?id=t35AR6–F5QQC&pg=PA262 262–264]}}</ref> [[Dean Zimmerman (philosopher)|Dean Zimmerman]] and others argue for [[Absolute space and time|a single privileged frame]] whose judgments about length, time, and simultaneity are the ''true'' ones, even if there is no empirical way to distinguish this frame.<ref name="Zimmerman2011">{{cite book |first=Dean |last=Zimmerman |editor= C. Callender |year=2011 |title=The Oxford Handbook of Philosophy of Time |chapter=Presentism and the Space-Time Manifold |series=Oxford Handbooks in Philosophy |publisher=OUP Oxford |isbn=9780199298204 |lccn=2011283684 |url=http://fas-philosophy.rutgers.edu/zimmerman/Presentism%20and%20Rel.for.Web.2.pdf |at=pp.163-244 (PDF p.119)}}</ref><ref>{{citation|author=Yuri Balashov|title=Persistence and Spacetime|year=2010|publisher=Oxford University Press|page=222}}</ref> [[Hilary Putnam]] concluded in 1967 that it follows from special relativity that ″any future event ''X'' is already real″ and eternalism is the only view compatible with special relativity.<ref>{{citation|author=Hilary Putnam|title=Time and physical geometry|year=1967|publisher=The Journal of Philosophy|volume=64|issue=8|page=140-147}}</ref> The philosopher Mauro Dorato interprets Putnam's arguments differently and asserts that ″the opposition between presentism − only the presently existing
event exist − and eternalism − past present and future events are equally real − which is
somewhat presupposed in Putnam 1967, is misguided.″<ref>{{citation|author=Mauro Dorato|title=Putnam on Time and Special Relativity: A Long Journey from Ontology to Ethics|year=2006|publisher=European Journal of Analytic Philosophy|volume=4|issue=2|page=51-70}}</ref>

== The flow of time ==
=== Antiquity ===
Arguments for and against an independent flow of time have been raised since antiquity, represented by [[fatalism]], [[reductionism]], and [[Platonism]]: Classical fatalism argues that every [[proposition]] about the future exists, and it is either true or false, hence there is a set of every true proposition about the future, which means these propositions describe the future exactly as it is, and this future is true and unavoidable. Fatalism is challenged by positing that there are propositions that are neither true nor false, for example they may be indeterminate. Reductionism questions whether time can exist independently of the relation between events, and Platonism argues that time is absolute, and it exists independently of the events that occupy it.<ref name="SEP-time" />

Earlier, pre-Socratic Greek philosopher [[Parmenides]] of Elea had posited that existence is timeless and change is impossible (an idea popularized by his disciple [[Zeno of Elea]] and [[Zeno's paradoxes|his paradoxes about motion]]).

=== Middle ages ===
The philosopher Katherin A. Rogers argued that [[Anselm of Canterbury]] took an eternalist view of time,<ref>Katherin A. Rogers (2007). [http://philpapers.org/rec/ROGAEA "Anselmian Eternalism"]. Faith and Philosophy 24 (1):3-27.</ref> although the philosopher [[Brian Leftow]] argued against this interpretation,<ref>Brian Leftow (2009). [http://philpapers.org/rec/LEFAP-2 "Anselmian Presentism. Faith and Philosophy"] 26 (3):297-319.</ref> suggesting that Anselm instead advocated a type of presentism. Rogers responded to this paper, defending her original interpretation.<ref>Katherin Rogers (2009). [http://philpapers.org/rec/ROGBTE "Back to Eternalism"]. Faith and Philosophy 26 (3):320-338.</ref> Rogers also discusses this issue in her book ''Anselm on Freedom'', using the term "four-dimensionalism" rather than "eternalism" for the view that "the present moment is not ontologically privileged", and commenting that "[[Boethius]] and Augustine do sometimes sound rather four-dimensionalist, but Anselm is apparently the first consistently and explicitly to embrace the position."<ref>{{cite book |first=Katherin |last=Rogers |year=2008 |title=Anselm on Freedom |publisher=Oxford University Press |isbn=9780199231676 |url=https://books.google.com/books?id=lg-swy7JcEAC&pg=PA159 |page=159}}</ref> Taneli Kukkonen argues in the ''Oxford Handbook of Medieval Philosophy'' that "what Augustine's and Anselm's mix of eternalist and presentist, tenseless and tensed language tells is that medieval philosophers saw no need to choose sides" the way modern philosophers do.<ref>From Kukkonen's chapter on "Eternity" in ''The Oxford Handbook of Medieval Philosophy'' edited by John Marenbon (2012), [https://books.google.com/books?id=2TbPp5I6nL8C&pg=PA529 p. 529].</ref>

