Online research in philosophy

Under the eternalist hypothesis that objects or events exist temporally, but independently of being present two different views of persistence are on the market: Persisting objects endure if they are multiply located in (space-)time, and persisting objects perdure if they are singly located by having numerically different temporal parts. In the framework of the special theory of relativity (SR), the metaphysics of persistence is confronted with peculiar difficulties. Things persist by being “wholly present” at more than one time; but what are times within a temporally non-separated spacetime? Things persist by having different temporal parts at different times; but what are the temporal parts of a four-dimensional object in Minkowski spacetime? Recently, several authors have argued that SR favours perdurantism over its endurantist rival. In this paper, I intend to show that the purported arguments are only those against endurantism. The first simply fails, but the second, more convincing one, is such that with a similar strategy we should argue against perdurantism as well: Enduring and perduring entities are hence both in conflict with SR which undermines the eternalist hypothesis.

In response to a recent challenge that the New B-theory of Time argues invalidly from the claim that tensed sentences have tenseless truth conditions to the conclusion that temporal reality is tenseless, I argue that while early B-theorists may have relied on some such inference, New B-theorists do not. Giving tenseless truth conditions for tensed sentences is not intended to prove that temporal reality is tenseless. Rather, it is intended to undermine the A-theorist’s move from claims about the irreducibility of tensed language to the conclusion that temporal reality must be tensed. I then examine how A-theorists have used facts about language in attempting to establish their conclusions about the nature of temporal reality. I take the recent work of William Lane Craig and argue that he implicitly and illicitly moves from facts about temporal language to his conclusion that temporal reality is tensed.

Abstract: A theory of time is a theory of the nature of temporal reality, and temporal reality determines the truth-value of temporal sentences. Therefore it is reasonable to ask how a theory of time can account for the way the truth of temporal sentences is determined. This poses certain challenges for both the A theory and the B theory of time. In this paper, I outline an account of temporal sentences. The key feature of the account is that the primary bearers of truth-values are not utterances, but sentences evaluated with respect to a time. I argue that unlike other views, the present proposal can meet the challenges faced both by the A and the B theory.

In this paper I argue that a recently discovered set of visual illusions sheds new light on the nature of time consciousness. In particular, I argue that these illusions put strong pressure on a view I call Temporal Atomism that otherwise might have seemed quite attractive. According to temporal atomism if you were to fix which non-temporal properties are experienced as well as the temporal properties of your experience itself, you would also have fixed which temporal properties are experienced. While it has been claimed before that views like temporal atomism are confused, and face conceptual as well as empirical problems, my argument based on the newly discovered illusions provides a new and more straightforward challenge: temporal atomism either has to give up its crucial motivations, or it can not even so much as make sense of the content of the subject’s visual experience. I end with brief suggestions concerning how the results of this paper bears on further philosophical debates about time consciousness, change blindness, and the role of attention in perceptual experience.

I first distinguish several notions that have traditionally been conflated (or otherwise neglected) in discussions of the metaphysics of time. Thus, for example, I distinguish between the passage of time and temporal becoming. The former is, I maintain, a confused notion that does not represent a feature of the world; whereas a proper understanding of the latter provides the key for a plausible and comprehensive account of the nature of temporal reality. There are two general classes of views of the nature of temporal reality; proponents of particular views in both classes attempt to account for the phenomenon of temporal becoming in terms of qualitative change. I argue that any such account – in terms of change – is irredeemably problematic. And so I propound a different account of temporal becoming, based on the notion that temporal reality is transient, which provides the means to characterize intuitively and vividly the significant effects of time on the metaphysical nature of the world.

If ordinary objects have temporal parts, then temporal predications have the following truth conditions: necessarily, ( a is F) at t iff a has a temporal part that is located at t and that is F. If ordinary objects have temporal counterparts, then, necessarily, ( a is F) at t iff a has a temporal counterpart that is located at t and that is F. The temporal-parts account allows temporal predication to be closed under the parthood relation: since all that is required to be F at t is to have a temporal part, a t , that is located at t and that is F, every object that has a t as a temporal part is F at t . Similarly for the temporal-counterparts account. Both closure under parthood and closure under counterparthood are shown to have unacceptable consequences. Then strategies for avoiding closure are considered and rejected.

