Huw Price

In many physical systems, coupling forces provide a way of carrying the energy stored in adjacent harmonic oscillators from place to place, in the form of waves. The wave equations governing such phenomena are time-symmetric: they permit the opposite processes, in which energy arrives at a point in the form of incoming concentric waves, to be lost to some external system. But these processes seem rare in nature. What explains this temporal asymmetry, and how is it related to the thermodynamic asymmetry? This paper attempts to clarify these old issues, in the light of recent contributions. After brief introductory remarks (§1), the paper is in three main parts. §2 examines the so-called ‘Sommerfeld Radiation Condition’, arguing that its link to the observed asymmetry is much less direct than commonly supposed. §3 begins with Zeh's proposal to make the Sommerfeld condition an ingredient in an explanation of the observed asymmetry, and makes explicit a useful distinction between two ways in which the thermodynamic asymmetry might connect to the radiation asymmetry. §4 reviews a proposal I have defended in earlier work about the relation of the radiative asymmetry to that of thermodynamics, and defends it against recent objections by Zeh and Frisch. I also distinguish it from a recent proposal due to North. I agree with North that the observed asymmetry of radiation stems from the low entropy history, but argue that she mis-characterises the asymmetry, and hence misses a crucial element in a proper account of the role of the low entropy past.

In this paper we defend the view that the ordinary notions of cause and effect have a direct and essential connection with our ability to intervene in the world as agents.1 This is a well known but rather unpopular philosophical approach to causation, often called the manipulability theory. In the interests of brevity and accuracy, we prefer to call it the agency theory.2 Thus the central thesis of an agency account of causation is something like this: an event A is a cause of a distinct event B just in case bringing about the occurrence of A would be an effective means by which a free agent could bring about the occurrence of B. In our view the unpopularity of the agency approach to causation may be traced to two factors. The first is a failure to appreciate certain distinctive advantages that this approach has over its various rivals. We have drawn attention to some of these advantages elsewhere, and we summarize below. However, the second and more important factor is the influence of a number of stock objections, objections that seem to have persuaded many philosophers that agency accounts face insuperable obstacles. In this paper we want to show that these objections have been vastly overrated. There are four main objections

It has often been suggested that retrocausality offers a solution to some of the puzzles of quantum mechanics: e.g., that it allows a Lorentz-invariant explanation of Bell correlations, and other manifestations of quantum nonlocality, without action-at-a-distance. Some writers have argued that time-symmetry counts in favour of such a view, in the sense that retrocausality would be a natural consequence of a truly time-symmetric theory of the quantum world. Critics object that there is complete time-symmetry in classical physics, and yet no apparent retrocausality. Why should the quantum world be any different? This note throws some new light on these matters. I call attention to a respect in which quantum mechanics is different, under some assumptions about quantum ontology. Under these assumptions, the combination of time-symmetry without retrocausality is unavailable in quantum mechanics, for reasons intimately connected with the differences between classical and quantum physics (especially the role of discreteness in the latter). Not all interpretations of quantum mechanics share these assumptions, however, and in those that do not, time-symmetry does not entail retrocausality.

[email: [email protected]] If recent literature is to be our guide, the main place of philosophy in the study of the mind would seem to be to determine the place of psychology in the study of the world. One distinctive kind of answer to this question begins by noting the central role of intentionality in psychology, and goes on to argue that this sets psychology apart from the natural sciences. Sometimes to be thus set apart is to be exiled, or rejected, but more often it is a protective move, intended to show that psychology is properly insulated from the reductionist demands of natural science. I am interested here in the general issue as to how this move to insulate intentional psychology should best be characterised-how to make sense of the idea that there can be a legitimate enterprise of this kind. I shall concentrate on what is perhaps the best known version of such a view, that of Daniel Dennett. I think that my conclusions apply to other versions as well, but Dennett provides a particularly accessible example

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.

Concepts employed in folk descriptions of the world often turn out to be more perspectival than they seem at first sight, involving previously unrecognised sensitivity to the viewpoint or 'situation' of the user of the concept in question. Often, it is progress in science that reveals such perspectivity, and the deciding factor is that we realise that other creatures would apply the same concepts with different extension, in virtue of differences between their circumstances and ours. In this paper I argue that causal concepts are perspectival in this way, and describe the 'situation' on which they depend in terms of an abstract characterisation of the viewpoint of a deliberating agent. I argue that this approach makes better sense than rivals of the apparent asymmetry and temporal orientation of the causal relation.

