Eternalism (philosophy of time)

Eternalism is a philosophical 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.[1] 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.[2] 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. Within this intuitive understanding of time is the philosophy of presentism, which argues that only the present exists. It 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, the present simply 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 seems difficult to reconcile with currently accepted scientific theories such as the theory of relativity.[3]

The 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).

Special relativity eliminates the concept of absolute simultaneity and a universal present: according to the relativity of simultaneity, observers in different 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 another's. 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.[4]

Many philosophers have argued that relativity implies eternalism.[5] Philosopher of science Dean Rickles disagrees in some sense, but notes that "the consensus among philosophers seems to be that special and general relativity are incompatible with presentism."[6] Christian Wüthrich argues that supporters of presentism can only salvage absolute simultaneity if they reject either empiricism or relativity.[7] Such arguments are raised by Dean Zimmerman and others,[8] in favor of 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.[9]

The flow of time


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.[3]

Middle ages

The philosopher Katherin A. Rogers argued that Anselm of Canterbury took an eternalist view of time,[10] although the philosopher Brian Leftow argued against this interpretation,[11] suggesting that Anselm instead advocated a type of presentism. Rogers responded to this paper, defending her original interpretation.[12] 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."[13] 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.[14]

Augustine of Hippo wrote that God is 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.[15]

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.[16] 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.[3]

Dirck Vorenkamp, a professor of religious studies, argued in his paper "B-Series Temporal Order in Dogen's Theory of Time"[17] 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 reasoning also contained A-Series notions, which Vorenkamp argued may indicate some inconsistency in Dōgen's thinking.

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.[18] On the other hand, George Ellis argues that time is absent in cosmological theories because of the details they leave out.[19]

Recently Hrvoje Nikolić has argued that a block time model solves the black hole information paradox.[20]


Philosophers such as 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."[21] Similarly, Karl Popper argued in his discussion with Albert Einstein against determinism and eternalism from a common-sense standpoint.[22]

A flow-of-time theory with a strictly 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.[23]

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.[24][25] 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"[26][27] 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.[28]

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."[29] Elitzur and Shahar Dolev argue that quantum mechanical experiments such as the Quantum Liar[30] and the evaporation of black holes[31] 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.[32] 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.[33]

