The paper analyzes the philosophical consequences of the recent discovery of direct violations of the time–reversal symmetry of weak interactions. It shows that although we have here an important case of the time asymmetry of one of the fundamental physical forces which could have had a great impact on the form of our world with an excess of matter over antimatter, this asymmetry cannot be treated as the asymmetry of time itself but rather as (...) an asymmetry of some specific physical process in time. The paper also analyzes the consequences of the new discovery for the general problem of the possible connections between direction of time and time-asymmetric laws of nature. These problems are analyzed in the context of Horwich’s Asymmetries in time: problems in the philosophy of science argumentation, trying to show that existence of a time–asymmetric law of nature is a sufficient condition for time to be anisotropic. Instead of Horwich’s sufficient condition for anisotropy of time, it is stressed that for a theory of asymmetry of time to be acceptable it should explain all fundamental time asymmetries: the asymmetry of traces, the asymmetry of causation, and the asymmetry between the fixed past and open future. It is so because the problem of the direction of time has originated from our attempts to understand these asymmetries and every plausible theory of the direction of time should explain them. (shrink)

An important aspect of the debate between the A-theory and the B-theory of time relates to the supposed implications of each for some of the most basic human attitudes and stances. The asymmetry in our attitudes towards past and future events in our life (pleasant and unpleasant), and towards the temporal limits of our existence, that is, toward birth and death, is supposedly considered differently by the two theories. I argue that our attitudes are neither justified nor discredited (...) by anything which is in debate between the A-Theory and the B-theory, and therefore that neither theory of time is supported by the asymmetry in our attitudes. (shrink)

The physics of time asymmetry has never been a single well-defined subject, but more a collection of consistency problems which arise in almost all branches ...

We consider the mind-dependence or independence of the "now," of "becoming," and of "time's arrow," by considering the various senses in which these notions might be mind-dependent or not. These matters cannot be sensibly discussed without taking a stand regarding criteria of "reality." Proceeding from a basically phenomenalist position we conclude that merely to differentiate between appearance and reality is implicitly to assume a directed flow of time. We discuss the relationship between phenomenological and physical time and (...) their possible asymmetries. We find that physical time acquires meaning only through phenomenological time, and that phenomenological time is fundamentally asymmetric. This still leaves room for the question: Is there anything in physical time which reflects the fact that it, to be meaningful, must be applied asymmetrically? The relevance of relativity theory to this question is discussed. (shrink)

Time is generally thought to be one of the more mysterious ingredients of the universe. In this intriguing book, Paul Horwich makes precise and explicit the interrelationships between time and a large number of philosophically important notions.Ideas of temporal order and priority interact in subtle and convoluted ways with the deepest elements in our network of basic concepts. Confronting this conceptual jigsaw puzzle, Horwich notes that there are glaring differences in how we regard the past and future directions (...) of time. For example, we can influence the future but not the past, and can easily gain knowledge of the past but not of the future. Moreover we see a profusion of decay processes but little spontaneous generation of order; time appears to "flow" in one privileged direction, not the other; and we tend to explain phenomena in terms of antecedent circumstances, rather than subsequent ones. Horwich explains such time asymmetries and examines their bearing on the nature of time itself.Asymmetries in Time covers many notoriously difficult problems in the philosophy of science: causation, knowledge, entropy, explanation, time travel, rational choice, laws of nature, and counterfactual implication -- and gives a unified treatment of these matters. The book covers an unusually broad range of topics in a lucid and nontechnical way and includes alternative points of view in the philosophical literature. (shrink)

I discuss the nature of the puzzle about the time‐asymmetry of radiation and argue that its most common formulation is flawed. As a result, many proposed solutions fail to solve the real problem. I discuss a recent proposal of Mathias Frisch as an example of the tendency to address the wrong problem. I go on to suggest that the asymmetry of radiation, like the asymmetry of thermodynamics, results from the initial state of the universe.

This paper investigates what the source of time-asymmetry is in thermodynamics, and comments on the question whether a time-symmetric formulation of the Second Law is possible.

