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| {{Short description|Philosophical treatment of time, an object's persistence across it, and reality}} | |||
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{{other uses|Fourth dimension (disambiguation)}} | ||
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| ⚫ | {{original research|date=June 2011}} | ||
| {{essay|date=June 2011}} | {{essay|date=June 2011}} | ||
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| In ], '''four-dimensionalism''' (also known as the '''doctrine of ]''') is the ] 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.<ref name="Sider1997">{{Cite journal |title=Four-Dimensionalism |first=Theodore |last=Sider |journal=The Philosophical Review |volume=106 |issue=2 |pages=197–231 |date=April 1997 |url=http://tedsider.org/papers/4d.pdf |jstor=2998357 |doi=10.2307/2998357 |access-date=2011-06-12 |archive-url=https://web.archive.org/web/20160304074848/http://tedsider.org/papers/4d.pdf |archive-date=2016-03-04 |url-status=dead }}</ref> | |||
| It is not entirely clear, but, in ], '''four-dimensionalism''' seems to refer to what is otherwise known as ] and/or ]. The latter is a theory of time, while the former is a theory about the ] of objects over time. , for example, uses the term four-dimensionalism to refer to ], the theory that objects (and people) are four dimensional (see below for explanation). ], by contrast, is the theory that the universe (but not necessarily its contents, e.g., objects and people) is four dimensional, with time being the fourth dimension. Nevertheless, both theories tend to be discussed together, as many philosophers hold the combination of ] and ], considering both as better theories than their counterparts, ] and ], respectively. Probably, nobody who accepts ] rejects ], and it is unclear if such a position would even be coherent. | |||
| Four-dimensionalists typically argue for treating time as analogous to space, usually leading them to endorse the doctrine of '']''. This is a philosophical approach to the ontological nature of ], according to which all points in time are equally "real", as opposed to the ] idea that only the present is real.<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> As some eternalists argue by analogy, just as all spatially distant objects and events are as real as those close to us, temporally distant objects and events are as real as those currently present to us.<ref name=":0">{{Cite book|title=Metaphysics : an introduction|first=Alyssa|last=Ney|author-link=Alyssa Ney|oclc=870919144}}</ref> | |||
| ==Explanation== | |||
| The term '''four-dimensionalism''' is often used without specification of exactly what is meant. Often, it is used in the context of the issue of personal identity over time. For example, Robinson<ref>{{aut|Robinson}} (1985: 299-300)</ref> stated that 'the m.o. view, as canvassed below, is not my first choice amongst approaches to fission cases. I prefer the four-dimensionalist account (itself an m.o. analysis) presented with exemplary clarity by David Lewis in 'Survival and Identity' '. Unfortunately, David Lewis<ref></ref>, at least in the first edition of this book, does not appear to use the term '''four-dimensionalism''' at all (but see below)! Muis <ref></ref> offers an explanation of the terminology which (fairly) clearly equates '''four-dimensionalism''' with ] (by using the term 'four-dimensional' in relation to ] only), not ], but does so in an opening paragraph that mentions all four -isms (i.e., ] vs. ], ] vs. ]), stating that 'in analytical metaphysics, there are three, '''closely related''', debates about time and the nature of change and persistence' , the third debate being A-theory vs. B-theory of time (see below). Therefore, it appears to be very difficult to disentangle the issues or work out any firm terminological distinctions. It is unclear if all the literature exactly follows the terminology of Muis <ref></ref>. | |||
| '']''—or ''perdurance theory''—is a closely related philosophical theory of persistence and ],<ref name="sep-temporal-parts">{{cite encyclopedia |last=Hawley |first=Katherine |title=Temporal Parts |encyclopedia=The Stanford Encyclopedia of Philosophy |editor=Edward N. Zalta |url=http://plato.stanford.edu/archives/win2010/entries/temporal-parts/|year=2010 |edition=Winter 2010}}</ref> according to which an individual has distinct temporal parts throughout its existence, and the persisting object is the sum or set of all of its temporal parts. This sum or set is colloquially referred to as a "space-time worm", which has earned the perdurantist view the moniker of "the worm view".<ref name=":0" /> While all perdurantists are plausibly considered four dimensionalists, at least one variety of four dimensionalism does not count as perdurantist in nature. This variety, known as '''exdurantism''' or the "stage view", is closely akin to the perdurantist position. They also countenance a view of persisting objects that have temporal parts that succeed one another through time. However, instead of identifying the persisting object as the entire set or sum of its temporal parts, the exdurantist argues that any object under discussion is a single stage (time-slice, temporal part, etc.), and that the other stages or parts that comprise the persisting object are related to that part by a "temporal ]" relation.<ref>{{Cite journal|last=Sider|first=Theodore|date=1996-09-01|title=All the world's a stage|journal=Australasian Journal of Philosophy|volume=74|issue=3|pages=433–453|doi=10.1080/00048409612347421|issn=0004-8402}}</ref> | |||