See also


  1. ^ Kuipers, Theo A.F. (2007). General Philosophy of Science: Focal Issues. North Holland. p. 326. ISBN 978-0-444-51548-3.
  2. ^ Tim Maudlin (2010), "On the Passing of Time", The Metaphysics Within Physics, ISBN 9780199575374
  3. ^ a b c Markosian, Ned (2014), Edward N. Zalta (ed.), "Time", The Stanford Encyclopedia of Philosophy (Fall 2016 ed.), retrieved November 18, 2017
  4. ^ Savitt, Steven F. (September 2000), "There's No Time Like the Present (in Minkowski Spacetime)", Philosophy of Science, 67 (S1): S563–S574, CiteSeerX, doi:10.1086/392846
  5. ^ Thomas M. Crisp (2007), William Lane Craig; Quentin Smith (eds.), "Presentism, Eternalism, and Relativity Physics" (PDF), Einstein, Relativity and Absolute Simultaneity, footnote 1
  6. ^ Dean Rickles (2008), Symmetry, Structure, and Spacetime, Elsevier, p. 158, ISBN 9780444531162
  7. ^ Wüthrich, Christian (2010). "No Presentism in Quantum Gravity". In Vesselin Petkov (ed.). Space, Time, and Spacetime: Physical and Philosophical Implications of Minkowski's Unification of Space and Time. Fundamental Theories of Physics. Springer. pp. 262–264. ISBN 9783642135378. LCCN 2010935080.
  8. ^ Yuri Balashov (2010), Persistence and Spacetime, Oxford University Press, p. 222
  9. ^ Zimmerman, Dean (2011). "Presentism and the Space-Time Manifold". In C. Callender (ed.). The Oxford Handbook of Philosophy of Time (PDF). Oxford Handbooks in Philosophy. OUP Oxford. pp.163-244 (PDF p.119). ISBN 9780199298204. LCCN 2011283684.
  10. ^ Katherin A. Rogers (2007). "Anselmian Eternalism". Faith and Philosophy 24 (1):3-27.
  11. ^ Brian Leftow (2009). "Anselmian Presentism. Faith and Philosophy" 26 (3):297-319.
  12. ^ Katherin Rogers (2009). "Back to Eternalism". Faith and Philosophy 26 (3):320-338.
  13. ^ Rogers, Katherin (2008). Anselm on Freedom. Oxford University Press. p. 159. ISBN 9780199231676.
  14. ^ From Kukkonen's chapter on "Eternity" in The Oxford Handbook of Medieval Philosophy edited by John Marenbon (2012), p. 529.
  15. ^ John Polkinghorne (2011). Science and Religion in Quest of Truth, p. 64.
  16. ^ J. M. E. McTaggart, "The Unreality of Time", 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.
  17. ^ Vorenkamp, Dirck (1995). "B-Series Temporal Order in Dogen's Theory of Time". Philosophy East and West, Volume 45, Number 3, 1995 July, P.387-408.
  18. ^ "Platonia", Julian Barbour's time-skeptical website
  19. ^ Ellis (2006). "Physics in the Real Universe: Time and Spacetime". Gen. Rel. Grav. 38 (12): 1797–1824. arXiv:gr-qc/0605049. Bibcode:2006GReGr..38.1797E. doi:10.1007/s10714-006-0332-z.
  20. ^ Nikolic H. (2009). "Resolving the black-hole information paradox by treating time on an equal footing with space". Phys. Lett. B. 678 (2): 218. arXiv:0905.0538. Bibcode:2009PhLB..678..218N. doi:10.1016/j.physletb.2009.06.029.
  21. ^ John LucasThe Future p8
  22. ^ Popper, K.R. (2002). Unended Quest: An Intellectual Autobiography. Routledge Classics. Routledge. pp. 148–150. ISBN 9780415285896. LCCN 2002067996.
  23. ^ "The Quantum Liar Experiment Kastner". Studies in History and Philosophy of Modern Physics. 41 (=2).
  24. ^ "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.
  25. ^ Cortês, M., & Smolin, L. (2014). "The universe as a process of unique events". Physical Review D, 90(8), 084007.
  26. ^ Smolin, L. (2015). "Temporal naturalism". Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics, 52, 86-102.
  27. ^ Smolin, L. (2018). "Temporal relationalism". arXiv preprint arXiv:1805.12468.
  28. ^ Cortês, M., & Smolin, L. (2018). "Reversing the irreversible: from limit cycles to emergent time symmetry". Physical Review D, 97(2), 026004.
  29. ^ Falk, D. (2016, July 19). A Debate Over the Physics of Time. Retrieved February 14, 2019, from
  30. ^ Elitzur, A. C., & Dolev, S. (2005). "Quantum phenomena within a new theory of time". In Quo vadis quantum mechanics? (pp. 325-349). Springer, Berlin, Heidelberg.
  31. ^ Elitzur, A. C., & Dolev, S. (1999). "Black hole evaporation entails an objective passage of time". Foundations of Physics Letters, 12(4), 309-323.
  32. ^ Elitzur, A. C., & Dolev, S. (2005). "Becoming as a bridge between quantum mechanics and relativity". In Endophysics, Time, Quantum And The Subjective: (With CD-ROM) (pp. 589-606).
  33. ^ Elitzur, A. C., & Dolev, S. (2003). "Is there more to T?. In The Nature of Time: Geometry, Physics and Perception (pp. 297-306). Springer, Dordrecht.


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

External links

Block time

Block time may refer to:

Eternalism (philosophy of time), also called "block time philosophy"

Block time of blockchains, the average time taken to create each block

Change (philosophy)

Change refers to a difference in a state of affairs at different points in time. Although it is a familiar experience, an analysis of change provides subtle problems which have occupied philosophers since the Presocratics. Heraclitus is the first philosopher known to have directly raised such issues, with aphorisms such as "one cannot step into the same river twice". The Eleatics were particularly concerned with change and raised a number of problems, including Zeno's paradoxes, which caused them to go as far as insisting that change was impossible, and that reality was one and unchanging. Later philosophers would reject this conclusion, instead developing systems such as atomism in attempts to circumvent the Eleatic problems. In the modern era, some of these problems would enter the domain of mathematics, with the development of calculus and analysis. These developments were regarded by some as solving problems of change, but others maintain that philosophical issues persist.

Clockwork universe

In the history of science, the clockwork universe compares the universe to a mechanical clock. It continues ticking along, as a perfect machine, with its gears governed by the laws of physics, making every aspect of the machine predictable.

