How do things persist? Are material objects spread out through time just as they are spread out through space? Or is temporal persistence quite different from spatial extension? This key question lies at the heart of any metaphysical exploration of the material world, and it plays a crucial part in debates about personal identity and survival. This book explores and compares three theories of persistence — endurance, perdurance, and stage theories — investigating the ways in which they attempt to account (...) for the world around us. Having provided valuable clarification of its two main rivals, the book concludes by advocating stage theory. Such a basic issue about the nature of the physical world naturally has close ties with other central philosophical problems. This book includes discussions of change and parthood, of how we refer to material objects at different times, of the doctrine of Humean supervenience, and of the modal features of material things. In particular, it contains new accounts of the nature of worldly vagueness, and of what binds material things together over time, distinguishing the career of a natural object from an arbitrary sequence of events. Each chapter concludes with a reflection about the impact of these metaphysical debates upon questions about our personal identity and survival. (shrink)

This is a revised and expanded edition of a seminal work in the logic and philosophy of time, originally published in 1968. Arthur N. Prior (1914-1969) was the founding father of temporal logic, and his book offers an excellent introduction to the fundamental questions in the field. Several important papers have been added to the original selection, as well as a comprehensive bibliography of Prior's work and an illuminating interview with his widow, Mary Prior. In addition, the Polish logic which (...) made Prior's writings difficult for many readers has been replaced by standard logical notation. This new edition will secure the classic status of the book. (shrink)

I offer a new criticism of the argument from vagueness to four-dimensionalism [Sider 2001. The argument is modelled after an older argument for mereological universalism [Lewis 1986 and may be looked upon as a tightened-up and extended version of the latter. While I agree with other critics [Koslicki 2003; Markosian 2004 that the argument from vagueness fails precisely because of this affinity, my recipe for dealing with it is different. I reject the assumption, shared by Sider with his opponents, that (...) synchronic composition and ‘minimal diachronic fusion’ are sufficiently similar to use considerations inspired by the analysis of the former to bear on the latter. My objection to a crucial premise of the argument from vagueness turns on the relevant aspect of dissimilarity between these two cases. (shrink)

This is a study of the nature of time. In it, redeploying an argument first presented by McTaggart, the author argues that although time itself is real, tense is not. He accounts for the appearance of the reality of tense - our sense of the passage of time, and the fact that our experience occurs in the present - by showing how time is indispensable as a condition of action. Time itself is further analysed, and Dr Mellor gives answers to (...) most of the metaphysical questions it provokes, concerning the relation of time to space, the dissection of time, and its relation to change and causation. (shrink)

This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

_'Philosophy, from the earliest times, has made greater claims, and acheived fewer results than any other branch of learning... I believe that the time has now arrived when this unsatisfactory state of affairs can be brought to an end'_ - _Bertrand Russell_ So begins _Our Knowledge of the Eternal World_, Bertrand Russell's classic attempt to show by means of examples, the nature, capacity and limitations of the logico-analytical method in philosophy.

Our model of time is the classical continuum of real numbers, and our model of other measurable quantities that change over time is that of functions defined on real numbers with real numbers as values. This model is not derived from reality or from our experience of it, but imposed on reality; and the fit is very imperfect. In classical mathematics, the value of a function for any real number as argument is independent of its value for any other argument: (...) the analogue is Hume's doctrine that events are loose and separate. This makes continuity in the change of any quantity a contingent law of physica, rather than a conceptual necessity. The article explores alternatives to this classical model. (shrink)

This book is a systematic history of one of the oldest problems in the philosophy of space and time: How is the change from one state to its opposite to be described? To my knowledge it is the first comprehensive book providing information about and analysis of texts on this topic throughout the ages. The target audience I envisaged are advanced students and scholars of analytic philosophy and the history of philosophy who are interested in the philosophy of space and (...) time. Authors treated in this book range from Plato, Aristotle, the logicians of the late Middle Ages, Kant, Brentano and Russell to contemporary authors such as Chisholm, Hamblin, Sorabji or Graham Priest, taking into account such theories as interval semantics or paraconsistent logic. For the first time, two main questions about the moment of change are explicitly kept apart: Which of the opposite states does the moment of change belong to? And does it contain an instantaneous event? The texts are discussed within a clear framework of the main systematic options for describing the moment of change, sometimes using predicate logic extended by newly introduced logical prefixes. The last part contains a new suggestion of how to solve the problem of the moment of change. It is centred around a theory of instantaneous states which provides a new solution to Zeno's Flying Arrow Paradox. (shrink)

In the course of the discussion, Professor Quine pinpoints the difficulties involved in translation, brings to light the anomalies and conflicts implicit in our ...