In several previous papers we have argued for a global and non-entropic approach to the problem of the arrow of time, according to which the “arrow” is only a metaphorical way of expressing the geometrical time-asymmetry of the universe. We have also shown that, under definite conditions, this global time-asymmetry can be transferred to local contexts as an energy flow that points to the same temporal direction all over the spacetime. The aim of this paper (...) is to complete the global and non-entropic program by showing that our approach is able to account for irreversible local phenomena, which have been traditionally considered as the physical origin of the arrow of time. (shrink)

In this survey, we discuss and analyze foundational issues of the problem of time and its asymmetry from a unified standpoint. Our aim is to discuss concisely the current theories and underlying notions, including interdisciplinary aspects, such as the role of time and temporality in quantum and statistical physics, biology, and cosmology. We compare some sophisticated ideas and approaches for the treatment of the problem of time and its asymmetry by thoroughly considering various aspects of (...) the second law of thermodynamics, nonequilibrium entropy, entropy production, and irreversibility. The concept of irreversibility is discussed carefully and reanalyzed in this connection to clarify the concept of entropy production, which is a marked characteristic of irreversibility. The role of boundary conditions in the distinction between past and future is discussed with attention in this context. The paper also includes a synthesis of past and present research and a survey of methodology. It also analyzes some open questions in the field from a critical perspective. (shrink)

One of the most striking features of causation is that causes typically precede their effects – the causal arrow is strongly aligned with the temporal arrow. Why should this be so? We offer an opinionated guide to this problem, and to the solutions currently on offer. We conclude that the most promising strategy is to begin with the de facto asymmetry of human deliberation, characterised in epistemic terms, and to build out from there. More than any rival, this subjectivist (...) approach promises to demystify the asymmetry, temporal orientation, and deliberative relevance of causal judgements. (shrink)

Huw Price argues that there are two conceptions of the puzzle of the time‐asymmetry of thermodynamics. He thinks this puzzle has remained unsolved for so long partly due to a misunderstanding about which of these conceptions is the right one and what form a solution ought to take. I argue that it is Price's understanding of the problem which is mistaken. Further, it is on the basis of this and other misunderstandings that he disparages a type of account (...) which does, in fact, hold promise of a solution. (shrink)

This paper argues that the knowledge asymmetry (the fact that we know more about the past than the future) can be explained as a consequence of the causal Markov condition. The causal Markov condition implies that causes of a common effect are generally statistically independent, whereas effects of a common cause are generally correlated. I show that together with certain facts about the physics of our world, the statistical independence of causes severely limits our ability to predict the future, (...) whereas correlations between joint effects make it so that no such limitation holds in the reverse temporal direction. Insofar as the fact that our world conforms to the causal Markov condition can itself be explained in terms of the initial conditions of the universe, my view is compatible with Albert’s well-known account of the origins of temporal asymmetries, but also provides a more illuminating way to derive the knowledge asymmetry from those initial conditions. (shrink)

Every process studied in any science other than physics defines an arrow of time – to say nothing for the directedness of the processes of causation, inference, memory, control, and counterfactual dependence that occur in everyday life. The discussion in this chapter is confined to the arrow of time as it occurs in physics. The chapter briefly discusses those features of microscopic physics, which seem to conflict with time asymmetry. It explains just how this conflict plays (...) out in the important context of thermodynamics and statistical mechanics. The chapter then reviews the main strategies available for resolving the conflict between reversible microdynamics and irreversible macrodynamics, working within the context of the quantitative, time‐irreversible evolution laws that seem to apply to large‐scale phenomena. Finally, it offers a broad the discussion covering other arrows of time within physics. (shrink)

Causes always seem to come prior to their effects. What might explain this asymmetry? Causation's temporal asymmetry isn't straightforwardly due to a temporal asymmetry in the laws of nature—the laws are, by and large, temporally symmetric. Nor does the asymmetry appear due to an asymmetry in time itself. This Element examines recent empirical attempts to explain the temporal asymmetry of causation: statistical mechanical accounts, agency accounts and fork asymmetry accounts. None of these (...) accounts are complete yet and a full explanation of the temporal asymmetry of causation will likely require contributions from all three programs. (shrink)

This paper investigates what the source of time asymmetry is in thermodynamics, and comments on the question whether a time-symmetric formulation of the Second Law is possible.