Eternal return

Eternal return (also known as eternal recurrence) is a theory that the universe and all existence and energy has been recurring, and will continue to recur, in a self-similar form an infinite number of times across infinite time or space.

The theory is found in Indian philosophy and in ancient Egypt and was subsequently taken up by the Pythagoreans and Stoics. With the decline of antiquity and the spread of Christianity, the theory fell into disuse in the Western world, with the exception of Friedrich Nietzsche, who connected the thought to many of his other concepts, including amor fati. Eternal return relates to the philosophy of predeterminism in that people are predestined to continue repeating the same events over and over again.


The word eternalism may refer to:

Eternalism (philosophy of time), the philosophical theory which takes the view that all points in time are equally "real", as opposed to the Presentism (philosophy of time) idea that only the present is real

Positive belief in the eternity of the world or the law of conservation of energy

Eternalism is the common translation of sassatavada, the doctrine of unchanging being rejected by Buddhism

Eternalism, third album of alternative rock band The Panic Division


Eternity in common parlance is an infinitely long period of time. In classical philosophy, however, eternity is defined as what exists outside time while sempiternity is the concept that corresponds to the colloquial definition of eternity.

Eternity is an important concept in many religions, where the god or gods are said to endure eternally. Some, such as Aristotle, would say the same about the natural cosmos in regard to both past and future eternal duration, and like the eternal Platonic forms, immutability was considered essential.

Eternity of the world

The question of the eternity of the world was a concern for both ancient philosophers and the medieval theologians and philosophers of the 13th century. The question is whether the world has a beginning in time, or whether it has existed from eternity. The problem became a focus of a dispute in the 13th century, when some of the works of Aristotle, who believed in the eternity of the world, were rediscovered in the Latin West. This view conflicted with the view of the Catholic church that the world had a beginning in time. The Aristotelian view was prohibited in the Condemnations of 1210–1277.

Index of metaphysics articles

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 Ouroboros or uroborus () is an ancient symbol depicting a serpent or dragon eating its own tail. Originating in ancient Egyptian iconography, the ouroboros entered western tradition via Greek magical tradition and was adopted as a symbol in Gnosticism and Hermeticism and most notably in alchemy. The term derives from Ancient Greek: οὐροβόρος, from οὐρά (oura), "tail" + βορά (bora), "food", from βιβρώσκω (bibrōskō), "I eat".

Outline of metaphysics

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

Metaphysics – traditional branch of philosophy concerned with explaining the fundamental nature of being and the world that encompasses it, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:

What is ultimately there?

What is it like?

Static interpretation of time

The static interpretation of time is a view of time which arose in the early years of the 20th century from Einstein's special relativity and Hermann Minkowski's extension of special relativity in which time and space were famously united in physicists' thinking as spacetime.

Essentially the universe is regarded as akin to a reel of film – which is a wholly static physical object – but which when played through a movie projector conjures a world of movement, color, light and change. In the static view our whole universe – our past, present, and future are fixed parts of that reel of film, and the projector is our consciousness. But the 'happenings' of our consciousness have no objective significance – the objective universe does not happen, it simply exists in its entirety, albeit perceived from within as a world of changes.

The alternative, and commonly assumed view, is that the world unfolds in existence, that our present has some wider physical significance, because the universe evolves in step with it.

The static view is the simpler in that all that is held to exist is the physical ordering of the universe. All that there is at every time simply exists. The unfolding view requires an additional quality to the universe – that besides the physical ordering there is some quality of coming into and out of existence.

One can argue that the onus is therefore upon those who propose it, that the world unfolds, and that this additional quality they hold to (absent from special relativity) is indeed a physical feature of the world. There is however as yet no proof, experiment, or measurement, to show that our conscious experience of an unfolding present has any objective physical significance, or that the universe is anything other than static.

The static view is however commonly rejected for psychological, not scientific reasons, because it leads to a fatalistic or "fixed" conclusion about human existence – our 'past', 'present', and 'future' being what they are – there is no contingency in the world and no possibility of 'altering' or creating the future through some act of will – the future exists. It is simply that our consciousness has not yet reached it.

General terms and concepts
Time travel in fiction
Temporal paradoxes
Parallel timelines
Philosophy of space and time
Spacetimes in general relativity that
can contain closed timelike curves
Key concepts
Measurement and
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Human experience
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