Late in the nineteenth century, physics noticed a puzzling conflict between the laws of physics and what actually happens. The laws make no distinction between past and future—if they allow a process to happen one way, they allow it in reverse.1 But many familiar processes are in practice ‘irreversible’, common in one orientation but unknown ‘backwards’. Air leaks out of a punctured tyre, for example, but never leaks back in. Hot drinks cool down to room temperature, but never spontaneously heat up. Once we start looking, these examples are all around us—that’s why films shown in reverse often look odd. Hence the puzzle: What could be the source of this widespread temporal bias in the world, if the underlying laws are so even-handed? Call this the Puzzle of Temporal Bias, or PTB for short. It’s an oft-told tale how other puzzles of the late nineteenth century soon led to the two most famous achievements of twentieth century physics, relativity and quantum mechanics. Progress on PTB was much slower, but late in the twentieth century cosmology provided a spectacular answer, or partial answer, to this deep puzzle. Because the phenomena at the heart of PTB are so familiar, so ubiquitous, and so crucial to our own existence, the achievement is one of the most important in the entire history of physics. Yet it is littleknown and underrated, at least compared to the other twentieth century solutions to nineteenth century puzzles. Why is it underrated? Partly because people underestimate the original puzzle, or misunderstand it, and so don’t see what a big part of it is addressed by the new cosmology. And partly for a deeper, more philosophical reason, connected with the view that we don’t need to explain initial conditions. This has two effects. First, people undervalue the job done so far by cosmology, in telling us something very surprising..

Pragmatists recommend that in approaching a problematic concept in philosophy, we should begin by examining the role it plays in the practical, cognitive and linguistic lives of the creatures who use it. This paper stems from an interest in pragmatic accounts, in this sense, of the various modal notions we encounter in science. I propose that pragmatists about these notions should avail themselves of the vocabulary of theoretical models. This vocabulary brings to the foreground the issues of function, use and role in practice, on which pragmatists want to focus; while downplaying the naive representationalism that pragmatists see as an impediment to good philosophy. I show how this framework may be used to delineate a kind of pragmatic perspectivalism about probability, and argue that the same template offers a promising way to make sense of the link between causation and manipulability.

Proponents of causal decision theories argue that classical Bayesian decision theory (BDT) gives the wrong advice in certain types of cases, of which the clearest and commonest are the medical Newcomb problems. I defend BDT, invoking a familiar principle of statistical inference to show that in such cases a free agent cannot take the contemplated action to be probabilistically relevant to its causes (so that BDT gives the right answer). I argue that my defence does better than those of Ellery Eells and Richard Jeffrey; and that it applies, where necessary, to other types of Newcomb problem.

In the first chapter of From Metaphysics to Ethics, Frank Jackson begins, as he puts it, ‘by explaining how serious metaphysics by its very nature raises the location problem.’ (1998, p. 1) He gives us two examples of location problems. The first concerns semantic properties, such as truth and reference: Some physical structures are true. For example, if I were to utter a token of the type ‘Grass is green’, the structure I would thereby bring into existence would be true ... How are the semantic properties of the sentence related to the non-semantic properties of the sentence? Where, if anywhere, are the semantic properties of truth, content and reference to be found in the non-semantic, physical or naturalistic account of the sentence?’ (1998, p. 2) Jackson notes two possible answers to questions of this kind. The first denies that there are any such semantic properties

One of the jobs of philosophers of the special sciences is to connect the local concerns of particular disciplines with those of philosophy in general. The two-way complexities of this task are well-illustrated by the case of causation. On the one hand—from the outside, as it were— philosophers interested in general issues about causation are prone to turn to the special sciences for real-life examples of the use of causal notions. On the other hand, from the inside, the special disciplines themselves throw up philosophical puzzles in which the notion of causation plays a role. When does correlation indicate causation, for example? Physics and economics both generate hard cases of this kind