Huw Price

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

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

Newcomb problems turn on a 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. 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 only follow beliefs about chances in the absence of "inadmissible evidence". In this paper I exhibit a tension in Lewis’s views on these two matters. I present a class of decision problems –- actually, I argue, a species of Newcomb problem –- in which Lewis’s view of the relevance of inadmissible evidence seems to recommend one-boxing, while his causal decision theory recommends two-boxing. I propose a diagnosis for this dilemma, and suggest 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 dissolves many apparent Newcomb problems, and makes one-boxing non-controversial in those that remain.

Wittgenstein is often thought to have challenged the view that assertion is an important theoretical category in a philosophical view of language. One of Wittgenstein’s main themes in the early sections of the Investigations is that philosophy misses important distinctions about the uses of language, distinctions hidden from us by ‘the uniform appearances of words.’ (1968, #11) As Wittgenstein goes on to say: It is like looking into the cabin of a locomotive. We see handles all looking more or less alike. (Naturally, since they are all supposed to be handled.) But one is the handle of a crank which can be moved continuously (it regulates the opening of a valve); another is the handle of a switch, which has only two effective positions, it is either off or on; a third is the handle of a brake-lever, the harder one pulls on it, the harder it brakes; a fourth, the handle of a pump: it has an effect only so long as it is moved to and fro. (1968, #12) Few contemporary philosophers share Wittgenstein’s evident familiarity with cabin of a steam locomotive, and in general, most of us are increasingly remote from all but the most superficial understanding of the underlying functions of the tools on which we rely. So we are perhaps even more prone to the mistake that Wittgenstein thinks that philosophy makes with respect to language, that of regarding it as one tool rather than many: ‘Think of the tools in a tool-box: there is a hammer, pliers, a saw, a screw-driver, a rule, a glue-pot, glue, nails and screws.—The functions of words are as diverse as the functions of these objects.’1 (1968, #11)

This paper suggests a novel reinterpretation of the mathematical core of Wheeler-Feynman absorber theory, and hence a new route to the conclusion that the temporal asymmetry of classical electromagnetic radiation has the same origin as that of thermodynamics. The argument begins (Sec. 2) with a careful analysis of what the apparent asymmetry of radiation actually involves. Two major flaws in the standard version of the Wheeler-Feynman treatment of radiative asymmetry are then identified (Secs. 4–5), and the proposed reinterpretation is described (Sec. 6). This avoids the two flaws previously mentioned, and also the problematic dependence of radiation on cosmological structure