| Although Lewis (1976)<ref></ref> does not use the term '''four-dimensionalism''', it is abundantly clear from a paragraph, on page 20, that he is a ]. Lewis says 'he who says that what matters in survival is a relation of mental continuity and connectedness is speaking of a relation among more-or-less momentary person-stages, or time-slices of continuant persons, or persons-at-times. He who says that what matters in survival is identity, on the other hand, must be speaking of identity among temporally extended continuant persons with stages at various times...' It ought to be remembered, however, that ] is far from being an established fact, but rather a metaphysical theory. We tend to think that there is a fundamental distinction between objects and processes (events), for example, persons and their lives. We tend to think that objects, such as people, are wholly present at each moment at which they exist (endurantism). By contrast, only a stage (=temporal part) of a process can be present at any one moment, not the whole process. Endurantism is a ] "dead end", and does not sit well with the doctrine of ]. {{Citation needed|date=June 2011}} This may seem to threaten the everyday notion that objects and people persist (i.e., retain their ] over ]). ] is an alternative to endurantism, according to which we must abandon the distinction between object and process, or, equivalently, reinterpret objects as processes. Effectively, a person '''is''' their life, with stages, and not wholly present at any one time. So, with the combination of ] and ], we can avoid the ] "dead end" theories of presentism and endurantism, while retaining ] over ] for people and objects. | |||
| Though they have often been conflated, eternalism is a theory of what time is like and what times exist, while perdurantism is a theory about persisting objects and their identity conditions over time. Eternalism and perdurantism tend to be discussed together because many philosophers argue for a combination of eternalism and perdurantism. Sider (1997)<ref name="Sider1997" /> uses the term ''four-dimensionalism'' to refer to perdurantism, but ] uses the term "four-dimensionalism" to mean the view that presentism is false as opposed to "perdurantism", the view that ] is false and persisting objects have temporal parts.<ref>{{quotation|text={{omission}} This view is variously called "four-dimensionalism", "perdurantism", or "the doctrine of temporal parts". Some think that four-dimensionalism understood as the denial of presentism implies four-dimensionalism understood as perdurantism. But whether or not that is true, the important thing to recognize is that these are two very different views. To avoid confusion, I will in this paper reserve the term "four-dimensionalism" exclusively for the view that presentism is false, and I will use the term "perdurantism" to refer to the view that objects last over time without being wholly present at every time at which they exist.|author=Michael C. Rea|title=Four Dimensionalism|source=The Oxford Handbook for Metaphysics}} </ref> | |||
| It is hard to relate the difference between ] and ] to any real life issue, but suppose that you are informed that tomorrow you will suffer the most horrendous torture. If you endure, then you will, in some sense, "find yourself" tomorrow being tortured. Better try to avoid it! But if you perdure, then you cannot "find yourself" anywhere tomorrow, for the stage of your life tomorrow is not intrinsically the "same one" (in the sense of numerical identity) as it is today, and tomorrow has no less reality today than today has! The person stage who gets told that tomorrow they will be tortured is "located in today", whereas the person stage who actually gets tortured is "located in tomorrow"! The significance of this is rather unclear, but there would seem to be far less rational reason to fear future pain if you perdure. Why should your "today stage" care about pain inflicted on your "tomorrow stage", except by way of sympathy/empathy? Issues of ] are relevant here. | |||
| == Four-dimensionalism about material objects == | |||
