I offer an argument in defense of four-dimensionalism, the view that objects are temporally, as well as spatially extended. The argument is of the inference-to-the-best-explanation variety and is based on relativistic considerations. It deals with the situation in which one and the same object has different three-dimensional shapes at the same time and proceeds by asking what sort of thing it must be in order to present itself in such different ways in various "perspectives" (associated with moving reference frames) without (...) being different from itself. I argue that the best answer is that the object must be four-dimensional. It will then have differing 3D shapes in different perspectives because such shapes are intrinsic properties of its 3D parts. (shrink)

I examine the issue of persistence over time in thecontext of the special theory of relativity (SR). Thefour-dimensional ontology of perduring objects isclearly favored by SR. But it is a different questionif and to what extent this ontology is required, andthe rival endurantist ontology ruled out, by thistheory. In addressing this question, I take theessential idea of endurantism, that objects are whollypresent at single moments of time, and argue that itcommits one to unacceptable conclusions regardingcoexistence, in the context of SR. (...) I then propose anddiscuss a plausible account of coexistence forperduring objects, which is free of these defects. This leaves the endurantist room for some maneuvers. I consider them and show that they do not really helpthe endurantist out. She can accommodate the notionof coexistence in the relativistic framework only atthe cost of renouncing central endurantist intuitions. (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.

∗ Apologies to Mark Hinchliff for stealing the title of his dissertation. (See Hinchliff, A Defense of Presentism. As it turns out, however, the version of Presentism defended here is different from the version defended by Hinchliff. See Section 3.1 below.).

Step by step the reader is introduced, through analysis of the fundamental problems of Being, the relation of thoughts to things, novelty, causation, and the ...

Challenging, with several powerful arguments, some of our deepest beliefs about rationality, morality, and personal identity, Parfit claims that we have a false view about our own nature. It is often rational to act against our own best interersts, he argues, and most of us have moral views that are self-defeating. We often act wrongly, although we know there will be no one with serious grounds for complaint, and when we consider future generations it is very hard to avoid conclusions (...) that most of us will find very disturbing. (shrink)

_Time_'s 'Man of the Century', Albert Einstein is the unquestioned founder of modern physics. His theory of relativity is the most important scientific idea of the modern era. In this short book Einstein explains, using the minimum of mathematical terms, the basic ideas and principles of the theory which has shaped the world we live in today. Unsurpassed by any subsequent books on relativity, this remains the most popular and useful exposition of Einstein's immense contribution to human knowledge.

Quentin Smith offers powerful arguments against the New Theory of Reference propounded by leading thhinkers in the philosophy of language. Smith defends the tensed theory of time and argues that the simultaneity is absoltue, basing this position on the theory that all propositions exist in time. Using detailed propostitions and a theory of cognitive significance, he introduces an alternative interpretation of reference that will be relevant to metaphysicians, philosophers of science and philosophers of language and may come to be recognised (...) as the definitive statement on the tensed theory of time. (shrink)

Disposition ascription has been discussed a good deal over the last few decades, as has the revisionary metaphysical view of ordinary, persisting objects known as 'fourdimensionalism'. However, philosophers have not merged these topics and asked whether four-dimensional objects can be proper subjects of dispositional predicates. This paper seeks to remedy this oversight. It argues that, by and large, four-dimensional objects are not suited to take dispositional predicates.

PHYSICAL MEANING OF GEOMETRICAL PROPOSITIONS IN your schooldays most of you who read this book made acquaintance with the noble building of Euclid's ...

It is known that Maxwell’s electrodynamics—as usually understood at the present time—when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies (...) is in motion. For if the magnet is in motion and the conductor at rest, there arises in the neighbourhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet. In the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy, but which gives rise—assuming equality of relative motion in the two cases discussed—to electric currents of the same path and intensity as those produced by the electric forces in the former case. Examples of this sort, together with the unsuccessful attempts to discover any motion of the earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good.1 We will raise this conjecture (the purport of which will hereafter be called the “Principle of Relativity”) to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.. (shrink)

This is the text of The Lindley Lecture for 1962, given by Arthur N. Prior (1914-1969).

This book offers a defense of the tensed theory of time, a critique of the New Theory of Reference, and an argument that simultaneity is absolute. Although Smith rejects ordinary language philosophy, he shows how it is possible to argue from the nature of language to the nature of reality. Specifically, he argues that semantic properties of tensed sentences are best explained by the hypothesis that they ascribe to events temporal properties of futurity, presentness, or pastness and do not merely (...) ascribe relations of earlier than or simultaneity. He criticizes the New Theory of Reference, which holds that "now" refers directly to a time and does not ascribe the property of presentness. Smith does not adopt the old or Fregean theory of reference but develops a third alternative, based on his detailed theory of de re and de dicto propositions and a theory of cognitive significance. He concludes the book with a lengthy critique of Einstein's theory of time. Smith offers a positive argument for absolute simultaneity based on his theory that all propositions exist in time. He shows how Einstein's relativist temporal concepts are reducible to a conjunction of absolutist temporal concepts and relativist nontemporal concepts of the observable behavior of light rays, rigid bodies, and the like. (shrink)