The paper tries to demonstrate that the process of the increase of entropy does not explain the asymmetry of time itself because it is unable to account for its fundamental asymmetries, that is, the asymmetry of traces (we have traces of the past and no traces of the future), the asymmetry of causation (we have an impact on future events with no possibility of having an impact on the past), and the asymmetry between the fixed (...) past and the open future, To this end, the approaches of Boltzmann, Reichenbach (and his followers), and Albert are analysed. It is argued that we should look for alternative approaches instead of this, namely we should consider a temporally asymmetrical physical theory or seek a source of the asymmetry of time in metaphysics. This second approach may even turn out to be complementary if only we accept that metaphysics can complement scientific research programmes. (shrink)

In this paper I shall try to clarify Husserl’s conception of time-consciousness. In particular, I try to explain what exactly the asymmetry between protention and retention consists in. I argue (i) that Rodemeyer’s understanding of the protention-retention relationship, as developed, seems misleading, mainly for two reasons: first, it does not take into account that the ‘now’ has duration; second, she conceives the relation between protention and retention as symmetric, (ii) that the asymmetry between protention and retention could (...) be better understood if we could not only take into account the influence that retention and affect have on protention, but also if we could take into consideration the conceptual difference between surprise and disappointment. This difference, I suggest, reveals new ways to understand the protention-retention asymmetry. (shrink)

Thermodynamics is the science that describes much of the time asymmetric behavior found in the world. This entry's first task, consequently, is to show how thermodynamics treats temporally ‘directed’ behavior. It then concentrates on the following two questions. (1) What is the origin of the thermodynamic asymmetry in time? In a world possibly governed by time symmetric laws, how should we understand the time asymmetric laws of thermodynamics? (2) Does the thermodynamic time asymmetry (...) explain the other temporal asymmetries? Does it account, for instance, for the fact that we know more about the past than the future? The discussion thus divides between thermodynamics being an explanandum or explanans. In the former case the answer will be found in philosophy of physics; in the latter case it will be found in metaphysics, epistemology, and other fields, though in each case there will be blurring between the disciplines. (shrink)

In a previous paper, we argued that death's badness consists in the deprivation of pleasurable experiences which one would have had, had one died later rather than at the time of one's actual death. Thus, we argued that death can be a bad thing for the individual who dies, even if it is an experiential blank. But there is a pressing objection to this view, for if the view is correct, then it seems that it should also be the (...) case that it is a bad thing for a person that he is born when he actually is born, rather than earlier. That is, if the deprivation account is the correct account of death's badness, then it appears that one should have symmetric attitudes to prenatal and posthumous nonexistence. But clearly we do not in general have symmetric attitudes toward the period before our birth and the period after our death; in general, we do not think of our late births as a bad thing, but we can indeed consider our early deaths as bad for us. Thus, it appears that there is a problem for the deprivation account of death's badness. (shrink)

The ancient problem of whether our asymmetrical attitudes towards time are justified remains a live one in contemporary philosophy. Drawing on themes in the work of McTaggart, Parfit, and Heidegger, I argue that this problem is also a key concern of Kierkegaard’s Either/Or. Part I of Either/Or presents the “aesthete” as living a temporally volatilized form of life, devoid of temporal location, sequence and direction. Like Parfit’s character “Timeless,” these aesthetes are indifferent to the direction of time and (...) seemingly do not experience McTaggart’s “A-Series” mode of temporality. The “ethical” conception of time that Judge William offers in Part II contains an attempt to normativize the direction of time, by re-orienting the aesthete towards an awareness of time ’s finitude. However, the form of life Judge William articulates gives time sequentiality but not necessarily the robust directionality necessary to justify our asymmetrical attitudes to time. Hence while Either/Or raises this problem it remains unanswered until The Concept of Anxiety. Only with the eschatological understanding of time developed in The Concept of Anxiety does Kierkegaard answer the question of why directional and asymmetrical conative and affective attitudes towards time are normative. (shrink)

A Brief History of Time: From the Big Bang to Black Holes is a popular-science book on cosmology (the study of the origin and evolution of the universe) by British physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for readers who have no prior knowledge of the universe and people who are interested in learning.

Responding to Hasok Chang’s vision of the history and philosophy of science as the continuation of science by other means, I illustrate the methods of HPS and their utility through a historico-critical examination of the problem of “time’s arrow‘, that is to say, the problem posed by the claim by Boltzmann and others that the temporal asymmetry of many physical processes and indeed the very possibility of identifying each of the two directions we distinguish in time must (...) have a ground in the laws of nature. I claim that this problem has proved intractable chiefly because the standard mathematical representation of time employed in the formulation of the laws of nature “forgets‘ one of the connotations of the word ”time’ as it is used in ordinary language and in experimental physics. (shrink)