| {{aut|Lewis}} (1976)<ref></ref> must be understood in context. He was objecting to certain views proposed by {{aut|]}} , both philosophers being ]. {{aut|]}}, however, was more concerned with moral/ethical issues than {{aut|Lewis}}. {{aut|]}} felt the full force of materialism/perdurantism undermine our everyday notion of personal identity over time, and tried, perhaps heroically, to reconstitute morality in a world devoid of personal identity. In other words, {{aut|]}} held that our beliefs regarding personal identity over time were based on falsehoods, and tried to rescue morality in the absence of personal identity. The approach of {{aut|Lewis}} (1976), however, appears to have been to try to rescue our '''beliefs''', by trying to reconstitute personal identity over time in a materialist/four-dimensionalist world. | |||
| Four-dimensionalism is a name for different positions. One of these uses four-dimensionalism as a position of material objects with respect to dimensions. Four-dimensionalism is the view that in addition to spatial parts, objects have temporal parts.<ref>{{Cite book|title=Metaphysics: an Introduction|last=Ney|first=Alyssa|author-link=Alyssa Ney|date = 13 August 2014|isbn=978-1-317-67634-8|oclc=887509960}}</ref> | |||
| According to this view, four-dimensionalism cannot be used as a synonym for perdurantism. Perdurantists have to hold a four-dimensional view of material objects: it is impossible that perdurantists, who believe that objects persist by having different temporal parts at different times, do not believe in temporal parts. However, the reverse is not true. Four-dimensionalism is compatible with either perdurantism or exdurantism. | |||
| Eternalism is a ]/] theory about the nature of ], which has implications for the ] over ] of people and other objects. According to this theory, past, present, and future all exist equally, as opposed to the view that only the present exists, the past exists no more, and the future is yet to exist (i.e. presentism). Some philosophers, such as Markosian <ref></ref>, for example, defend presentism against objections, claiming it to be the "commonsense view", but this appears to be missing the point that, while it could be true, and while it certainly is the "commonsense view", as a theory presentism is a ] "dead end". According to eternalism, by contrast, there is nothing "special" about the present. The present is merely the temporal analogue of "here", which can be thought of as the "spatial present". Being located in the present, as opposed to the past or the future, is just like being "here rather than there". In neither case does where you are located have any "special status" over and above the fact that it is where you are located. So, in essence, ] is just a theory of time which explains away the apparent special (fundamental) status of the present (but see below). All other things being equal, it is a better theory (=better as a theory) than presentism.{{Fact|date=June 2011}} | |||
| ⚫ | ==A-series and B-series== | ||
| ==Background== | |||
| {{main article|A-series and B-series}} | |||
| As '''four-dimensionalism''' (understood as either ] or ]) is a ] theory, it is necessary to say something here about the aim of ]. Like science, the aim of ] is to understand as much as possible in terms of as little as possible. {{Citation needed|date=June 2011}} In other words, the aim is to reduce the number of fundamentals to a minimum, and understand everything else as if constructed in some simple way out of those fundamentals. If a theory of x maintains that x is a fundamental element of reality, then this is expressed in this article by saying that the theory is a ] "dead end" theory (of x). The background assumption is that reduction of fundamentals will lead to a '''true''' picture of reality. If we can understand space in terms of fundamentals x, y, z, etc., then all the better if we can also understand time in terms of x, y, z, etc. ] attempts to do just that. Time is understood as the fourth dimension, equivalent to the three dimensions of space. What we lose from this theory is any special status for the present, however special it might seem... | |||
| ] in '']'' identified two descriptions of time, which he called the A-series and the B-series. The A-series identifies positions in time as past, present, or future, and thus assumes that the "present" has some objective reality, as in both ] and the ].<ref> by Dean Zimmerman, p. 7</ref> The B-series defines a given event as earlier or later than another event, but does not assume an objective present, as in four-dimensionalism. Much of the contemporary literature in the ] of time has been taken to spring forth from this distinction, and thus takes McTaggart's work as its starting point. | |||
| ==Temporal parts== | |||
| ⚫ | ==Contrast with three-dimensionalism== | ||
