Huw Price

argues that the success of the backward causation hypothesis in quantum mechanics would provide strong support for a version of Reichenbach's account of the direction of causal processes, which takes the direction of causation to rest on the fork asymmetry. He also criticises my perspectival account of the direction of causation, which takes causal asymmetry to be a projection of our own temporal asymmetry as agents. In this reply I take issue with Dowe's argument at three main points: his claim that the backward causation hypothesis in QM is incompatible with my perspectival approach to the direction of causation; his defence of the fork asymmetry approach against a general criticism of mine based on the time-symmetry of microphysics; and his application of his preferred account of the direction of causal processes to the relevant cases in QM.

Can an agent deliberating about an action A hold a meaningful credence that she will do A? 'No', say some authors, for 'Deliberation Crowds Out Prediction' (DCOP). Others disagree, but we argue here that such disagreements are often terminological. We explain why DCOP holds in a Ramseyian operationalist model of credence, but show that it is trivial to extend this model so that DCOP fails. We then discuss a model due to Joyce, and show that Joyce's rejection of DCOP rests on terminological choices about terms such as 'intention', 'prediction', and 'belief'. Once these choices are in view, they reveal underlying agreement between Joyce and the DCOP-favouring tradition that descends from Ramsey. Joyce's Evidential Autonomy Thesis (EAT) is effectively DCOP, in different terminological clothing. Both principles rest on the so-called 'transparency' of first-person present-tensed reflection on one's own mental states.

The best case for thinking that quantum mechanics is nonlocal rests on Bell's Theorem, and later results of the same kind. However, the correlations characteristic of Einstein–Podolsky–Rosen (EPR)–Bell (EPRB) experiments also arise in familiar cases elsewhere in quantum mechanics (QM), where the two measurements involved are timelike rather than spacelike separated; and in which the correlations are usually assumed to have a local causal explanation, requiring no action-at-a-distance (AAD). It is interesting to ask how this is possible, in the light of Bell's Theorem. We investigate this question, and present two options. Either (i) the new cases are nonlocal too, in which case AAD is more widespread in QM than has previously been appreciated (and does not depend on entanglement, as usually construed); or (ii) the means of avoiding AAD in the new cases extends in a natural way to EPRB, removing AAD in these cases too. There is a third option, viz., that the new cases are strongly disanalogous to EPRB. But this option requires an argument, so far missing, that the physical world breaks the symmetries which otherwise support the analogy. In the absence of such an argument, the orthodox combination of views—action-at-a-distance in EPRB, but local causality in its timelike analogue—is less well established than it is usually assumed to be. 1 Introduction1.1 Background1.2 Outline of the argument2 The Experiments2.1 Standard EPRB2.2 Sideways EPRB2.3 Comparing the experiments2.4 The need for beables3 The Symmetry Considerations3.1 The action symmetry3.2 Time-symmetry in SEPRB4 The Basic Trilemma4.1 An intuitive defence of Option III?5 Avoiding the Trilemma?6 The Classical Objection7 Defending Option III7.1 The free will argument7.2 Independence and consistency8 Entanglement and Epistemic Perspective

The dustjacket of The Common Mind bears a photograph of the traffic at a Sydney intersection on a wet winter’s evening in 1938. It is rush hour, and the homeward traffic conveys a fine sense of common purpose. The scene has a special resonance for me, for I stood at that very spot with my parents and brothers one similar evening in 1966, on the day we first arrived in Australia. There was a marked pedestrian crossing there then, which we set out to negotiate, taking it for granted that the relevant conventions were those we were used to in rural England. But pedestrians and rush hour traffic were both under the control of a policeman—one of his predecessors can be seen in the photograph—who had just given the traffic priority. He loudly familiarised us with the local customs, and the kind of emotions we felt play an important part in Philip Pettit’s vision of the possibility and grounds of a satisfactory human society: the approval and disapproval of the community provides an intangible hand that guides defaulters into line.

Causalists and Evidentialists can agree about the right course of action in an (apparent) Newcomb problem, if the causal facts are not as initially they seem. If declining $1,000 causes the Predictor to have placed $1m in the opaque box, CDT agrees with EDT that one-boxing is rational. This creates a difficulty for Causalists. We explain the problem with reference to Dummett's work on backward causation and Lewis's on chance and crystal balls. We show that the possibility that the causal facts might be properly judged to be non-standard in Newcomb problems leads to a dilemma for Causalism. One horn embraces a subjectivist understanding of causation, in a sense analogous to Lewis's own subjectivist conception of objective chance. In this case the analogy with chance reveals a terminological choice point, such that either (i) CDT is completely reconciled with EDT, or (ii) EDT takes precedence in the cases in which the two theories give different recommendations. The other horn of the dilemma rejects subjectivism, but now the analogy with chance suggests that it is simply mysterious why causation so construed should constrain rational action.