[[Augustine of Hippo]] wrote that [[God]] is [[eternity|outside of time]]—that time exists only within the created universe.  [[Thomas Aquinas]] took the same view, and many theologians agree.  On this view, God would perceive something like a block universe, while time might appear differently to the finite beings contained within it.<ref>John Polkinghorne (2011). ''Science and Religion in Quest of Truth'', [https://books.google.com/books?id=pdeUz0_WXP8C&pg=PA64 p. 64].</ref>

=== Modern period ===
One of the most famous arguments about the nature of time in modern philosophy is presented in ''[[The Unreality of Time]]'' by [[J. M. E. McTaggart]].<ref name=McT>J. M. E. McTaggart, "The Unreality of Time", ''[[Mind (journal)|Mind]]'' 17: 457–73; reprinted in J. M. E. McTaggart, ''The Nature of Existence'', Vol. 2, 1927, Cambridge: Cambridge University Press: Book 5, Chapter 33.</ref> It argues that time is an illusion. McTaggart argued that the description of events as existing in absolute time is self-contradictory, because the events have to have properties about being in the past and in the future, which are incompatible with each other. McTaggart viewed this as a contradiction in the concept of time itself, and concluded that reality is non-temporal. He called this concept the [[B-theory of time]].<ref name="SEP-time" />

Dirck Vorenkamp, a professor of religious studies, argued in his paper "B-Series Temporal Order in Dogen's Theory of Time"<ref>Vorenkamp, Dirck (1995). [https://web.archive.org/web/20101206055549/http://ccbs.ntu.edu.tw/FULLTEXT/JR-PHIL/dirck.htm "B-Series Temporal Order in Dogen's Theory of Time"]. ''Philosophy East and West'', Volume 45, Number 3, 1995 July, P.387-408.</ref> that the [[Zen]] Buddhist teacher [[Dōgen]] presented views on time that contained all the main elements of McTaggart's B-series view of time (which denies any objective present), although he noted that some of Dōgen's reasoning also contained A-Series notions, which Vorenkamp argued may indicate some inconsistency in Dōgen's thinking.

Eternalism also encapsulates the theory of world lines, and the concept of linear reality that is - the individual perception of linear time.<ref>{{cite book |last1=Schneider |first1=Susan |title=Science Fiction and Philosophy:From Time Travel To SuperIntelligence |date=2016 |publisher=John Wiley&Sons |isbn=9781405149075 |pages=370–384 |edition=2nd}}</ref>

=== Quantum physics ===

Some philosophers appeal to a specific theory that is "timeless" in a more radical sense than the rest of physics, the theory of [[quantum gravity]]. This theory is used, for instance, in [[Julian Barbour]]'s theory of timelessness.<ref>{{cite book |last=Barbour |first=Julian |date=1999 |title=The End of Time |publisher=Oxford University Press |isbn=0195145925 }}</ref> On the other hand, George Ellis argues that time is absent in cosmological theories because of the details they leave out.<ref>{{cite journal |last=Ellis |first=George F. R. |doi=10.1007/s10714-006-0332-z |journal=General Relativity and Gravitation |volume=38 |title=Physics in the Real Universe: Time and Spacetime |issue=12 |pages=1797–1824 |year=2006 |arxiv=gr-qc/0605049 |bibcode=2006GReGr..38.1797E |s2cid=119540219 }}</ref>

Recently, Hrvoje Nikolić has argued that a block time model solves the [[black hole information paradox]].<ref>{{cite journal |last=Nikolić |first=Hrvoje |doi=10.1016/j.physletb.2009.06.029 |journal=Physics Letters B |title=Resolving the black-hole information paradox by treating time on an equal footing with space |volume=678 |issue=2 |pages= 218–221 |year=2009 |arxiv=0905.0538|bibcode=2009PhLB..678..218N |s2cid=15074164 }}</ref>

== Objections ==

Philosophers such as [[John Lucas (philosopher)|John Lucas]] argue that "The Block universe gives a deeply inadequate view of time. It fails to account for the passage of time, the pre-eminence of the present, the directedness of time and the difference between the future and the past."<ref>[[John Lucas (philosopher)|John Lucas]]''The Future'' p8</ref> Similarly, [[Karl Popper]] argued in his discussion with [[Albert Einstein]] against determinism and eternalism from a common-sense standpoint.<ref name="Popper2002">{{cite book |first=K.R. |last=Popper |year=2002 |title=Unended Quest: An Intellectual Autobiography |series=Routledge Classics |publisher=Routledge |isbn=9780415285896 |lccn=2002067996 |url=https://books.google.com/books?id=CxND59gFftMC&pg=PA148 |pages=148–150}}</ref>