| The idea of a whole object being composed of smaller parts is not revolutionary. On the contrary, this notion is rather common. One instance of a whole object losing a part is the ] example of the ]. Another illustration is a familiar routine such as getting a haircut. Both of these instances provide an example of a whole object losing a part. For the four-dimensionalist, this does not represent the notion of parthood.<ref name="Sider1997"/> | |||
| ⚫ | Unlike the four dimensionalist, the three dimensionalist considers time to be a unique ] that is not analogous to the three spatial dimensions: ], ] and ]. Whereas the four dimensionalist proposes that objects are extended across time, the three dimensionalist adheres to the belief that all objects are wholly present at any moment at which they exist. While the three dimensionalist agrees that the parts of an object can be differentiated based on their spatial dimensions, they do not believe an object can be differentiated into temporal parts across time. For example, in the three dimensionalist account, "Descartes in 1635" is the same object as "Descartes in 1620", and both are identical to Descartes, himself. However, the four dimensionalist considers these to be distinct temporal parts.<ref name="Three-Dimensionalism and Four-Dimensionalism">{{cite web |url=https://plato.stanford.edu/entries/time/#ThreDimeFourDime | ||
| The notion of parthood for a four-dimensionalist allows one to speak of the parts of an object simpliciter. That is, without any criterion or condition, versus at any particular time such as t<sub>1</sub> or t<sub>2</sub>. Within the framework of four-dimensionalism, one could say that his or her current temporal part is sitting at a computer, typing up a presentation on four-dimensionalism, wearing sweatpants and having tea. Therefore, a four-dimensionalist conceives of the parts of an object as an ] relation, or part of a larger ] worm. A spacetime worm is a four-dimensional object consisting of a three-dimensional object extending through the fourth dimension of time.<ref name="Sider1997"/> | |||
| |title=Time: 8. The 3D/4D Controversy | |||
| |date=2002-11-25 |access-date=2008-12-15 |publisher=Stanford Encyclopedia of Philosophy |quote=As in the case of the disputes between A Theorists and B Theorists, on the one hand, and Presentists and Non-presentists, on the other hand, the 3D/4D controversy is part of a general disagreement among philosophers of time concerning the degree to which time is dissimilar from the dimensions of space. That general disagreement has been an important theme in the philosophy of time during the last one hundred years, and will most likely continue to be so for some time to come.|archive-url=https://web.archive.org/web/20081007063003/http://plato.stanford.edu/entries/time#3D4Con |archive-date=2008-10-07}}</ref> | |||
| == Prominent arguments in favor of four-dimensionalism == | |||
| Furthermore, the notion of parthood allows a four-dimensionalist to account for change, in a basic and ordinary sense of the word. Change is what allows one to distinguish between different successive ] parts. For example, one temporal part of a person may be typing at a computer, while another temporal part will be going to ]. Still a third temporal part will be waking up to run ] and get prepared for work later in the evening.<ref name="Sider1997"/> | |||
| Several lines of argumentation have been advanced in favor of four-dimensionalism: | |||
| Firstly, four-dimensional accounts of time are argued to better explain paradoxes of change over time (often referred to as the paradox of the ]) than three-dimensional theories. A contemporary account of this paradox is introduced in Ney (2014),<ref name=":0" /> but the original problem has its roots in Greek antiquity. A typical Ship of Theseus paradox involves taking some changeable object with multiple material parts, for example a ship, then sequentially removing and replacing its parts until none of the original components are left. At each stage of the replacement, the ship is presumably identical with the original, since the replacement of a single part need not destroy the ship and create an entirely new one. But, it is also plausible that an object with none of the same material parts as another is not identical with the original object. So, how can an object survive the replacement of any of its parts, and in fact all of its parts? The four-dimensionalist can argue that the persisting object is a single space-time worm which has all the replacement stages as temporal parts, or in the case of the stage view that each succeeding stage bears a temporal counterpart relation to the original stage under discussion. | |||
| ==] vs. ]== | |||
