It is often said that the world is explained by laws of nature together with initial conditions. But does that mean initial conditions don’t require further explanation? And does the explanatory role played by initial conditions entail or require that time has a preferred direction? This chapter looks at the use of the ‘initialness defence’ in physics, the idea that initial conditions are intrinsically special in that they don’t require further explanation, unlike the state of the world at other times. (...) Such defences commonly assume a primitive directionality of time to distinguish between initial and final conditions. Using the case study of the time-asymmetry of thermodynamics and the so-called ‘past hypothesis’ — the hypothesis that the early universe was in a state of very low entropy —, I outline and support a deflationary account of the initialness defence that does not pre- suppose a basic directionality of time, and argue that there is a relevant explanatory asymmetry between initial conditions and the state of systems at other times only if certain causal conditions are satisfied. Hence, the initialness defence is available to those who reject a fundamental direction of time. (shrink)

We explore the role of episodic imagining in explaining why people both differentially report that it seems to them in experience as though time robustly passes, and why they differentially report that they believe that time does in fact robustly pass. We empirically investigate two hypotheses, the differential vividness hypothesis, and the mental time travel hypothesis. According to each of these, the degree to which people vividly episodically imagine past/future states of affairs influences their tendency to report that it seems (...) to them as though time robustly passes and to judge that time does robustly pass. According to the former, a greater degree of vividness will tend to increase the extent to which people make such reports, while according to the latter, it will tend to decrease the extent to which people make such reports. We found weak evidence in favour of the former hypothesis. We reflect on the implications of this finding for theorising about such reports. (shrink)

Modern physics has provided a range of motivations for holding time to be fundamentally undirected. But how does a temporally adirectional metaphysics, or ‘C-theory’ of time, fit with the time of experience? In this chapter, I look at what kind of problem human time poses for C-theories. First, I ask whether there is a ‘hard problem’ of human time: whether it is in principle impossible to have the kinds of experience we do in a temporally adirectional world. Second I consider (...) the ‘easy problem’: how specific directed aspects of our temporal experience are to be explained by C-theorists. This leads to a greater issue: is there such a thing as an experience of time direction at all to even be explained? I show how the kinds of experience we have that we typically associate with the idea of time being directed can be accommodated within a directionless picture of time. (shrink)

This book defends a relational theory of the passage of time. The realist view of passage developed in this book differs from the robust, substantivalist position. According to relationism, passage is nothing over and above the succession of events, one thing coming after another. Causally related events are temporally arranged as they happen one after another along observers’ worldlines. There is no unique global passage but a multiplicity of local passages of time. After setting out this positive argument for relationism, (...) the author deals with five common objections to it: (a) triviality of deflationary passage, (b) a-directionality of passage, (c) the impossibility of experiencing passage, (d) fictionalism about passage, and (e) the incompatibility of passage with perduring objects. (shrink)

We regularly talk of the experience of time passing. Some theorists have taken the supposed phenomenology of time passing to provide support for metaphysical accounts of the nature of time; opposing theorists typically granted that there is a phenomenology of time passing while seeking to dispute that any metaphysical conclusions about time can be drawn from this. In recent debates theorists have also begun to dispute that there is a phenomenology of time passing – plausibly, if there is not, then (...) there is no relevant experience to be explained away, or for metaphysical conclusions to be drawn from. In the present paper I offer one explanation of why such disputes about the experience of time passing may seem intractable. However, I suggest that there is a distinct and more tractable issue lurking in this area, concerning our experience of how certain phenomena persist over time. Interestingly, articulating how we experience different phenomena as persisting over time doesn't simply provide a challenge to one metaphysical view of persistence rather than another; instead, it generates an explanatory challenge for a variety of competing views of persistence and, by extension, a challenge for popular combinations of views of the metaphysics of persistence and of time. (shrink)

This article brings time and theology together constructively in response to a pressing problem for the doctrine of personal salvation. The problem arises within the physics and metaphysics of time, as these support a so-called temporal B-theory in which time does not pass and reality is comprised of a block universe. Within this static temporal metaphysic, objective change is highly problematized. Yet salvation requires an objective change from fallenness to redemption. So, how can we understand a salvation-transformation in the block (...) universe? In other words, can sinners really change? I argue that on a B-theory of time, a salvation-transformation is best understood as a form of qualitative, phenomenological, and subjective change, rather than a robust ontological change. I conclude that the individual's transformation from fallen to saved is one of mind-dependent becoming. So, sinners can change. But, in this lifetime, that change can only be subjective. (shrink)

Appeals to the ‘common sense’, or ‘naïve’, or ‘folk’ concept of time, and the purported phenomenology as of time passing, play a substantial role in philosophical theorising about time. When making these appeals, philosophers have been content to draw upon their own assumptions about how non-philosophers think about time. This paper reviews a series of recent experiments bringing these assumptions into question. The results suggest that the way non-philosophers think about time is far less metaphysically demanding than philosophers have assumed.