A flow-of-time theory with a strictly [[determinism|deterministic]] future, which nonetheless does not exist in the same sense as the present, would not satisfy common-sense intuitions about time. Some have argued that common-sense flow-of-time theories can be compatible with eternalism, for example [[John G. Cramer]]’s [[transactional interpretation]]. Kastner (2010) "proposed that in order to preserve the elegance and economy of the interpretation, it may be necessary to consider offer and confirmation waves as propagating in a “higher space” of possibilities.<ref name="Kastner2010">{{cite journal |title=The Quantum Liar Experiment Kastner|journal=Studies in History and Philosophy of Modern Physics |volume=41| issue = 2}}</ref>

In ''[[Time Reborn]]'', [[Lee Smolin]] argues that time is physically fundamental, in contrast to Einstein's view that time is an illusion. Smolin hypothesizes that the laws of physics are not fixed, but rather evolve over time via a form of cosmological natural selection.<ref>"Time Reborn: a new theory of time - a new view of the world". Royal Society of Arts. May 21, 2013. Archived from the original on July 28, 2013.</ref><ref>{{cite journal |last1=Cortês |first1=Marina |last2=Smolin |first2=Lee |title=The universe as a process of unique events |journal=Physical Review D |date=6 October 2014 |volume=90 |issue=8 |pages=084007 |arxiv=1307.6167 |doi=10.1103/PhysRevD.90.084007|bibcode=2014PhRvD..90h4007C |s2cid=118557476 }}</ref> In ''[[The Singular Universe and the Reality of Time]]'', co-authored with philosopher [[Roberto Mangabeira Unger]], Smolin goes into more detail on his views on the physical passage of time. In contrast to the orthodox block universe view, Smolin argues that what instead exists is a "thick present"<ref>{{cite journal |last1=Smolin |first1=Lee |title=Temporal naturalism |journal=Studies in History and Philosophy of Science Part B |date=2015 |volume=52 |pages=86–102 |arxiv=1310.8539 |doi=10.1016/j.shpsb.2015.03.005|bibcode=2015SHPMP..52...86S |s2cid=8344858 }}</ref><ref>{{cite book |last=Smolin |first=Lee |chapter=Temporal Relationalism |editor1=Nick Huggett |editor2=Keizo Matsubara |editor3=Christian Wuthrich|title=Beyond Spacetime |date=30 April 2020 |pages=143–175 |arxiv=1805.12468 |doi=10.1017/9781108655705.010|isbn=9781108655705 |s2cid=118936279 }}</ref> in which two events in the present can be causally related to each other. Marina Cortês and Lee Smolin also argue that certain classes of discrete dynamical systems demonstrate time asymmetry and irreversibility, which is inconsistent with the block universe interpretation of time.<ref>{{cite journal |last1=Cortês |first1=Marina |last2=Smolin |first2=Lee |title=Reversing the irreversible: From limit cycles to emergent time symmetry |journal=Physical Review D |date=10 January 2018 |volume=97 |issue=2 |pages=026004 |arxiv=1703.09696 |doi=10.1103/PhysRevD.97.026004|bibcode=2018PhRvD..97b6004C |s2cid=119067096 }}</ref>