There are temporal asymmetries in our attitudes towards the past and future. For example, we judge that a given amount of work is worth twice as much if it is described as taking place in the future, compared to the past :796–801, 2008). Does this temporal value asymmetry support a tensed metaphysics? By getting clear on the asymmetry’s features, I’ll argue that it doesn’t. To support a tensed metaphysics, the value asymmetry would need to not vary with (...) temporal distance, apply equally to events concerning oneself and others, and be rational and judged to be so. But evidence suggests the value asymmetry lacks these features. There are, moreover, independent arguments against its rationality. The asymmetry’s features suggest instead that it arises as an emotion-driven generalisation from a temporal bias concerning our future actions. This explanation points towards mechanisms that can play a role in explaining other instances where we generalise about the past and future, and why we’re tempted towards metaphysical pictures of time. (shrink)

A certain type of counterfactual is thought to be intimately related to causation, control, and explanation. The time asymmetry of these phenomena therefore plausibly arises from a time asymmetry of counterfactual dependence. But why is counterfactual dependence time asymmetric? The most influential account of the time asymmetry of counterfactual dependence is David Albert’s account, which posits a new, time-asymmetric fundamental physical law, the so-called “past hypothesis.” Albert argues that the time (...) class='Hi'>asymmetry of counterfactual dependence arises from holding fixed the past hypothesis when evaluating counterfactuals. In this paper, I argue that Albert’s account misconstrues the time asymmetry of counterfactual dependence. (shrink)

Microphysical laws are time reversible, but macrophysics, chemistry and biology are not. This paper explores how this asymmetry arises due to the cosmological context, where a non-local Direction of Time is imposed by the expansion of the universe. This situation is best represented by an Evolving Block Universe, where local arrows of time emerge in concordance with the Direction of Time because a global Past Condition results in the Second Law of Thermodynamics pointing to the (...) future. At the quantum level, the indefinite future changes to the definite past due to quantum wave function collapse events. (shrink)

In "Counterfactual Dependence and Time's Arrow", David Lewis defends an analysis of counterfactuals intended to yield the asymmetry of counterfactual dependence: that later affairs depend counterfactually on earlier ones, and not the other way around. I argue that careful attention to the dynamical properties of thermodynamically irreversible processes shows that in many ordinary cases, Lewis's analysis fails to yield this asymmetry. Furthermore, the analysis fails in an instructive way: it teaches us something about the connection between the (...) asymmetry of overdetermination and the asymmetry of entropy. (shrink)

An explanation of our seeming inability to influence the past.

Since the nineteenth century, the problem of the arrow of time has been traditionally analyzed in terms of entropy by relating the direction past-to-future to the gradient of the entropy function of the universe. In this paper, we reject this traditional perspective and argue for a global and non-entropic approach to the problem, according to which the arrow of time can be defined in terms of the geometrical properties of spacetime. In particular, we show how the global non-entropic (...) arrow can be transferred to the local level, where it takes the form of a non-spacelike local energy flow that provides the criterion for breaking the symmetry resulting from time-reversal invariant local laws. (shrink)

The paper reviews Balashov’s Asymmetry Thesis concerning co-existing (point-sized) enduring objects, on the one hand, and perduring ones, on the other. In this regard, it becomes crucial to investigate whether, at a given spacetime point p, it is located only the respective temporal part of a perdur- ing whole, or that whole as well. Two alternatives ought to be distinguished and, then, I will argue as follows: If the perduring whole is located where its parts are, the original (...) class='Hi'>asymmetry- thesis has to be rejected. If, however, the perduring whole is not located where its parts are, the spatiotemporal locations of the parts can no longer be used to ground the co-existence relation. But, with the modified co-existence relation the asymmetry between perdurantism and endurantism turns out to be even much stronger than it has been assumed. (shrink)

Linda Zagzebski has recently argued that there is a conflict between a common view of the asymmetry of time and various other metaphysical hypotheses. She identifies conflicts in the case of the modal arrow of time and in the case of the causal arrow of time. In the case of the modal arrow I argue that on one view there is no conflict and that on another the principle should be abandoned that there are entailments between (...) propositions about the past and the future. In the case of the causal arrow I argue that the conflict can be avoided by the adoption of a suitable closure principle. (shrink)