Standard lore has it that a proper name is a temporally rigid designator. It picks out the same entity at every time at which it picks out an entity at all. If the entity in question is an enduring continuant then we know what this means, though we are also stuck with a host of metaphysical puzzles concerning endurance itself. If the entity in question is a perdurant then the rigidity claim is trivial, though one is left wondering how it (...) is that different speakers ever manage to pick out one and the same entity when a host of suitable, overlapping candidates are available. But what if the entity in question is neither a continuant nor a perdurant? What if the things we talk about in ordinary language are time-bound entities that cannot truly be said to persist through time, or stage sequences whose unity resides exclusively in our minds--like the “waves” at the stadium or the characters of a cartoon? In such cases the rigidity claim can’t be right and a counterpart-theoretic semantics seems required. Is that bad? I say it isn’t. And it had better not be, if that turns out to be the best metaphysical option we have. (shrink)

Standard lore has it that a proper name, or a definite description on its de re reading, is a temporally rigid designator. It picks out the same entity at every time at which it picks out an entity at all. If the entity in question is an enduring continuant then we know what this means, though we are also stuck with a host of metaphysical puzzles concerning endurance itself. If the entity in question is a perdurant then the rigidity claim (...) is trivial, though one is left wondering how it is that different speakers ever manage to pick out one and the same entity when a host of suitable, overlapping candidates are available. But what if the entity in question is neither a continuant nor a perdurant? What if the things we talk about in ordinary language are time‐bound entities that cannot truly be said to persist through time, or stage sequences whose unity resides exclusively in our minds ‐ like the “wave” at the stadium or the characters of a cartoon? In such cases the rigidi‐ ty claim can't be right and a counterpart‐theoretic semantics seems required. Is that bad? I say it isn't. And it had better not be, if that turns out to be the best metaphysical option we have. (shrink)

Although the relationship of part to whole is one of the most fundamental there is, this is the first full-length study of this key concept. Showing that mereology, or the formal theory of part and whole, is essential to ontology, Simons surveys and critiques previous theories--especially the standard extensional view--and proposes a new account that encompasses both temporal and modal considerations. Simons's revised theory not only allows him to offer fresh solutions to long-standing problems, but also has far-reaching consequences for (...) our understanding of a host of classical philosophical concepts. (shrink)

Eternalists say that non-present entities (for instance dinosaurs) exist; presentists say that they do not. But some sceptics deny that this debate is genuine, claiming that presentists simply represent eternalists' quantifiers over non-present entities in different notation. This scepticism may be refuted on purely logical grounds: one of the leading candidate ‘presentist quantifiers’ over non-present things has the inferential role of a quantifier. The dispute over whether non-present objects exist is as genuine and non-verbal as the dispute over whether there (...) is life on other planets. (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)

Some philosophers believe that everyday objects are 4-dimensional spacetime worms, that a person (for example) persists through time by having temporal parts, or stages, at each moment of her existence. None of these stages is identical to the person herself; rather, she is the aggregate of all her temporal parts.1 Others accept “three dimensionalism”, rejecting stages in favor of the notion that persons “endure”, or are “wholly present” throughout their lives.2 I aim to defend an apparently radical third view: not (...) only do I accept person stages; I claim that we are stages.3 Likewise for other objects of our everyday ontology: statues are statue-stages, coins are coin-stages, etc. At one level, I accept the ontology of the worm view. I believe in spacetime worms, since I believe in temporal parts and aggregates of things I believe in. I.. (shrink)

This paper argues against the common practice of presenting perdurantism, endurantism, and other views about persistence and time as solutions to an alleged puzzle about change. Various recent attempts to generate a puzzle about change are examined and found unsuccessful. This does not mean, however, that the relevant views about persistence and time are not well motivated, but rather that their interest and purpose is independent of their suitability for solving the alleged puzzle.

According to four dimensionalism, the material world is divided into momentary stages. In a four-dimensional world, which objects are the ordinary things, the things we normally name and quantify over? Aggregates of stages, according to most four-dimensionalists, but according to stage theorists (or exdurantists), ordinary objects are instead to be identified with the stages themselves. (A temporal counterpart theoretic account of de re temporal predication is then given.) This paper argues that a stage theorist is best positioned to accept David (...) Lewis's argument from temporary intrinsics for four-dimensionalism, since stage theorists are the only four-dimensionalists who attribute monadic temporary intrinsic properties to ordinary things. (shrink)

Objects and Persons presents an original theory about what kinds of things exist. Trenton Merricks argues that there are no non-living inanimate macrophysical objects -- no statues or rocks or chairs or stars -- because they would have no causal role over and above the causal role of their microphysical parts. Humans do exist: we have non-redundant causal powers. Along the way, Merricks has interesting things to say about mental causation, free will, and various philosophical puzzles. Anyone working in metaphysics (...) will enjoy this lucid and provocative book. (shrink)