Storrs McCall

A theory of temporal passage is put forward which is "objective" in the sense that time flow characterizes the universe independently of the existence of conscious beings. The theory differs from Grunbaum's "mind-dependence" theory, and is designed to avoid Grunbaum's criticisms of an earlier theory of Reichenbach's. The representation of temporal becoming is accomplished by the introduction of indeterministic universe-models; each model representing the universe at a time. The models depict the past as a single four-dimensional manifold, and the future as a branched structure of such manifolds. Time flow is relativistic in that it manifests itself in a frame-dependent (but not observer-dependent) way. The indeterministic character of the universe-models is mirrored in a "temporal" theory of truth which rejects the principle of bivalence, and suitable semantics are provided for this theory. Finally, an account of physical law is given which defines it in terms of physical possibility, rather than vice versa

David Lewis, following in the tradition of Broad, Quine and Goodman, says that change in an object X consists in X's being temporally extended and having qualitatively different temporal parts. Analogously, change in a spatially extended object such as a road consists in its having different spatial parts . The alternative to this view is that ordinary objects undergo temporal change in virtue of having different intrinsic non-relational properties at different times. They endure, remaining the same object throughout change, whereas Lewis's temporally extended 4D objects perdure.It is impossible to come down on one side or the other of the endurance/perdurance debate without a clear and unambiguous understanding of what ‘endurance’ is. ‘Perdurance’ is clear enough. Every 4D object of non-zero temporal thickness perdures simply by having temporal extension, i.e. by having different temporal parts, or stages, at different times. But Lewis muddies the waters by giving a confused and ultimately untenable definition of endurance.His first step is to cover both perduring and enduring by offering the neutral word persist. ‘Let us say that something persists iff, somehow or other, it exists at various times’ . Something then perdures if it persists by having different temporal parts at different times, no one part being wholly present at more than one time. In contrast, a thing endures if it persists by being wholly present at more than one …

The thesis of 3D/4D equivalence states that every three-dimensional description of the world is translatable without remainder into a four-dimensional description, and vice versa. In representing an object in 3D or in 4D terms we are giving alternative descriptions of one and the same thing, and debates over whether the ontology of the physical world is "really" 3D or 4D are pointless. The twins paradox is shown to rest, in relativistic 4D geometry, on a reversed law of triangle inequality. But considering the twins as 3D beings who age through time, the paradox implies that time passes at different rates in different reference frames, and therefore that the concept of a single global or Absolute time is unsustainable

Over the last 25 years, experimental findings published by Benjamin Libet have indicated that conscious acts of will are preceded by a characteristic kind of brain event of which the agent is not conscious. It, Libet says, rather than the will, is what causes actions. His discoveries, if correct, would seem to imply that the notion of a free, conscious will is an illusion, and that actions are initiated by neural processes not under conscious control. In what follows it is argued that Libet’s conclusion is incorrect, and that other evidence points to the essential causal role of consciousness in voluntary action.

In his paper ‘‘Bad luck once again’’ Neil Levy attacks our proof of the consistency of libertarianism by reiterating a time-worn compatibilist complaint.1 This is, that what is not determined must be due to chance. If A has a choice of X or Y, neither X nor Y being causally determined, then if A chooses X it can only be by chance, never for a reason. The only ‘‘reason’’ that could explain the choice of X over Y would have to be a causally sufficient reason, which would rule out A’s having a genuine choice in the first place. Either X is causally necessitated or X is realized by sheer luck. But that these are the only alternatives is untrue. The exercise of deliberative reason opens the way between the Scylla of causal necessitation and the Charybdis of chance, as we shall try to make clear. The central core of Levy’s argument is that any attempt to give a reasons-based explanation of a contrastive fact must fail. A contrastive fact is a fact of the kind ‘‘Jane decides to vacation in Hawaii rather than Colorado,’’ or ‘‘Jane assigns a greater weight to surfing that to white-water rafting.’’ In the last three paragraphs of his paper Levy argues that Jane’s assigning more weight to surfing than to rafting cannot be a reasons-based assignment, because, as he puts it, ‘‘the reasons that would explain the weighting are the weighted reasons themselves.’’ Similarly, prior to making her Hawaii⁄ Colorado decision, Jane has..