[[Avshalom Elitzur]] vehemently rejects the block universe interpretation of time. At the Time in Cosmology conference, held at the [[Perimeter Institute for Theoretical Physics]] in 2016, Elitzur said: "I’m sick and tired of this block universe, ... I don’t think that next Thursday has the same footing as this Thursday. The future does not exist. It does not! Ontologically, it’s not there."<ref>Falk, D. (2016, July 19). A Debate Over the Physics of Time. Retrieved February 14, 2019, from https://www.quantamagazine.org/a-debate-over-the-physics-of-time-20160719/</ref> Elitzur and Shahar Dolev argue that quantum mechanical experiments such as the Quantum Liar<ref>{{cite book |last1=Elitzur |first1=Avshalom C. |last2=Dolev |first2=Shahar |chapter=Quantum Phenomena Within a New Theory of Time |chapter-url=https://www.researchgate.net/publication/226976724 |title=Quo Vadis Quantum Mechanics? |series=The Frontiers Collection |date=2005 |pages=325–349 |doi=10.1007/3-540-26669-0_17|isbn=3-540-22188-3 }}</ref> and the evaporation of black holes<ref>{{cite journal |last1=Elitzur |first1=Avshalom C. |last2=Dolev |first2=Shahar |title=Black Hole Evaporation Entails an Objective Passage of Time |journal=Foundations of Physics Letters |date=1999 |volume=12 |issue=4 |pages=309–323 |arxiv=quant-ph/0012081 |doi=10.1023/A:1021644319368|bibcode=1999FoPhL..12..309E |s2cid=15532826 }}</ref> challenge the mainstream block universe model, and support the existence of an objective passage of time. Elitzur and Dolev believe that an objective passage of time and relativity can be reconciled, and that it would resolve many of the issues with the block universe and the conflict between relativity and quantum mechanics.<ref>{{cite book |last1=Elitzur |first1=Avshalom C. |last2=Dolev |first2=Shahar |chapter=Becoming as a bridge between quantum mechanics and relativity |chapter-url=https://www.researchgate.net/publication/228343669 |title=Endophysics, Time, Quantum and the Subjective |date=2005 |pages=589–606 |doi=10.1142/9789812701596_0031|isbn=978-981-256-509-9 }}</ref> Additionally, Elitzur and Dolev believe that certain quantum mechanical experiments provide evidence of apparently inconsistent histories, and that spacetime itself may therefore be subject to change affecting entire histories.<ref>{{cite book |last1=Elitzur |first1=A. C. |last2=Dolev |first2=S. |year=2003 |arxiv=quant-ph/0207029 |chapter=Is there more to T |title=The Nature of Time: Geometry, Physics and Perception |pages=297–306 |publisher=Springer |location=Dordrecht}}</ref>

Some philosophers have made objections to eternalism based on the existence of the self and concepts such as Benj Hellie's [[vertiginous question]]. Vincent Conitzer argues that arguments in favor of the A-theory of time are more effective as arguments for the combined position of both A-theory being true and the "I" being metaphysically privileged from other perspectives.<ref>{{cite arXiv|last=Conitzer|first=Vincent|author-link=|date=30 Aug 2020|title=The Personalized A-Theory of Time and Perspective|eprint=2008.13207v1|class=physics.hist-ph}}</ref> Similar arguments have been made by Caspar Hare with the theories of [[egocentric presentism]] and [[perspectival realism]].

==See also==
* [[A series and B series]]
* [[Arrow of time]]
* [[Centered world]]
* [[Eternity of the world]]
* [[Imaginary time]]
* [[Philosophical presentism]]
* [[Philosophy of space and time]]
* [[Problem of time]]
* [[Steady state]]
* [[Steady-state model]]
* [[Strata-cut animation]]

==References==
{{Reflist}}

==Bibliography==
* Smart, Jack. "River of Time". In Anthony Kenny. Essays in Conceptual Analysis. pp.&nbsp;214–215.
* van Inwagen, Peter (2008). "Metaphysics." Stanford Encyclopedia of Philosophy.

==External links==
* {{cite journal|author1=Biswas|author2=Shaw|author3=Modak|doi=10.1142/S0218271801001384|journal= International Journal of Modern Physics D|volume=10|title=Time in Quantum Gravity|issue=4|pages=595–606|year=1999|arxiv=gr-qc/9906010|bibcode=2001IJMPD..10..595B|s2cid=119472003}}
* {{cite journal| title=That Mysterious Flow| journal=Scientific American|date=September 2002| volume=287| issue=3| pages=40–45| first=Paul| last=Davies| doi=10.1038/scientificamerican0902-40| pmid=12197100| bibcode=2002SciAm.287c..40D}}
* {{cite encyclopedia| url=http://plato.stanford.edu/entries/time/#3D4Con| title=Time: 8. The 3D/4D Controversy| encyclopedia=Stanford Encyclopedia of Philosophy| access-date=2006-12-20| year=2002| first=Ned| last= Markosian}}
* {{cite web| url=http://fqxi.org/data/essay-contest-files/Nikolic_FQXi_time.pdf|
first= Hrvoje| last= Nikolic| title= Block time: Why many physicists still don't accept it?}}
* Slavov, Matias (2024) "[https://iep.utm.edu/eternalism/ Eternalism]" ''The Internet Encyclopedia of Philosophy''. ISSN 2161-0002. 
{{Time travel}}
{{Time Topics}}
{{Time in philosophy}}

[[Category:Philosophy of physics]]
[[Category:Philosophy of time]]
[[Category:Theories of time]]