The stage theory is a four-dimensional account of persistence motivatedby the worm theory's inability to account for our intuitions in thecases involving coinciding objects. Like the worm theory, it claimsthat there are objects spread out in time, but unlike the worm theory,it argues that these spacetime worms are not familiar particulars liketables and chairs. Rather, familiar particulars are the instantaneoustemporal slices of worms. In order to explain our intuitions that particulars persist for more than an instant, the stage theory drawson (...) the counterpart theory of modal possibilism, which it is supposedto parallel. In this paper I show how the stage theory presupposes thattime can be divided into instants, which I call the atomistic view oftime. I do this by laying out an alternative theory of the nature oftime, the gunky view, and show that if time is gunky the stage theorycollapses into the worm theory. The deeper problem is that the merepossibility of gunky time would cause the stage theory's parallels topossibilism to break down. I therefore conclude that the stage theoryis committed to the view that time is necessarily atomistic. Finally,in the last section I argue that the fact that the stage theory rulesout a priori the possibility of time being gunky gives us reason toreject it as an account of persistence. (shrink)

Richard Sorabji here takes time as his central theme, exploring fundamental questions about its nature: Is it real or an aspect of consciousness? Did it begin along with the universe? Can anything escape from it? Does it come in atomic chunks? In addressing these and myriad other issues, Sorabji engages in an illuminating discussion of early thought about time, ranging from Plato and Aristotle to Islamic, Christian, and Jewish medieval thinkers. Sorabji argues that the thought of these often negelected philosophers (...) about the subject is, in many cases, more complete than that of their more recent counterparts. “Splendid. . . . The canvas is vast, the picture animated, the painter nonpareil. . . . Sorabji’s work will encourage more adventurers to follow him to this fascinating new-found land.”—Jonathan Barnes, Times Literary Supplement “One of the most important works in the history of metaphysics to appear in English for a considerable time. No one concerned with the problems with which it deals either as a historian of ideas or as a philosopher can afford to neglect it.”—Donald MacKinnon, Scottish Journal of Theology “Unusually readable for such scholarly content, the book provides in rich and cogent terms a lively and well-balanced discussion of matters of concern to a wide academic audience.”— Choice. (shrink)

Persistence through time is like extension through space. A road has spatial parts in the subregions of the region of space it occupies; likewise, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies. This view — known variously as four dimensionalism, the doctrine of temporal parts, and the theory that objects “perdure” — is opposed to “three dimensionalism”, the doctrine that things “endure”, or are “wholly present”.1 I will (...) attempt to resolve this dispute in favor of four dimensionalism by means of a novel argument based on considerations of vagueness. But before argument in this area can be productive, I believe we must become much clearer than is customary about exactly what the dispute is, for the usual ways of formulating the dispute are flawed, especially where three dimensionalism is concerned. (shrink)

A. N. Prior; XIV—Time, Existence and Identity, Proceedings of the Aristotelian Society, Volume 66, Issue 1, 1 June 1966, Pages 183–192, https://doi.org/10.1093/.

Are we the people we were? If we are continuants, then the answer to this question is an affirmative one. But it is a moot point whether anything is a continuant. The debate over this issue—of whether there are such things as continuants—is often conducted in the context of theories concerning the apparent passage of time. Thus it has been argued that the tenseless theory of time, according to which time does not really pass, forces us to tear down part (...) of the basis for the intuitive distinction between ordinary, reidentifiable objects on the one hand, and processes on the other, and to regard such objects as mountains as persisting through time in exactly the way that thunderstorms do: by having distinct temporal parts at different times. I confess that I am a tenseless theorist of time, and take that theory to entail such a conclusion about the persistence of objects. But it is not just a certain stance over time’s passage that motivates sympathy towards temporal parts and suspicion of continuants. Thinking of objects as having temporal parts sits more comfortably than does the rival view with two natural assumptions concerning continuity: that beginning and ceasing to exist, at least for most objects, involves underlying changes which are continuous in nature; and that objects exhibit continuity through time, in the sense of not having gaps in their existence. Or so I shall argue in what follows. (shrink)

Sider’s (2001) modification of the Lewisean argument from vagueness for unrestricted mereological composition is advertised as having the advantage over the original that the assumption of the semantic determinacy of ‘part of’ (its lack of multiple eligible precisifications) is not required. This is not so; without this assumption the crucial step in Sider’s defence of his most contentious premiss, (P3), is one no defender of the linguistic theory of vagueness is obliged to take. Since the aim of the argument is (...) precisely to show that a defender of the linguistic theory of vagueness must accept unrestricted mereological composition the argument has no advantage over Lewis’s. (shrink)

There’s an argument around from so-called “linguistic theories of vagueness”, plus some relatively uncontroversial considerations, to powerful metaphysical conclusions. David Lewis employs this argument to support the mereological principle of unrestricted composition, and Theodore Sider employs a similar argument not just for unrestricted composition but also for the doctrine of temporal parts. This sort of argument could be generalised, to produce a lot of other less palatable metaphysical conclusions. However, arguments to Lewis’s and Sider’s conclusions on the basis of considerations (...) about vagueness are uncompelling, even if we accept the crucial premises about vagueness. And a good thing too, since the generalised form of the argument would prove far too much. (shrink)