The aim of the paper is to prove the consistency of libertarianism. We examine the example of Jane, who deliberates at length over whether to vacation in Colorado (C) or Hawaii (H), weighing the costs and benefits, consulting travel brochures, etc. Underlying phenomenological deliberation is an indeterministic neural process in which nonactual motor neural states n(C) and n(H) corresponding to alternatives C and H remain physically possible up until the moment of decision. The neurophysiological probabilities pr(n(C)) and pr(n(H)) evolve continuously according to the different weights Jane's judgement attaches to C and H at different times during the deliberation. The overall process is indeterministic, since Jane's exact judgemental weighting would vary slightly were the process to be repeated from the same initial conditions. The weighting is however rational, and entirely under Jane's control. This controlled, rational, indeterministic process shows that libertarianism is a consistent philosophical thesis

Combining quantum mechanics with special relativity requires (i) that a spacetime representation of quantum states be found; (ii) that such states, represented as extended along equal-time hyperplanes, be invariant when transformed from one frame to another; and (iii) that collapses of states be instantaneous in every frame. These requirements are met using branching spacetime, in which probabilities of outcomes are represented by the numerical proportions of branches on which the outcomes occur. Quantum states of systems are then identified with the probability values, built into spacetime along spacelike hypersurfaces, of all possible outcomes of all possible tests to which the systems can be subjected

A common criticism of free will or origination theories is that if what we do is not the result of an unbroken sequence of causes and effects, then it must to some degree be the product of chance. But in what sense can a chance act be intentional or deliberate, in what sense can it be based on reasons, and in what sense can a person be held responsible for it? If free and responsible action is incompatible with determinism, must it not equally well be incompatible with indeterminism? Professor McCall says no. He argues that a new idea, that of a controlled indeterministic process, resolves a variety of classical dilemmas and opens the way to a new understanding of the relationship between actions, reasons, causes, and responsibility. Does he succeed? All of this, like a related line of argument by Professor McCann to which you can turn, is a long way from what seems to me the continuing arguableness of determinism and the unavoidableness of the proposition that both incompatibilism and compatibilism about freedom are false. But we all need to remember, with Cromwell, in our own bowels if not by those of Christ, that we may be mistaken. I guess that given the proportion of false to true views in the world, we need to remember it is arguable that we are more likely to be mistaken.

We all make decisions, sometimes dozens in the course of a day. This paper is about what is involved in this activity. It's my contention that the ability to deliberate, to weigh different courses of action, and then to decide on one of them, is a distinctively human activity, or at least an activity which sets man and the higher animals apart from other creatures. It is as much decisio as ratio that constitutes the distinguishing mark of human beings. Homo may not always be rationalis, but he is always decidens.The paper is about practical decision, although there is also another important kind of decision that I won't discuss, namely cognitive decision. The difference is roughly that which distinguishes the function of a jury from that of a judge, at least in jury trials. The jury's job is to arrive at an answer to the question: guilty or not guilty? This is a cognitive decision, a decision that, on the basis of the evidence, such-and-such is the case. The judge, apprized of the jury's cognitive decision, makes the practical decision to sentence the guilty party to 20 years. On some other occasion, I hope to be able to say something about cognitive decision, as well as about a third kind of decision named value decision.

Relative to any point in time, how many possible futures are there? For example, it may rain tomorrow, or again it may not. So it would appear that relative to today, there are at least two possible futures, one involving rain tomorrow and the other not. Of course only one of these two future states of affairs will take place, and in that sense there is only one actual future, though there may be many possible futures. The only hypothesis under which there is, for every instant in time, only one possible future, is the hypothesis of universal Laplacean determinism, and this hypothesis has had little to recommend it since the advent of quantum physics. Furthermore, although among the many possible futures relative to any given moment in time there is only one which will become actual, no distinguishing mark separates this one from its fellows at the given moment. So it would appear that what confronts the world at each moment in time is an undifferentiated multiplicity of possible futures. But this multiplicity, though at first sight admittedly frightening in its implications, may be put to good philosophical use: as will be seen it yields natural and convincing definitions of the notions of physical necessity and possibility. On the other hand, alternative definitions of these notions are obtainable which do not make use of the manifold of possible futures, and these also will be presented. The paper will be in two parts, the first dealing with the concepts of physical possibility and necessity, and the second presenting a formal calculus of necessary and sufficient conditions in which the physical modalities find their place.

The basis of a rigorous formal axiomatization of quantum mechanics is constructed, built upon Dirac's bra-ket notation. The system is three-sorted, with separate variables for scalars, vectors and operators. First-order quantification over all three types of variable is permitted. Economy in the axioms is effected by, e.g., assigning a single logical function * to transform (i) a scalar into its complex conjugate, (ii) a ket vector into a bra and a bra into a ket, (iii) an operator into its adjoint. The system is accompanied by a formal semantics. Further papers will deal with vector subspaces and projection operators, operators with continuous spectra, tensor products, observables, and quantum mechanical probabilities