Those who believe that ordinary things have temporal as well as spatial parts must give an account of the truth conditions of temporally modified predications of the form ‘a is F at t ’ in terms of temporal parts. I will argue that the friend of temporal parts is committed to an account of temporal predication that is incompatible with the classical principle of predicate abstraction.

The following quotation, from Frank Jackson, is the beginning of a typical exposition of the debate between those metaphysicians who believe in temporal parts, and those who do not: The dispute between three-dimensionalism and four-dimensionalism, or more precisely, that part of the dispute we will be concerned with, concerns what persistence, and correllatively, what change, comes to. Three-dimensionalism holds that an object exists at a time by being wholly present at that time, and, accordingly, that it persists if it is wholly present at more than one time. For short, it persists by enduring. Four-dimensionalism holds that an object exists at a time by having a temporal part at that time, and it persists if it has distinct temporal parts at more than one time. For short, it persists by perduring (Jackson 1998, p. 138). In the light of these comments, some readers will perhaps find the question that forms the title of this paper a little puzzling. They may have learned to use the terms ‘fourdimensionalism’ ‘perdurantism’ and ‘belief in temporal parts’ interchangeably; or perhaps even to define one in terms of the other. Such a usage, however, is inapposite. We might imagine a Flatland-like world of two spatial dimensions and one temporal, whose philosophers are divided between a theory of persistence on which they persist by having temporal parts, and a theory on which they persist by being wholly located in each of several times. This is just the same issue we face, but at least the label ‘four-dimensionalism’ seems inapposite: the four-dimensionalist Flatlanders believe in only three dimensions!

Philosophers have long struggled to understand our perceptual experience of temporal properties such as succession, persistence and change. Indeed, strikingly, a number have felt compelled to deny that we enjoy such experience. Philosophical puzzlement arises as a consequence of assuming that, if one experiences succession or temporal structure at all, then one experiences it at a moment. The two leading types of theory of temporal awareness—specious present theories and memory theories—are best understood as attempts to explain how temporal awareness is possible within the constraints of this principle. I argue that the principle is false. Neither theory of temporal awareness can be made workable unless it is rejected. Our experience of temporal phenomena cannot be understood if we attempt to break experience down into instantaneous slices. In order to understand the perception of temporal properties we must look beyond the instant.

This thesis is about the conceptualization of persistence of physical, middle-sized objects within the theoretical framework of the revisionary ‘B-theory’ of time. According to the B-theory, time does not flow, but is an extended and inherently directed fourth dimension along which the history of the universe is ‘laid out’ once and for all. It is a widespread view among philosophers that if we accept the B-theory, the commonsensical ‘endurance theory’ of persistence will have to be rejected. The endurance theory says that objects persist through time by being wholly present at distinct times as numerically the same entity. Instead of endurantism, it has been argued, we have to adopt either ‘perdurantism’ or the ‘stage theory’. Perdurantism is the theory that objects are four-dimensional ‘space-time worms’ persisting through time by having distinct temporal parts at distinct times. The stage theory says that objects are instantaneous temporal parts (stages) of space-time worms, persisting by having distinct temporal counterparts at distinct times. In the thesis, it is argued that no good arguments have been provided for the conclusion that we are obliged to drop the endurance theory by acceptance of the B-theory. This conclusion stands even if the endurance theory incorporates the claim that objects endure through intrinsic change. It is also shown that perdurantism and the stage theory come with unwelcome consequences. Paper I demonstrates that the main arguments for the view that objects cannot endure in B-time intrinsically unchanged fail. Papers II and III do the same with respect to the traditional arguments against endurance through intrinsic change in B-time. Paper III also contains a detailed account of the semantics of the tenseless copula, which occurs frequently in the debate. The contention of Paper IV is that four-dimensional space-time worms, as traditionally understood, are not suited to take dispositional predicates. In Paper V, it is shown that the stage theory needs to introduce an overabundance of persistence-concepts, many of which will have to be simultaneously applicable to a single object (qua falling under a single sortal), in order for the theory to be consistent. The final article, Paper VI, investigates the sense in which persistence can, as is sometimes suggested, be a ‘conventional matter’. It also asks whether alleged cases of ‘conventional persistence’ create trouble for the endurance theory. It is argued that conventions can only enter at a trivial semantic level, and that the endurance theory is no more threatened by such conventions than are its rivals.