McTaggart’s paradox and his A-theory and B-theory are basic notions in the contemporary philosophy of time. It is well known that the paradox was introduced by McTaggart’s paper called “The Unreality of Time” published in 1908, so that it has a one-hundred-year history. As for A-theory and B-theory, in contrast, McTaggart himself didn’t consider both of them at all. The notions of A-theory and B-theory came much later, 60 years after the paradox. Moreover, they had not been as popularized as (...) they are today until quite recently, at least after the 1990s. This paper aims to trace the origin of the notions of A-theory and B-theory and show how the debates behind them, especially objections to “spatialising time,” form the notions. (shrink)

Presentism is, roughly, the ontological view that only the present exists. Among the philosophers engaged in the metaphysics of time there is wide agreement that presentism is intuitive (or commonsensical) and that its intuitiveness counts as evidence in its favour. My contribution has two purposes: first, defending the view that presentism is intuitive from some recent criticisms; second, putting forth a genealogical (or debunking) argument aimed at depriving presentism’s intuitiveness of the evidential value commonly granted to it.

Temporal ontology is the philosophical debate on the existence of the past and the future. It features a three-way confrontation between supporters of presentism (the present exists, the past and the future do not), pastism (the past and the present exist, the future does not), and eternalism (the past, the present, and the future all exist). Most philosophers engaged in this debate believe that presentism is much more in agreement with common sense than the rival views; moreover, most of them (...) believe that being in agreement with common sense is epistemically valuable for a philosophical view. We studied experimentally non-experts’ ideas pertaining to the domain of temporal ontology, i.e., as we called it, common-sense temporal ontology, focusing on the Italian population. We found that a non-overwhelming majority of participants (~64%) favoured presentism, while two significant minorities favoured pastism (~19%) and eternalism (~17%). We think that our findings provide some support, albeit weaker than expected, for the view that presentism is more in agreement with common sense than the rival positions. (shrink)

In what sense is the direction of time a matter of convention? In 'The Direction of Time', Hans Reichenbach makes brief reference to parallels between his views about the status of time’s direction and his conventionalism about geometry. In this article, I: (1) provide a conventionalist account of time direction motivated by a number of Reichenbach’s claims in the book; (2) show how forwards and backwards time can give equivalent descriptions of the world despite the former being the ‘natural’ direction (...) of time; and (3) argue that this offers an important middle-ground position between existing realist and antirealist accounts of the direction of time. (shrink)

This paper aims to determine whether we can locate temporal passage in a non-dynamical (block universe) world. In particular, we seek to determine both whether temporal passage can be located somewhere in our world if it is non-dynamical, and also to home in on where in such a world temporal passage can be located, if it can be located anywhere. We investigate this question by seeking to determine, across three experiments, whether the folk concept of temporal passage can be satisfied (...) in our world if it is non-dynamical, and, if it can, what sort of thing in our world satisfies that concept. In particular, we focus on the question of whether that concept (if satisfied) is satisfied by something mind-dependent or something mind-independent. In other words, we ask, is temporal passage something that is at least partially in the mind, or is it entirely external to the mind? We find, contrary to what is often assumed by dynamists and non-dynamists alike, that the folk concept of temporal passage is satisfied in our world conditional on it being non-dynamical, and that the concept is satisfied by something mind-independent. This provides further ammunition for recent deflationary accounts of temporal passage that attempt to locate passage somewhere in our non-dynamical world. (shrink)

In this paper, we put forward an alternative interpretation of time-reversal symmetry in philosophy of physics: Humean time-reversal symmetry. According to it, time-reversal symmetry is understood as a heuristic, epistemic virtue of the best system, not as a property of the Humean mosaic. One of the consequences of this view is that one of the main arguments against a primitive direction of time is rendered harmless, which paves the way for primitivism about the direction of time.

The A-theory of time is plagued by certain standard armchair problems: the presentism–eternalism dilemma, the problem of truth-makers, the alleged impossibility of cross-temporal relations, and the problem of temporary intrinsics. These challenges supposedly force A-theories to make incredible claims. I argue that these challenges are not deep antinomies in common sense, but rest on avoidable mistakes. Then I present a new A-theory that shows what’s possible once we move past the old problems. On this proposal, time’s passing is a metaphysically (...) fundamental aspect of reality. I take this to mean that there are fundamental facts like: four hours passed from 8am today until noon. This A-theory also posits fundamental facts about the state of the universe at a time, and about cross-temporal relationships. The proposed metaphysical package attractively articulates our common sense, pre-relativistic conception of time. (shrink)

We conduct a case study analysis of a proposal for the emergence of time based upon the approximate derivation of three grades of temporal structure within an explicit quantum cosmological model which obeys a Wheeler-DeWitt type equation without an extrinsic time parameter. Our main focus will be issues regarding the consistency of the approximations and derivations in question. Our conclusion is that the model provides a self-consistent account of the emergence of chronordinal, chronometric and chronodirected structure. Residual concerns relate to (...) explanatory rather than consistency considerations. (shrink)

