This chapter is concerned with the representation of time and change in classical (i.e., non-quantum) physical theories. One of the main goals of the chapter is to attempt to clarify the nature and scope of the so-called problem of time: a knot of technical and interpretative problems that appear to stand in the way of attempts to quantize general relativity, and which have their roots in the general covariance of that theory. The most natural approach to these questions is via (...) a consideration of more clear cases. So much of the chapter is given over to a discussion of the representation of time and change in other, better understood theories, starting with the most straightforward cases and proceeding through a consideration of cases that lead up to the features of general relativity that are responsible for the problem of time. (shrink)

Static Maxwell-Einstein continuum mechanical gravitoelectromagnetic total stress energy momentum density tensor eigenvector matrix configuration space, provides flux for time dependent quantum mechanical eigenvalue matrix operator observables via Dirac-Noether conserved angular momentum probability current symmetry. Fundamental quantum continuum
equation returns eigenvalues of photon gravitoelectromagnetic spectrum in units of Maxwell stress tensor pascals. Energization of off-diagonal stress tensor components results in electron-positron (moment of inertia x angular velocity) angular momentum origin of particle wave mass charge eigenvalues. In thought experiment test vs. general (...) theory via pp-waves microlensing problem, where light-to-light gravitational attraction is four times matter-to-matter attraction, hypothesis predicts null result in area general theory known to break down on microscopic scale.
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Or better: time asymmetry in thermodynamics. Better still: time asymmetry in thermodynamic phenomena. “Time in thermodynamics” misleadingly suggests that thermodynamics will tell us about the fundamental nature of time. But we don’t think that thermodynamics is a fundamental theory. It is a theory of macroscopic behavior, often called a “phenomenological science.” And to the extent that physics can tell us about the fundamental features of the world, including such things as the nature of time, we generally think that only fundamental (...) physics can. On its own, a science like thermodynamics won’t be able to tell us about time per se. But the theory will have much to say about everyday processes that occur in time; and in particular, the apparent asymmetry of those processes. The pressing question of time in the context of thermodynamics is about the asymmetry of things in time, not the asymmetry of time, to paraphrase Price ( , ). I use the title anyway, to underscore what is, to my mind, the centrality of thermodynamics to any discussion of the nature of time and our experience in it. The two issues—the temporal features of processes in time, and the intrinsic structure of time itself—are related. Indeed, it is in part this relation that makes the question of time asymmetry in thermodynamics so interesting. This, plus the fact that thermodynamics describes a surprisingly wide range of our ordinary experience. We’ll return to this. First, we need to get the question of time asymmetry in thermodynamics out on the table. (shrink)

Special relativity is most naturally formulated as a theory of spacetime geometry, but within the spacetime framework probability appears to be a purely epistemic notion. It is possible that progress can be made with rather different approaches - covariant stochastic equations, in particular - but the results to date are not encouraging. However, it seems a non-epistemic notion of probability can be made out in Minkowski space on Everett's terms. I shall work throughout with the consistent histories formalism. I shall (...) start with a conservative interpretation, and then go on to Everett's. (shrink)

A standard objection to the moving spotlight theory of time is that it is incompatible with special relativity. I show how to formulate the moving spotlight theory so that it is perfectly compatible with special relativity. There is no need to re-interpret the physics or add to it a notion of absolute simultaneity.

No one denies that time and space are different; and it is easy to catalog differences between them. I can point my finger toward the west, but I can’t point my finger toward the future. If I choose, I can now move to the left, but I cannot now choose to move toward the past. And (as D. C. Williams points out) for many of us, our attitudes toward time differ from our attitudes toward space. We want to maximize our (...) temporal extent and minimize our spatial extent: we want to live as long as possible but we want to be thin.1 But these differences are not very deep, and don’t get at the essence of the difference between time and space. That’s what I want to understand: I want to know what makes time different from space. I want to know which difference is the fundamental difference between them. (shrink)

The present paper aims to contribute to the substantivalism versus relationalism debate and to defend general relativity (GR) against pseudoscientific attacks in a novel, especially inclusive way. This work was initially motivated by the desire to establish the incompatibility of any ether theories with accelerated cosmic expansion and inflation (motto: where would a hypothetical medium supposedly come from so fast?). The failure of this program is of interest for emergent GR concepts in high energy particle physics. However, it becomes increasingly (...) important to guard scientific results against their misrepresentation by fundamentally anti-scientific agendas. We therefore argue that although it is not known whether the perceived space-time is fundamental (rather than a condensed state or a particular membrane), in a fundamental theory, space-time must be abstract relational: fundamental space-time is the consistent spatial-temporal arrangement of events. To pursue its own goals, this work should be accessible to a wide audience: physicists, philosophers of science, those being tempted by anti-relativity theories, but also those who vigorously defend some orthodox relativity that is not actually supported by GR. It must thus be extensive in order to satisfy the different parties’ desire to have included and understood their respective positions. (shrink)