Huw Price

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.

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

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

This paper revisits some views about negation I defended in two early papers. Some of the themes of those papers have been developed sympathetically in recent work by Tim Smiley, Lloyd Humberstone and Ian Rumfitt. However, Rumfitt and Peter Gibbard have both criticised arguments I offered in defence of Double Negation Elimination (DNE), against a Dummettian intuitionist. I reconsider those arguments, arguing that although they survive Rumfitt’s and Gibbard’s attacks, the case against Dummett is for other reasons less straightforward than I took it to be. With reference to Rumfitt’s own defence of DNE, I call attention to the attractions of the view defended in my second paper that negation has dialectical origins. I also point out some difficulties for this view which seem to have been overlooked by previous writers, including me

I distinguish three views, a defence of any one of which would go some way towards vindicating the view that there is something objective about the passage of time: the view that the present moment is objectively distinguished; the view that time has an objective direction – that it is an objective matter which of two non-simultaneous events is the earlier and which the later; the view that there is something objectively dynamic, flux-like, or "flow-like" about time. I argue that each of these views is not so much false as doubtfully coherent. In each case, it turns out to be hard to make sense of what the view could be, at least if it is to be non-trivial, and of use to a friend of objective passage. I conclude with some remarks about avenues that seem worth exploring in the philosophy of time, when we are done with trying to make sense of passage

The so-called Canberra Plan is a grandchild of the Ramsey-Carnap treatment of theoretical terms. In its original form, the Ramsey-Carnap approach provided a method for analysing the meaning of scientific terms, such as “electron”, “gene” and “quark”—terms whose meanings could plausibly be delineated by their roles within scientific theories. But in the hands of David Lewis (1970, 1972), the original approach begat a more ambitious descendant, generalised and extended in two distinct ways: first, Lewis applied the technique to analyse the meaning of terms introduced not just by explicit scientific theories, but also by implicit folk theories such as folk psychology; second, he supplemented the theory to provide an account of the way in which the referents of the analysed terms might be identified on the basis of empirical investigation.

In a recent paper, Richard Rorty begins by telling us why pragmatists such as himself are inclined to identify truth with justification: ‘Pragmatists think that if something makes no difference to practice, it should make no difference to philosophy. This conviction makes them suspicious of the distinction between justification and truth, for that distinction makes no difference to my decisions about what to do.’ (1995, p. 19) Rorty goes on to discuss the claim, defended by Crispin Wright, that truth is a normative constraint on assertion. He argues that this claim runs foul of this principle of no difference without a practical difference: ‘The need to justify our beliefs to ourselves and our fellow agents subjects us to norms, and obedience to these norms produces a behavioural pattern that we must detect in others before confidently attributing beliefs to them. But there seems to be no occasion to look for obedience to an additional norm – the commandment to seek the truth. For – to return to the pragmatist doubt with which I began – obedience to that commandment will produce no behaviour not produced by the need to offer justification.’ (1995, p. 26) Again, then, Rorty appeals to the claim that a commitment to a norm of truth rather than a norm of justification makes no behavioural difference. This is an empirical claim, testable in principle by comparing the behaviour of a community of realists (in Rorty’s sense) to that of a community of pragmatists. In my view, the experiment would show that the claim is unjustified, indeed false. I think that there is an important and widespread behavioural pattern that depends on the fact that speakers do take themselves to be subject to such an additional norm. Moreover, it is a..

I once stood staring at a map in a large US airport, looking for an ATM. Next to me a couple also stared at the map, trying to figure out where in the airport they were. “Sheesh!” said the male at last, pointing to the red dot and the words ‘You are here’ in the key beside the map: “We’re way over here, right off the map!” Jenann Ismael’s understanding of red dots lies very much at the other extreme, but self-location – the task that couple were engaged in, however haplessly – is the unifying theme of The Situated Self. In Ismael’s hands, it is a thread that turns out to tie together a remarkable range of topics. Imagine being taken on a tour of your own home town, weaving in and out through various neighbourhoods, familiar and less so, and ducking between them via surprising paths and shortcuts. (“This next to that? Who knew!”) The Situated Self is that kind of book – an exhilarating and often demanding excursion, startling in its breadth and the ways it relates seemingly unconnected topics. Although the route of Ismael's tour is often highly original, the vehicle itself has a familiar shape, at least in outline. Ismael builds a chassis to specifications due especially to John Perry, fits it out to her own requirements, and then shows us where it can take us. Mostly, I found the excursion convincing, as well as fascinating. In what follows, I shall take up one case in which I was not convinced, and then raise an issue about another destination – somewhere in the same vicinity, apparently – and ask whether Ismael’s bus takes us there, too. First, though, to the fundamentals, as Ismael develops them

It is often objected that the Everett interpretation of QM cannot make sense of quantum probabilities, in one or both of two ways: either it can’t make sense of probability at all, or it can’t explain why probability should be governed by the Born rule. David Deutsch has attempted to meet these objections. He argues not only that rational decision under uncertainty makes sense in the Everett interpretation, but also that under reasonable assumptions, the credences of a rational agent in an Everett world should be constrained by the Born rule. David Wallace has developed and defended Deutsch’s proposal, and greatly clarified its conceptual basis. In particular, he has stressed its reliance on the distinguishing symmetry of the Everett view, viz., that all possible outcomes of a quantum measurement are treated as equally real. The argument thus tries to make a virtue of what has usually been seen as the main obstacle to making sense of probability in the Everett world. In this note I outline some objections to the Deutsch-Wallace argument, and to related proposals by Hilary Greaves about the epistemology of Everettian QM. (In the latter case, my arguments include an appeal to an Everettian analogue of the Sleeping Beauty problem.) The common thread to these objections is that the symmetry in question remains a very significant obstacle to making sense of probability in the Everett interpretation.

It has been suggested that some of the puzzles of QM are resolved if we allow that there is retrocausality in the quantum world. In particular, it has been claimed that this approach offers a path to a Lorentz-invariant explanation of Bell correlations, and other manifestations of quantum "nonlocality", without action-at-a-distance. Some writers have suggested that this proposal can be supported by an appeal to time-symmetry, claiming that if QM were made "more time-symmetric", retrocausality would be a natural consequence. Critics object that there is complete time-symmetry in classical physics, and yet no apparent retrocausality. Why should QM be any different? In this note I call attention to a respect in which QM is different, under some assumptions about quantum ontology. Under these assumptions, the option of time-symmetry without retrocausality is not available in QM, for reasons intimately connected with the fundamental differences between classical and quantum physics (especially the role of discreteness in the latter).