| Consider the proposition: there was an American president called Reagan. What are the truth conditions? According to ], we cannot say! According to ], we can say the following: there is an American president called Reagan, in the past. We can only say that, if the past exists. How can Reagan exist in the past if the past doesn't exist? We can understand "was" in terms of "is" and "past", but only if the past exists. The past is understood as a time before the present. If you can understand the idea of someone existing in the present, and you understand the idea of a linearly ordered sequence (i.e., time), then you can understand the idea of someone existing in the past! It is just a simple set theoretic model of time. "Was" just means "is" at some point before the present (i.e., at some point before, or "less than", one's current coordinate on the time line). What is unclear, however, is that just because we '''can''' understand (model) time in this eternalist manner, does that mean that reality is really like that? Does the past really exist, and what does that mean, anyway? Or, is the model just a formal device which is useful to adopt for some theoretical purposes? Applying the model to the future does, however, seem to raise issues relating to ] and ]. | |||
| Secondly, problems of temporary intrinsics are argued to be best explained by four-dimensional views of time that involve temporal parts. As presented by ],<ref>{{Cite book|title=On the plurality of worlds|last=Lewis|first=David K.|date=1986-01-01|publisher=B. Blackwell|oclc=12236763}}</ref> the problem of temporary intrinsics involves properties of an object that are both had by that object regardless of how anything else in the world is (and thus intrinsic), and subject to change over time (thus temporary). Shape is argued to be one such property. So, if an object is capable of having a particular shape, and also changing its shape at another time, there must be some way for the same object to be, say, both round and square. Lewis argues that separate temporal parts having the incompatible properties best explains an object being able to change its shape in this way, because other accounts of three-dimensional time eliminate intrinsic properties by indexing them to times and making them relational instead of intrinsic. | |||
| ⚫ | |||
| ] famously argues in his 1908 paper ] that time is necessarily unreal. McTaggart introduces three different types of ordered relations among events: the A-series, the B-series and the C-series. The A-series is “the series of positions running from the far ] through the near past to the present, and then from the present to the near ] and the far future.” <ref name="McTaggart">{{cite web |url=http://en.wikisource.org/The_Unreality_of_Time |title=The Unreality of Time |accessdate=2008-12-15 |publisher=Wikisource}}</ref> The basic temporal distinctions of past, present and future are fundamental and unique to the A-series as well as essential to the reality of time. If the distinctions of past, present and future are not true of reality, then there is no reality in time. The A-series is championed by proponents of ].<ref name="McTaggart" /> | |||
| The B-series is a series of positions that is ordered from earlier to later. Like the A-series, the B-series contains a direction of change. Unlike the A-series, the B-series does not define a present moment that separates past and future. Events are thought to exist earlier and later, rather than in the past or future. This distinction allows one to move away from the terminology employed in the basic conception of time.<ref name="McTaggart" /> | |||
| The A-series maintains that time is running from past to future while the B-series asserts that events are running from earlier to later, therefore both require a direction. The C-series, consequently, postulates that events have an order but that there is no inherent direction of time. McTaggart asserts that the order of the events does not necessitate change, a concept that he has already established to be necessary to the concept of time. Therefore, the C-series is atemporal and offers a plausible alternative to the conventional conception of time as well as a part of the concept of ].<ref name="McTaggart" /> | |||
| ⚫ | == |
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| ⚫ | |||
| The four-dimensionalist view, by contrast, asserts that all objects occupying different ] are inherently different versions of the same object. In order to account for these different versions, the notion of temporal parts is introduced. Differences among temporal parts are how a four-dimensionalist accounts for change. Thus, the temporal part described by the phrase “] in 1635” is different from the temporal part described by the phrase “Descartes in 1620.” When combined, these parts form a ] “worm.”<ref name="3D/4D debate" /> | |||
| ==See also== | ==See also== | ||
| * ] | |||
| * ] | |||
| * ]<ref>{{aut|Lăzăroiu, A.}} 2007: Multiple occupancy, identity, and what matters. ''Philosophical explorations'', '''10'''(3): 211–225. {{doi|10.1080/13869790701535170}}</ref> | |||
| ⚫ | * ] advocating this position | ||
| * ] | |||
| * ] | |||
| * ] | |||
| ==References== | |||
| ⚫ | * ] |
||
| {{Reflist}} | |||
| == |
==Sources== | ||
