Bradford Skow

Bohmian mechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equation work just as well as the official guidance equation. One way to argue that the guidance equation is superior to its rivals is to use a symmetry argument: of the candidate guidance equations, the official guidance equation is the simplest Galilean-invariant candidate. This symmetry argument---if it worked---would solve the underdetermination problem. But the argument does not work. It fails because it rests on assumptions about how Galilean transformations (especially boosts) act on the wavefunction that are (in this context) unwarranted. My discussion has larger morals about the physical significance of certain mathematical results (like, for example, Wigner's theorem) in non-orthodox interpretations of quantum mechanics.

It is better when people get what they deserve. So we need an axiology according to which the intrinsic value of a possible world is a function of both how well-off and how deserving the people in that world are. But how should these ?desert-adjusted? values of possible worlds be calculated? It is easy to come up with some qualitative ideas. But these qualitative ideas leave us with an embarrassment of riches: too many quantitative functions that implement those qualitative ideas. In this paper I will select one of these quantitative functions and defend its superiority

According to the moving spotlight theory of time, the property of being present moves from earlier times to later times, like a spotlight shone on spacetime by God. In more detail, the theory has three components. First, it is a version of eternalism: all times, past present and future, exist. (Here I use “exist” in its tenseless sense.) Second, it is a version of the A-theory of time: there are nonrelative facts about which times are past, which time is present, and which times are future. That is, it is not just that the year 1066 is past relative to 2007. The year 1066 is also past full-stop, not relative to any other time. (The A-theory is opposed to the B-theory of time, which says that facts about which times are past are relative to other times.) And third, on this view the passage of time is a real phenomenon. Which moment is present keeps changing. As I will sometimes put it, the NOW moves from the past toward the future.1 And this does not mean that relative to different times, different times are present. Even the B-theory can say that 1999 is present relative to 1999 but is not present relative to 2007. No, according to the moving spotlight theory, the claim that which moment is present keeps changing is supposed to be true, even from a perspective outside time.

A desert-sensitive moral theory says that whether people get what they deserve, whether they are treated as they deserve to be treated, plays a role in determining what we ought to do. Some popular forms of consequentialism are desert-sensitive. But where do facts about what people deserve come from? If someone deserves a raise, or a kiss, in virtue of what does he deserve those things? One plausible answer is that what someone deserves depends, at least in part, on how well he meets his moral requirements. The wicked deserve to suffer and the decent do not. Shelly Kagan (2006) has argued that this plausible answer is wrong. But his argument for that conclusion does not succeed. I will show how to formulate a desert-sensitive moral theory (and also a desert-sensitive version of consequentialism) on which this answer is correct

This book first argues that what philosophers are really after, or at least should be after, when they seek a theory of explanation, is a theory of answers to why-questions. The book's main thesis, then, is a theory of reasons why. Every reason why some event happened is either a cause, or a ground, of that event. Challenging this thesis are many examples philosophers have thought they have found of "non-causal explanations." Reasons Why uses two ideas to show that these examples are not counterexamples to the theory it defends. First is the idea that not every part of a good response to a why-question is part of an answer to that why-question. Second is the idea that not every reason why something is a reason why an event happened is itself a reason why that event happened.

Bohmian mechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equa- tion work just as well as the official guidance equation. Dürr, Goldstein, and Zanghì have argued that of the candidate guidance equations, the official guid- ance equation is the simplest Galilean-invariant candidate. This symmetry argument—if it worked—would solve the underdetermination problem. But the argument does not work. It fails because it rests on assumptions about how Galilean transformations act on the wavefunction that are unwarranted. My discussion has larger morals about the phys- ical significance of certain mathematical results in non-orthodox interpretations of quantum mechanics.

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.

Local versions of the (special) principle of relativity say that if the same type of experiment is conducted in two isolated, unaccelerated laboratories, then the outcomes of those experiments must be the same. Global versions of the principle say that if you take a physically possible world and boost the entire material content of that world, you get another physically possible world. Some authors say that the local and the global principles are logically independent, and that the local version is more important. These authors are wrong. I argue that the global version entails the local version, and discuss why a counterexample to this entailment offered by Tim Budden fails

There are lots of arguments for, or justifications of, mathematical theorems that make use of principles from physics. Do any of these constitute explanations? On the one hand, physical principles do not seem like they should be explanatorily relevant; on the other, some particular examples of physical justifications do look explanatory. In this article, I defend the idea that physical justifications can and do explain mathematical facts. 1 Physical Arguments for Mathematical Truths2 Preview3 Mathematical Facts4 Purity5 Doubts about Purity: I6 Doubts about Purity: II7 How Physical Arguments Might Explain: I8 How Physical Arguments Might Explain: II9 Conclusion

Sklar ([1974]) claimed that relationalism about ontology-the doctrine that space and time do not exist-is compatible with Newtonian mechanics. To defend this claim he sketched a relationalist interpretation of Newtonian mechanics. In his interpretation, absolute acceleration is a fundamental, intrinsic property of material bodies; that a body undergoes absolute acceleration does not entail that space and time exist. But Sklar left his proposal as just a sketch; his defense of relationalism succeeds only if the sketch can be filled in. I argue that this cannot be done. There can be no (relationalist) dynamical laws of motion based on Sklar's proposal that capture the content of Newton's theory. So relationalists must look elsewhere for a relationalist interpretation of Newtonian mechanics

What does the passage of time consist in? There are some suggestive metaphors. âEvents approach us, pass us, and recede from us, like sticks and leaves floating on the river of time.â âWe are moving from the past into the future, like ships sailing into an unknown ocean.â There is surely something right and deep about these metaphors. But how close are they to the literal truth? In this book Bradford Skow argues that they are far from the literal truth. Skowâs argument takes the form of a defense of the block universe theory of time, a theory that, in many ways, treats time as a dimension of reality that closely resembles the three dimensions of space. Opposed to the block universe theory of time are theories that take the metaphors more seriously: presentism, the moving spotlight theory, the growing block theory, and the branching time theory. These are theories of ârobustâ passage of time, or âobjective becoming.â Skow argues that the best of these theories, the block universe theoryâs most worthy opponent, is the moving spotlight theory, the theory that says that âpresentnessâ moves along the series of times from the past into the future. Skow defends the moving spotlight theory against the objection that it is inconsistent, and the objection that it cannot answer the question of how fast time passes. He also defends it against the objection that it is incompatible with Einsteinâs theory of relativity. Skow proposes several ways in which the moving spotlight theory may be made compatible with the theory of relativity. Still, this book is ultimately a defense of the block universe theory, not of the moving spotlight theory. Skow holds that the best arguments against the block universe theory, and for the moving spotlight theory, start from the idea that, somehow, the passage of time is given to us in experience. Skow discusses several different arguments that start from this idea, and argues that they all fail.