The thesis of 3D/4D equivalence states that every three-dimensional description of the world is translatable without remainder into a four-dimensional description, and vice versa. In representing an object in 3D or in 4D terms we are giving alternative descriptions of one and the same thing, and debates over whether the ontology of the physical world is "really" 3D or 4D are pointless. The twins paradox is shown to rest, in relativistic 4D geometry, on a reversed law of triangle inequality. But (...) considering the twins as 3D beings who age through time, the paradox implies that time passes at different rates in different reference frames, and therefore that the concept of a single global or Absolute time is unsustainable. (shrink)

Van Bendegem has recently offered an argument to the effect that, if time is discrete, then there should exist a correspondence between the motions of massive bodies and a discrete geometry. On this basis, he concludes that, even if space is continuous, it should nonetheless appear discrete. This paper examines the two possible ways of making sense of that correspondence, and shows that in neither case van Bendegem’s conclusion logically follows.

Theodore Sider’s Four-Dimensionalism is a well-organized and clearly written book that is chock-full of important arguments. Both friends and foes of the views defended by Sider will benefit enormously from careful study of the book. I am going to focus on just two of Sider’s many arguments for Four-Dimensionalism: his argument from vagueness, which I take to be the most important and powerful argument in the book, and his argument from time travel, which I find to be the funnest to (...) think about. (shrink)

In this essay for a PPR book symposium on Theodore Sider's _Four-Dimensionalism<D>, I focus on two of Sider's arguments for four-dimensionalism: (i) his argument from vagueness, and (ii) his argument from time travel. Concerning (i), I first show that Sider's argument commits him to certain strange consequences that many four-dimensionalists may not endorse, and then I discuss an objection that involves appealing to 'brutal composition', the view that there is no informative answer to Peter van Inwagen's 'special composition question'. Concerning (...) (ii), I argue that the three-dimensionalist can account for time travel scenarios in a way that is analogous to Sider's four-dimensionalist account of such scenarios. (shrink)

E. J. Lowe; The problems of intrinsic change: rejoinder to Lewis, Analysis, Volume 48, Issue 2, 1 March 1988, Pages 72–77, https://doi.org/10.1093/analys/48.2.7.

Are we the people we were? If we are continuants, then the answer to this question is an affirmative one. But it is a moot point whether anything is a continuant. The debate over this issue—of whether there are such things as continuants—is often conducted in the context of theories concerning the apparent passage of time. Thus it has been argued that the tenseless theory of time, according to which time does not really pass, forces us to tear down part (...) of the basis for the intuitive distinction between ordinary, reidentifiable objects on the one hand, and processes on the other, and to regard such objects as mountains as persisting through time in exactly the way that thunderstorms do: by having distinct temporal parts at different times. I confess that I am a tenseless theorist of time, and take that theory to entail such a conclusion about the persistence of objects. But it is not just a certain stance over time’s passage that motivates sympathy towards temporal parts and suspicion of continuants. Thinking of objects as having temporal parts sits more comfortably than does the rival view with two natural assumptions concerning continuity: that beginning and ceasing to exist, at least for most objects, involves underlying changes which are continuous in nature; and that objects exhibit continuity through time, in the sense of not having gaps in their existence. Or so I shall argue in what follows. (shrink)

In his excellent book, Four-Dimensionalism: An Ontology of Persistence and Time (Sider, 2001), Theodore Sider defends a version of four-dimensionalism which he calls the ‘stage-theory’. This paper focuses on Sider's argument from vagueness and argues that, due to the problematic nature of the argument from vagueness, Sider’s case in favor of four-dimensionalism is in the end not successful.

I offer a clear conception of a temporal part that does not make the existence of temporal parts implausible. This can be done if (and only if) we think of physical objects as four dimensional, The fourth dimension being time. Unless we are willing to deny the existence of most spatial parts, Or willing to accept the possibility of coincident entities, Or accept something even more implausible, We should accept the existence of temporal parts.

Katherine Hawley explores and compares three theories of persistence -- endurance, perdurance, and stage theories - investigating the ways in which they attempt to account for the world around us. Having provided valuable clarification of its two main rivals, she concludes by advocating stage theory.

At 8 a.m. I get in my car and set off for work. At 7:59 a.m., before I started it, my car was at rest; at 8:01 a.m. it is in motion. When a thing is not in motion, it is at rest, and when it is not at rest, it is in motion. But what was the state of the car at 8:00 a.m., as I was starting it? It would be inaccurate to say that it was in motion (...) but it would be inaccurate, also, to say that it was at rest: it was “just starting.” But, if whenever a thing is not in motion it is at rest, the state of “just starting”—or, of course, the comparable state of “just stopping”—must be either a state of motion or a state of rest. Which? (shrink)