| ⚫ | * Armstrong, David M. (1980) "Identity Through Time", pages 67,8 in ] (editor), ''Time and Cause'', ]. | ||
| <references /> | |||
| ⚫ | * Hughes, C. (1986) "Is a Thing Just the Sum of Its Parts?", ] 85: 213-33. | ||
| ⚫ | * Armstrong, David M. (1980) |
||
| * Heller, Mark (1984). "Temporal Parts of Four Dimensional Objects", ] 46: 323-34. Reprinted in ''Rea'' 1997: 12.-330.'' | |||
| ⚫ | * Hughes, C. (1986) |
||
| * Heller, Mark ( |
* Heller, Mark (1990) ''The Ontology of Physical Objects: Four-dimensional Hunks of Matter'', ]. | ||
| ⚫ | * Heller, Mark (1992) "Things Change", ] 52: 695-304 | ||
| sophical Studies'' 46: 323-34. Reprinted in Rea 1997: 12.-330. | |||
| * Heller, Mark ( |
* Heller, Mark (1993) "Varieties of Four Dimensionalism", ] 71: 47-59. | ||
| ⚫ | * Lewis, David (1983). "Survival and Identity", in ''Philosophical Papers, Volume 1'', 55-7. ]. With postscripts. Originally published in Amelie O. Rorty, editor (1976) ''The Identities of Persons'' ], pages 17-40. | ||
| Cambridge: Cambridge University Press. | |||
| ⚫ | * Lewis, David (1986a). '']''. Oxford: Basil Blackwell. | ||
| ⚫ | * Heller, Mark (1992) |
||
| * Heller, Mark (1993). “Varieties of Four Dimensionalism.” ''Australasian Journal of Philosophy'' 71: 47-59. | |||
| ⚫ | * Lewis, David (1983). |
||
| ⚫ | * Lewis, David (1986a). ''On the Plurality of Worlds''. Oxford: Basil Blackwell. | ||
| * Lewis, David (1986b). ''Philosophical Papers, Volume 2''. Oxford: Oxford University Press. | * Lewis, David (1986b). ''Philosophical Papers, Volume 2''. Oxford: Oxford University Press. | ||
| * McTaggart John Ellis (1908) , originally published in ] 17: 456-473. | |||
| * {{aut|Lewis, D.}} (1976) "Survival and identity", pages 17-40 in {{aut|Rorty, A.O.}} editor, ''The identities of persons''. Berkeley: University of California Press. | |||
| * {{aut| |
* {{aut|Markosian, N.}} (2004) "A defense of presentism", pages 47-82 in {{aut|Zimmerman, D.W.}} editor, ''Oxford Studies in Metaphysics'', Volume 1, Oxford University Press. | ||
| * {{aut|Muis, R.}} (2005) , '']'' 5 | |||
| * {{aut|Markosian, N.}} 2004: A defense of presentism. Pp. 47-82 ''in'' {{aut|Zimmerman, D.W.}} (ed.) ''Oxford Studies in Metaphysics'', Volume '''1'''. Oxford: Oxford University Press. | |||
| ⚫ | * {{aut|Robinson, D.}} (1985) "Can amoebae divide without multiplying?", ''Australasian Journal of Philosophy'' 63(3): 299–319. {{doi|10.1080/00048408512341901}} | ||
| * {{aut|Muis, R.}} 2005: Four-dimensionalism: an ontology of persistence and time. By Theodore Sider. ''Ars Disputandi'', '''5''' ISSN: 1566-5399 | |||
| * {{aut|Parfit, D.}} 1971: Personal identity. ''Philosophical review'', '''80'''(1): 3-27. | |||
| ⚫ | * {{aut|Robinson, D.}} 1985 |
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| ==External links== | ==External links== | ||
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Latest revision as of 16:06, 7 November 2024
Philosophical treatment of time, an object's persistence across it, and reality For other uses, see Fourth dimension (disambiguation). | This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
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In philosophy, four-dimensionalism (also known as the doctrine of temporal parts) 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.
Four-dimensionalists typically argue for treating time as analogous to space, usually leading them to endorse the doctrine of eternalism. This is a philosophical approach to the ontological nature of time, according to which all points in time are equally "real", as opposed to the presentist idea that only the present is real. As some eternalists argue by analogy, just as all spatially distant objects and events are as real as those close to us, temporally distant objects and events are as real as those currently present to us.
Perdurantism—or perdurance theory—is a closely related philosophical theory of persistence and identity, according to which an individual has distinct temporal parts throughout its existence, and the persisting object is the sum or set of all of its temporal parts. This sum or set is colloquially referred to as a "space-time worm", which has earned the perdurantist view the moniker of "the worm view". While all perdurantists are plausibly considered four dimensionalists, at least one variety of four dimensionalism does not count as perdurantist in nature. This variety, known as exdurantism or the "stage view", is closely akin to the perdurantist position. They also countenance a view of persisting objects that have temporal parts that succeed one another through time. However, instead of identifying the persisting object as the entire set or sum of its temporal parts, the exdurantist argues that any object under discussion is a single stage (time-slice, temporal part, etc.), and that the other stages or parts that comprise the persisting object are related to that part by a "temporal counterpart" relation.