Textures of Time is a rich and challenging book that raises a host of important and hard questions about historical narrative, form, and style; the sociology of texts; and the core problem of ascertaining historical truth. Two that pertain to the book’s main claims are of special interest to nonspecialist readers: Is register or style—“texture”—necessarily and everywhere diagnostic of “history”? Does a new kind of “historical consciousness” emerge in south India beginning in the sixteenth century, indeed as a sign (...) of an Indian early modernity? Textures is not the first book to argue that historical discourse is constitutively marked by a peculiar style, but the claim is beset by difficulties that scholars since Barthes have detailed. Rather than textures of time—accounts of what really happened in history—what these works offer us may be only pretextures of time, textualized forms of a human experience that make claims about its degrees and types of truth through representations of various states of temporality. Instead of assessing, then, whether these works are history or something else like “myth,” we might ask whether they invite us to transcend this very dichotomy, to try, that is, to make sense of historical forms of consciousness rather than to identify forms of historical consciousness. As for modernity, nothing in south Indian historiography from 1500–1800 remotely compares to the conceptual revolution of Europe. But why should we expect the newness of the early modern world to have been experienced the same way everywhere? Modernity across Asia may have shown simultaneity without symmetry. Should this asymmetry turn out to reveal continuity and not rupture, however, no need to lament the fact. There is no shame in premodernity. (shrink)

In this course we will examine several philosophical puzzles concerning time. We all seem to experience time in a very fundamental and direct way. Yet once we begin to reflect on what time really is, it is easy to feel as puzzled as St Augustine was, who wrote: “If no one asks me, I know what [time] is. If I wish to explain it to him who asks me, I do not know.” The first set of (...) issues we will discuss concern the question whether time is ‘real.’ Time appears to consist of past, present and future. But do the past and the future exist in the same way as the present or is only the present real? Does time ‘flow’? In what ways is time different from space? What would it be to ‘spatialize’ time? Next we will ask whether certain views of time imply that there can be no freedom of the will. One might worry that if facts about the future (including facts about what I will do tomorrow) already existed in the same way as facts about the present exist, then I could not be free to choose what I will do. After all, how can I be free to decide to skip class tomorrow, if it is ‘already’ a fact today that I will attend class? What, if anything, is the connection between various views of time and ‘fatalism’? The third topic we will discuss is time travel. First we will ask whether time travel is a conceptual possibility. As we will see, there are certain conceptual puzzles associated with the possibility of time travel. For example, one might think that if time travel is possible, then I should be able to travel back in time and kill my father before the date of my conception. But this scenario seems to lead to a contradiction. Some have taken considerations such as these to argue that the very idea of time travel is incoherent. Is this right? If not, why not? Then we will look at what the theory of relativity says about the nature of time in general and about the physical possibility of time travel more specifically. Finally we will examine several issues concerning the asymmetry of time.. (shrink)

One of the more recalcitrant issues in the philosophy of time concerns the question of temporal asymmetry. Some theorists, many of them, like Einstein, physicists, believe that time is fundamentally reversible. According to this view, the physical universe is indifferent to the direction of time; consequently, something like an arrow of time is held to be a human subjective imposition on an otherwise temporally isotropic world. Another position, held by Alfred North Whitehead and contemporary process (...) philosophers, maintains that temporal asymmetry is a primitive condition of the universe, and that therefore even the most basic physical processes, such as those occurring at the subatomic level, display a distinct temporal direction. Finally, the philosopher of time J.T. Fraser (1978) claims that temporal asymmetry is an emergent feature of the universe, appearing for the first time with biogenesis. According to Fraser, with the emergence of life comes a present, or “now”, a temporal dimension whose absence in more primitive levels of cosmic evolution prohibits the attribution of an arrow of time to any pre-biotic entity. (shrink)

'The arrow of time' refers to the curious asymmetry that distinguishes the future from the past. Reversing the Arrow of Time argues that there is an intimate link between the symmetries of 'time itself' and time reversal symmetry in physical theories, which has wide-ranging implications for both physics and its philosophy. This link helps to clarify how we can learn about the symmetries of our world, how to understand the relationship between symmetries and what is (...) real, and how to overcome pervasive illusions about the direction of time. Roberts explains the significance of time reversal in a way that intertwines physics and philosophy, to establish what the arrow of time means and how we can come to know it. This book is both mathematically and philosophically rigorous yet remains accessible to advanced undergraduates in physics and the philosophy of physics. This title is also available as Open Access on Cambridge Core. (shrink)