There is a long-standing disagreement in the philosophy of probability and Bayesian decision theory about whether an agent can hold a meaningful credence about an upcoming action, while she deliberates about what to do. Can she believe that it is, say, 70% probable that she will do A, while she chooses whether to do A? No, say some philosophers, for Deliberation Crowds Out Prediction (DCOP), but others disagree. In this paper, we propose a valid core for DCOP, and identify terminological causes for some of the apparent disputes.

A number of writers have been attracted to the idea that some of the peculiarities of quantum theory might be manifestations of 'backward' or 'retro' causality, underlying the quantum description. This idea has been explored in the literature in two main ways: firstly in a variety of explicit models of quantum systems, and secondly at a conceptual level. This note introduces a third approach, intended to complement the other two. It describes a simple toy model, which, under a natural interpretation, shows how retrocausality can emerge from simple global constraints. The model is also useful in permitting a clear distinction between the kind of retrocausality likely to be of interest in QM, and a different kind of reverse causality, with which it is liable to be confused. The model is proposed in the hope that future elaborations might throw light on the potential of retrocausality to account for quantum phenomena.

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

The paper criticizes the attempt to account for the direction of causation in terms of objective statistical asymmetries, such as those of the fork asymmetry. Following Ramsey, I argue that the most plausible way to account for causal asymmetry is to regard it as "put in by hand", that is as a feature that agents project onto the world. Its temporal orientation stems from that of ourselves as agents. The crucial statistical asymmetry is an anthropocentric one, namely that we take our actions to be statistically independent of everything except (what we come to call) their effects. I argue that this account explains the intuitive plausibility of Reichenbach's principle of the common cause

Summary: Contemporary writers often claim that chaos theory explains the thermodynamic arrow of time. This paper argues that such claims are mistaken, on two levels. First, they underestimate the difficulty of extracting asymmetric conclusions from symmetric theories. More important, however, they misunderstand the nature of the puzzle about the temporal asymmetry of thermodynamics, and simply address the wrong issue. Both of these are old mistakes, but mistakes which are poorly recognised, even today. This paper aims to lay bare the mistakes in their classical (pre-chaos theory) manifestations, in order to make it clear that chaos theory cannot possibly do better

In “A Subjectivist’s Guide to Objective Chance,” David Lewis says that he is “led to wonder whether anyone but a subjectivist is in a position to understand objective chance.” The present essay aims to motivate this same Lewisean attitude, and a similar degree of modest subjectivism, with respect to objective causation. The essay begins with Newcomb problems, which turn on an apparent tension between two principles of choice: roughly, a principle sensitive to the causal features of the relevant situation, and a principle sensitive only to evidential factors. Two-boxers give priority to causal beliefs, and one-boxers to evidential beliefs. The essay notes that a similar issue can arise when the modality in question is chance, rather than causation. In this case, the conflict is between decision rules based on credences guided solely by chances, and rules based on credences guided by other sorts of probabilistic evidence. Far from excluding cases of the latter kind, Lewis’s Principal Principle explicitly allows for them, in the form of the caveat that credences should follow beliefs about chances only in the absence of “inadmissible evidence.” The essay then exhibits a tension in Lewis’s views on these two matters, by presenting a class of decision problems—some of them themselves Newcomb problems—in which Lewis’s view of the relevance of inadmissible evidence seems in tension with his causal decision theory. It offers a diagnosis for this dilemma and proposes a remedy, based on an extension of a proposal due to Ned Hall and others from the case of chance to that of causation. The remedy suggests a new view of the relation between causal decision theory and evidential decision theory, namely, that they stand to each other much as chance stands to credence, being objective and subjective faces of the same practical coin. This has much the same metaphysical benefits as Lewis’s own view of chance and also throws interesting new light on Newcomb problems, providing an irenic resolution of the apparent disagreement between causal and evidential decision rules.

Bell’s theorem requires the assumption that hidden variables are independent of future measurement settings. This independence assumption rests on surprisingly shaky ground. In particular, it is puzzlingly time-asymmetric. The paper begins with a summary of the case for considering hidden variable models which, in abandoning this independence assumption, allow a degree of ‘backward causation’. The remainder of the paper clarifies the physical significance of such models, in relation to the issue as to whether quantum mechanics provides a complete description of physical reality

For more than a century, physics has known of a puzzling conflict between the T- asymmetry of thermodynamic phenomena and the T-symmetry of the underlying microphysics on which these phenomena depend. This paper provides a guide to the current status of this puzzle, distinguishing the central issue from various issues with which it may be confused. It is shown that there are two competing conceptions of what is needed to resolve the puzzle of the thermodynamic asymmetry, which differ with respect to the number of distinct T-asymmetries they take to be manifest in the physical world. On the preferable one-asymmetry conception, the remaining puzzle concerns the ordered distribution of matter in the early universe. The puzzle of the thermodynamic arrow thus becomes a puzzle for cosmology