Though they have often been conflated, eternalism is a theory of what time is like and what times exist, while perdurantism is a theory about persisting objects and their identity conditions over time. Eternalism and perdurantism tend to be discussed together because many philosophers argue for a combination of eternalism and perdurantism. Sider (1997) uses the term four-dimensionalism to refer to perdurantism, but Michael Rea uses the term "four-dimensionalism" to mean the view that presentism is false as opposed to "perdurantism", the view that endurantism is false and persisting objects have temporal parts.
Four-dimensionalism about material objects
Four-dimensionalism is a name for different positions. One of these uses four-dimensionalism as a position of material objects with respect to dimensions. Four-dimensionalism is the view that in addition to spatial parts, objects have temporal parts.
According to this view, four-dimensionalism cannot be used as a synonym for perdurantism. Perdurantists have to hold a four-dimensional view of material objects: it is impossible that perdurantists, who believe that objects persist by having different temporal parts at different times, do not believe in temporal parts. However, the reverse is not true. Four-dimensionalism is compatible with either perdurantism or exdurantism.
A-series and B-series
Main article: A-series and B-seriesJ.M.E. McTaggart in The Unreality of Time identified two descriptions of time, which he called the A-series and the B-series. The A-series identifies positions in time as past, present, or future, and thus assumes that the "present" has some objective reality, as in both presentism and the growing block universe. The B-series defines a given event as earlier or later than another event, but does not assume an objective present, as in four-dimensionalism. Much of the contemporary literature in the metaphysics of time has been taken to spring forth from this distinction, and thus takes McTaggart's work as its starting point.
Contrast with three-dimensionalism
Unlike the four dimensionalist, the three dimensionalist considers time to be a unique dimension that is not analogous to the three spatial dimensions: length, width and height. Whereas the four dimensionalist proposes that objects are extended across time, the three dimensionalist adheres to the belief that all objects are wholly present at any moment at which they exist. While the three dimensionalist agrees that the parts of an object can be differentiated based on their spatial dimensions, they do not believe an object can be differentiated into temporal parts across time. For example, in the three dimensionalist account, "Descartes in 1635" is the same object as "Descartes in 1620", and both are identical to Descartes, himself. However, the four dimensionalist considers these to be distinct temporal parts.
Prominent arguments in favor of four-dimensionalism
Several lines of argumentation have been advanced in favor of four-dimensionalism:
Firstly, four-dimensional accounts of time are argued to better explain paradoxes of change over time (often referred to as the paradox of the Ship of Theseus) than three-dimensional theories. A contemporary account of this paradox is introduced in Ney (2014), but the original problem has its roots in Greek antiquity. A typical Ship of Theseus paradox involves taking some changeable object with multiple material parts, for example a ship, then sequentially removing and replacing its parts until none of the original components are left. At each stage of the replacement, the ship is presumably identical with the original, since the replacement of a single part need not destroy the ship and create an entirely new one. But, it is also plausible that an object with none of the same material parts as another is not identical with the original object. So, how can an object survive the replacement of any of its parts, and in fact all of its parts? The four-dimensionalist can argue that the persisting object is a single space-time worm which has all the replacement stages as temporal parts, or in the case of the stage view that each succeeding stage bears a temporal counterpart relation to the original stage under discussion.
Secondly, problems of temporary intrinsics are argued to be best explained by four-dimensional views of time that involve temporal parts. As presented by David Lewis, the problem of temporary intrinsics involves properties of an object that are both had by that object regardless of how anything else in the world is (and thus intrinsic), and subject to change over time (thus temporary). Shape is argued to be one such property. So, if an object is capable of having a particular shape, and also changing its shape at another time, there must be some way for the same object to be, say, both round and square. Lewis argues that separate temporal parts having the incompatible properties best explains an object being able to change its shape in this way, because other accounts of three-dimensional time eliminate intrinsic properties by indexing them to times and making them relational instead of intrinsic.
See also
- Extended modal realism
- Four-dimensional space
- Multiple occupancy view
- Rietdijk–Putnam argument advocating this position
- Spacetime
- World line
- Light cone
References
- ^ Sider, Theodore (April 1997). "Four-Dimensionalism" (PDF). The Philosophical Review. 106 (2): 197–231. doi:10.2307/2998357. JSTOR 2998357. Archived from the original (PDF) on 2016-03-04. Retrieved 2011-06-12.
- Kuipers, Theo A.F. (2007). General Philosophy of Science: Focal Issues. North Holland. p. 326. ISBN 978-0-444-51548-3.