If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future according to the Second Law of Thermodynamics, then tracing this back to the time around the Big Bang means the universe must have started off in a state of very low thermodynamic entropy: the Thermodynamic Past Hypothesis. In (...) this paper, we consider another boundary condition that plays a similar role, but for the decoherent arrow of time, i.e. the subsystems of the universe are more mixed in the future than in the past. According to what we call the Entanglement Past Hypothesis, the initial quantum state of the universe had very low entanglement entropy. We clarify the content of the Entanglement Past Hypothesis, compare it with the Thermodynamic Past Hypothesis, and identify some challenges and open questions for future research. (shrink)

One of the outstanding achievements of recent cosmology has been to offer some prospect of a unified explanation of temporal asymmetry. The explanation is in two main parts, and runs something like this. First, the various asymmetries we observe are all thermodynamic in origin – all products of the fact that we live in an epoch in which the universe is far from thermodynamic equilibrium. Second, this thermodynamic disequilibrium is associated with the condition of the universe very soon after (...) the Big Bang – the essential point being that in the rapidly expanding universe of the time, gravity is able to create organisation much faster than other processes can destroy it. The stars, galaxies and other forms of organisation we find in the present universe are all products of this early period. Such concentrated energy sources themselves make possible the kinds of asymmetric phenomena with which we are most familiar, such as life itself. If this explanation proves to be right it will surely rank as one of the most impressive achievements in the whole of natural philosophy. Where else do we find this breathtaking scale, this extraordinary conjunction of fundamental physics, the first moments of Creation, the possibility of life and the basic character of human experience? And it is very much a contemporary achievement: even if its roots go back on one side to the investigation of time asymmetry in nineteenth century statistical mechanics, and on the other to Hubble's discovery in the 1920's of the expansion of the universe, the body of the picture has only begun to be filled in in the last twenty or thirty years. This fascinating story has recently been given some well-deserved publicity in Stephen Hawking's bestseller, A Brief History of Time – well-deserved, not least, because Hawking himself is responsible for a considerable part of the story as it presently stands. (shrink)

What is the relationship between space and time in the human mind? Studies in adults show an asymmetric relationship between mental representations of these basic dimensions of experience: Representations of time depend on space more than representations of space depend on time. Here we investigated the relationship between space and time in the developing mind. Native Greek‐speaking children watched movies of two animals traveling along parallel paths for different distances or durations and judged the spatial and (...) temporal aspects of these events (e.g., Which animal went for a longer distance, or a longer time?). Results showed a reliable cross‐dimensional asymmetry. For the same stimuli, spatial information influenced temporal judgments more than temporal information influenced spatial judgments. This pattern was robust to variations in the age of the participants and the type of linguistic framing used to elicit responses. This finding demonstrates a continuity between space‐time representations in children and adults, and informs theories of analog magnitude representation. (shrink)

Some argue that time’s causal arrow is grounded in an underlying thermodynamic asymmetry. Often, this is tied to Humean skepticism that causes produce their effects, in any robust sense of ‘produce’. Conversely, those who advocate stronger notions of natural necessity often reject thermodynamic reductions of time’s causal arrow. Against these traditional pairings, I argue that ‘reduction-plus-production’ is coherent. Reductionists looking to invoke robust production can insist that there are metaphysical constraints on the signs of objects’ velocities in (...) any state, given other—including far later—states’ properties. The Past Hypothesis may thus be a metaphysical condition, not a physical law. (shrink)

The received view on the problem of the direction of time holds it that time has no intrinsic dynamical properties, and that its apparent asymmetry, to be understood in purely topological terms, is dependent on the directional properties of physical processes. In this paper we shall challenge both claims, in the light of an algebraic representation of time. First, we will show how to give a precise formulation to the intuitive idea that time possesses an (...) intrinsic dynamics; this formulation relies on the fact that the algebraic properties of time can equivalently be understood in dynamical terms. Second, we shall argue that the directional properties displayed by the processes occurring in time depend on the directional properties of time, rather than the converse. (shrink)

Why does time appear to run in only one direction? We remember the past- but why not the future? We can influence the future- but could we, even theoretically, influence the past? Generations of philosophers and theologians, physicists and mathematicians have puzzles and speculated about these and the many other questions that surround the concept of time. Recent scientific work is said to explain the directionality of time. But time still contains many mysteries- black holes and (...) big bangs, asymmetries and relativities, arrows and loops - that will doubtless continue to occupy us for centuries to come. In this impressive collection of original articles ten internationally known scholars explore and explains the nature of time, apace and now space-time. Founded on the latest developments in thermodynamics, quantum theory and cosmology, their ideas will fascinate anyone interested in Einstein's theory of relativity. (shrink)