HOW TO PREDICT FUTURE DURATION FROM PRESENT AGE

The physicist J. Richard Gott has given an argument which, if good, allows one to make accurate predictions for the future longevity of a process, based solely on its present age. We show that there are problems with some of the details of Gott's argument, but we defend the core thesis: in many circumstances, the greater the present age of a process, the more likely a longer future duration.     

TIME TRAVEL WITHOUT CAUSAL LOOPS

It has sometimes been suggested that backwards time travel always incurs causal loops. I show that this is mistaken, by describing worlds where backwards time travel occurs and yet no causal loops occur. Arguments that backwards time travel can occur without causal loops have been given before in the literature, but I show that those arguments are unconvincing.     

Presentism and the objection from being-supervenience

In this paper, we show that presentism—the view that the way things are is the way things presently are—is not undermined by the objection from being-supervenience. This objection claims, roughly, that presentism has trouble accounting for the truth-value of past-tense claims. Our demonstration amounts to the articulation and defence of a novel version of presentism. This is brute past presentism, according to which the truth-value of past-tense claims is determined by the past understood as a fundamental aspect of reality different from things and how things are.     

McTaggart and Modern Physics

This paper delves into McTaggart’s metaphysical account of reality without time, and compares and contrasts McTaggart’s account with the account of reality given by modern physics. This comparison is of interest, because there are suggestions from contemporary physics that there is no time at the fundamental level. Physicists and philosophers of physics recognize that we do not have a good understanding of how the world could be such that time is unreal. I argue that, from the perspective of one who is trying to understand modern physics, McTaggart’s metaphysical views do provide some insight into how reality can be timeless at the fundamental level, but the insight that they provide is limited.     

Supererogatory Superluminality

We argue that any superluminal theory Tis empirically equivalent to a non-superluminaltheory T , with thefollowing constraints onT : T preservesthe spacetime intervals between events as entailedby T, T is naturalistic (as longas T is), and all the events which have causesaccording to T also have causes according toT. Tim Maudlin (1996) definesstandard interpretations of quantum mechanicsas interpretations `according to which there wasa unique set of outcomes in Aspect's laboratory,which outcomes occurred at spacelike separation, andMaudlin claims that standard interpretations must benon-local in the sense that there are superluminalinfluences. We show (even assuming Aspect's experimentis ideal) that Maudlin's claim is false.     

Wave Function Ontology

I argue that the wave function ontology for quantum mechanics is an undesirable ontology. This ontology holds that the fundamental space in which entities evolve is not three-dimensional, but instead 3N-dimensional, where N is the number of particles standardly thought to exist in three-dimensional space. I show that the state of three-dimensional objects does not supervene on the state of objects in 3N-dimensional space. I also show that the only way to guarantee the existence of the appropriate mental states in the wave function ontology has undesirable metaphysical baggage: either mind/body dualism is true, or circumstances which we take to be logically possible turn out to be logically impossible.While our theory can be extended formally in a logically consistent way by introducing the concept of a wave in a 3N-dimensional space, it is evident that this procedure is not really acceptable in a physical theory... (Bohm 1957, 117)     

The Doomsday Argument without Knowledge of Birth Rank

The Carter–Leslie doomsday argument can be given in a situation where you do not know your birth rank, even approximately. This gives support to the refutation of the doomsday argument based on the self–indication assumption 'Finding that you exist gives you reason to think that there are many observers'.