This dissertation is concerned with two of the largest questions that we can ask about the nature of physical reality: first, whether physical reality begin to exist and, second, what criteria would physical reality have to fulfill in order to have had a beginning? Philosophers of religion and theologians have previously addressed whether physical reality began to exist in the context of defending the Kal{\'a}m Cosmological Argument (KCA) for theism, that is, (P1) everything that begins to exist has a cause (...) for its beginning to exist, (P2) physical reality began to exist, and, therefore, (C) physical reality has a cause for its beginning to exist. While the KCA has traditionally been used to argue for God's existence, the KCA does not mention God, has been rejected by historically significant Christian theologians such as Thomas Aquinas, and raises perennial philosophical questions -- about the nature and history of physical reality, the nature of time, the nature of causation, and so on -- that should be of interest to all philosophers and, perhaps, all humans. While I am not a religious person, I am interested in the questions raised by the KCA. In this dissertation, I articulate three necessary conditions that physical reality would need to fulfill in order to have had a beginning and argue that, given the current state of philosophical and scientific inquiry, we cannot determine whether physical reality began to exist. -/- Friends of the KCA have sought to defend their view that physical reality began to exist in two distinct ways. As I discuss in chapter 2, the first way in which friends of the KCA have sought to defend their view that physical reality began to exist involves a family of a priori arguments meant to show that, as a matter of metaphysical necessity, the past must be finite. If the past is necessarily finite, then the past history of physical reality is necessarily finite. And if having a finite past suffices for having a beginning, then, since the past history of physical reality is necessarily finite, physical reality necessarily began to exist. I show that the arguments which have been offered thus far for the view that the past is necessarily finite do not succeed. Moreover, as I elaborate on in chapter 5, having a finite past does not suffice for having a beginning. -/- As I discuss in chapter 3, the second way in which friends of the KCA have sought to defend their view that physical reality began to exist involves a family of a posteriori arguments meant to show that we have empirical evidence that physical reality has a finite past history. For example, the big bang is sometimes claimed to have been the beginning of physical reality and, since we have excellent empirical evidence for the big bang, we have excellent empirical evidence for the beginning of physical reality. The big bang can be understood in two ways. On the one hand, the big bang can be understood as a theory about the history and development of the observable universe. Understood in that sense, then I agree that the big bang is supported by excellent empirical evidence and by a scientific consensus. On the other hand, some authors (particularly science popularizers, science journalists, and religious apologists) have wrongly interpreted big bang theory as a theory about the beginning of the whole of physical reality. As I argue, while a beginning of physical reality may be consistent with classical big bang theory, classical big bang theory does not provide good reason for thinking that physical reality began to exist. -/- In part II, I turn to discussing three necessary, but not necessarily sufficient, conditions for physical reality to have a beginning. Before discussing the three conditions, in chapter 4, I introduce three metaphysical accounts of the nature of time (A-theory, B-theory, and C-theory) as well as some formal machinery that will subsequently become useful in the dissertation. I introduce the first of the three conditions in chapter 5. According to the Modal Condition, physical reality began to exist only if, at the closest possible worlds without time, physical reality does not exist. I show that this condition helps us to make sense of various views in both theology and philosophy of physics. In chapter 6}, I introduce the second of my three conditions, the Direction Condition, according to which, roughly, physical reality began to exist only if all space-time points agree about the direction of time, so that all space-time points can agree that physical reality's putative beginning took place in their objective past. In chapter 7, I discuss the third condition, the Boundary Condition, according to which physical reality began to exist only if there is a past temporal boundary such that physical reality did not exist before the boundary. I show that there are two senses in which physical reality could be said to have had a past temporal boundary. Lastly, in chapter 8, I show that there is a relationship between my three conditions and classical big bang theory, even though the relationship is not the one usually identified in the literature. -/- In part III, I present four arguments for the view that, at the present stage of philosophical and scientific inquiry, we cannot know whether physical reality satisfies the three necessary conditions to have had a beginning and, consequently, we cannot know whether physical reality had a beginning. As I will prove in chapter 9, no set of observations that we currently have, when conjoined with General Relativity, entails that physical reality satisfies the Direction or Boundary Conditions. As I show in chapter 10, considerations in the philosophical foundations of statistical mechanics entail either that the Cosmos violates the Modal Condition or else that there is a transcendental condition on the possibility of our knowledge of the past that prevents our access to data we would need to gather to determine whether physical reality satisfies the Boundary Condition. In chapter 11, I show that there are a number of live cosmological models according to which physical reality does not satisfy the Boundary Condition. As long as we don't know whether any of those cosmological models are correct, we do not know whether physical reality satisfies the Boundary Condition. Lastly, I turn to confirmation theory and show that, at our present stage of inquiry, ampliative inferences for the conclusion that physical reality satisfies the Modal, Direction, and Boundary Conditions are not successful. (shrink)