- ^ Ney, Alyssa. Metaphysics : an introduction. OCLC 870919144.
- Hawley, Katherine (2010). "Temporal Parts". In Edward N. Zalta (ed.). The Stanford Encyclopedia of Philosophy (Winter 2010 ed.).
- Sider, Theodore (1996-09-01). "All the world's a stage". Australasian Journal of Philosophy. 74 (3): 433–453. doi:10.1080/00048409612347421. ISSN 0004-8402.
-
... This view is variously called "four-dimensionalism", "perdurantism", or "the doctrine of temporal parts". Some think that four-dimensionalism understood as the denial of presentism implies four-dimensionalism understood as perdurantism. But whether or not that is true, the important thing to recognize is that these are two very different views. To avoid confusion, I will in this paper reserve the term "four-dimensionalism" exclusively for the view that presentism is false, and I will use the term "perdurantism" to refer to the view that objects last over time without being wholly present at every time at which they exist.
— Michael C. Rea, Four Dimensionalism, The Oxford Handbook for Metaphysics - Ney, Alyssa (13 August 2014). Metaphysics: an Introduction. ISBN 978-1-317-67634-8. OCLC 887509960.
- Presentism and the Space-Time Manifold by Dean Zimmerman, p. 7
- "Time: 8. The 3D/4D Controversy". Stanford Encyclopedia of Philosophy. 2002-11-25. Archived from the original on 2008-10-07. Retrieved 2008-12-15.
As in the case of the disputes between A Theorists and B Theorists, on the one hand, and Presentists and Non-presentists, on the other hand, the 3D/4D controversy is part of a general disagreement among philosophers of time concerning the degree to which time is dissimilar from the dimensions of space. That general disagreement has been an important theme in the philosophy of time during the last one hundred years, and will most likely continue to be so for some time to come.
- Lewis, David K. (1986-01-01). On the plurality of worlds. B. Blackwell. OCLC 12236763.
- Lăzăroiu, A. 2007: Multiple occupancy, identity, and what matters. Philosophical explorations, 10(3): 211–225. doi:10.1080/13869790701535170
Sources
- Armstrong, David M. (1980) "Identity Through Time", pages 67,8 in Peter van Inwagen (editor), Time and Cause, D. Reidel.
- Hughes, C. (1986) "Is a Thing Just the Sum of Its Parts?", Proceedings of the Aristotelian Society 85: 213-33.
- Heller, Mark (1984). "Temporal Parts of Four Dimensional Objects", Philosophical Studies 46: 323-34. Reprinted in Rea 1997: 12.-330.
- Heller, Mark (1990) The Ontology of Physical Objects: Four-dimensional Hunks of Matter, Cambridge University Press.
- Heller, Mark (1992) "Things Change", Philosophy and Phenomenological Research 52: 695-304
- Heller, Mark (1993) "Varieties of Four Dimensionalism", Australasian Journal of Philosophy 71: 47-59.
- Lewis, David (1983). "Survival and Identity", in Philosophical Papers, Volume 1, 55-7. Oxford University Press. With postscripts. Originally published in Amelie O. Rorty, editor (1976) The Identities of Persons University of California Press, pages 17-40.
- Lewis, David (1986a). On the Plurality of Worlds. Oxford: Basil Blackwell.
- Lewis, David (1986b). Philosophical Papers, Volume 2. Oxford: Oxford University Press.
- McTaggart John Ellis (1908) The Unreality of time, originally published in Mind: A Quarterly Review of Psychology and Philosophy 17: 456-473.
- Lewis, D. (1976) "Survival and identity", pages 17-40 in Rorty, A.O. editor, The identities of persons. Berkeley: University of California Press. Google books
- Markosian, N. (2004) "A defense of presentism", pages 47-82 in Zimmerman, D.W. editor, Oxford Studies in Metaphysics, Volume 1, Oxford University Press. Google books
- Muis, R. (2005) Review of Four-dimensionalism: an ontology of persistence and time by Theodore Sider, Ars Disputandi 5
- Robinson, D. (1985) "Can amoebae divide without multiplying?", Australasian Journal of Philosophy 63(3): 299–319. doi:10.1080/00048408512341901
External links
- Rea, M. C., "Four Dimensionalism" in The Oxford Handbook for Metaphysics. Oxford Univ. Press. Describes presentism and four-dimensionalism.
- "Time" in the Internet Encyclopedia of Philosophy
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