Online research in philosophy

Time, Change and Freedom is the first introduction to metaphysics that uses the idea of time as a unifying principle. Time is used to relate the many issues involved in the complex study of metaphysics. Sections of the book are written in dialogue form which allows the reader to question the theories while they read and have those queries answered in the text. In addition, the authors provide glossaries of key terms as well as recommendations for further reading at the conclusion of each chapter. Quentin Smith and L. Nathan Oaklander examine the tensions between determinism and freedom, temporality and historical change as well as an array of other issues fundamental to introductory metaphysics.

Recent developments in quantum theory have focused attention on fundamental questions, in particular on whether it might be necessary to modify quantum mechanics to reconcile quantum gravity and general relativity. This book is based on a conference held in Oxford in the spring of 1984 to discuss quantum gravity. It brings together contributors who examine different aspects of the problem, including the experimental support for quantum mechanics, its strange and apparently paradoxical features, its underlying philosophy, and possible modifications to the theory.

Many physicists believe that time constitutes a serious problem in quantum mechanics. We show nevertheless that quantum mechanics does not involve a special problem for time, and that there is no fundamental asymmetry between space and time in quantum mechanics over and above the asymmetry that already exists in classical physics. The apparent problem of time arises when the time parameter is put on a par with dynamical position variables rather than with the coordinates of space. The commutation relations and uncertainty relations are generally considered to embody the essential content of elementary quantum mechanics, but the traditional mathematical expression of the uncertainty principle it shown to be quite unsatisfactory. It is the total energy that decrees whether or not the time variables of a system can be sharply determined.

In Book IV, Chapter 11 of the Physics, Aristotle claims that ‘the before and after’ exists in time because it also exists in change, and it exists in change because it also exists in magnitude, and, further, that ‘time follows change’ and ‘change follows magnitude’.1 This is usually taken to mean that moments of time correspond to momentary stages of changes, and that momentary stages of changes correspond to points in magnitudes, so that time derives its ‘before and after’ from that of change, and change from that of magnitude.2 But this is widely thought to land Aristotle in the following diffi culty: If Socrates walks between points A and C, for instance, he can either proceed from point A to point..

In economics, the concept of time discounting introduces weights on future goods to make these less valuable. Yet, both the conceptual motivation for time discounting and its specic functional form remain contested. To address these problems, this paper provides a measurement-theoretic framework of representation for time discounting. The representation theorem characterises time discounting factors by representations of time dierences. This general result can be interpreted with existing theories of time discounting to clarify their formal and conceptual assumptions. It also provides a conceptually neutral framework for comparing the descriptive and normative merits of those theories.

The advent of the 1905 theory of relativity is rightly considered as a breakthrough moment in the history of physics; in particular. it is widely accepted that it brought a new conception of space and time. The purpose of this work is to reevaluate to what point and in what sense can we consider that the conception of space and time went through a transformation when going from Newtonian mechanics to the theory of relativity.

The problem of change plays a central role in the metaphysics of time and material objects, and whoever does best in solving this problem has a leg up when it comes to choosing a metaphysics of time and material objects. But whether this central role of the problem of change in metaphysics is legitimate is not at all clear. This is so in part since it is not clear what the problem of change is, and why it is a problem in metaphysics. We will investigate what metaphysical problem the problem of change might be, and how it relates to various other problems related to change that are studied in the empirical sciences. The problem of change can thus be a case study of what makes a problem a metaphysical one and how metaphysics relates to other parts of inquiry. We conclude that the central role the problem of change is given in the contemporary metaphysics of time is not justified.

The concept of time discounting introduces weights on future goods to make these less valu- able. Famously, both the specic functional form of time discounting and its normative sta- tus are contested. To address these problems, this paper provides a measurement-theoretic framework of representation for time discounting. The general representation theorem char- acterises time discounting factors as ratio-scale representations of dierences in temporally extended prospects. This framework of representation is used to reconsider interpretations of time discounting factors such as time preferences, uncertainty and preference change. It also allows to compare these interpretations with regards to their normative appeal, the kinds of reductionism regarding time and preference they imply and the specic functional form of time discounting they suggest. Farther, multiple-self interpretations of decision-makers become available, such that a time discounting factor represents the degree of connectedness between temporal selves in a person.

This is a comprehensive book on the philosophy of time. Leading philosophers discuss the metaphysics of time, our experience and representation of time, the role of time in ethics and action, and philosophical issues in the sciences of time, especially quantum mechanics and relativity theory.

Physicists who work on canonical quantum gravity will sometimes remark that the general covariance of general relativity is responsible for many of the thorniest technical and conceptual problems in their field.1 In particular, it is sometimes alleged that one can trace to this single source a variety of deep puzzles about the nature of time in quantum gravity, deep disagreements surrounding the notion of ‘observable’ in classical and quantum gravity, and deep questions about the nature of the existence of spacetime in general relativity. Philosophers who think about these things are sometimes skeptical about such claims. We have all learned that Kretschmann was quite correct to urge against Einstein that the “General Theory of Relativity” was no such thing, since any theory could be cast in a generally covariant form, and hence the general covariance of general relativity could not have any physical content, let alone bear the kind of weight that Einstein expected it to.2 Friedman’s assessment is widely accepted: “As Kretschmann first pointed out in 1917, the principle of general covariance has no physical content whatever: it specifies no particular physical theory; rather, it merely expresses our commitment to a certain style of formulating physical theories” (1984, p. 44). Such considerations suggest that general covariance, as a technically crucial but physically contentless feature of general relativity, simply cannot be the source of any significant conceptual or physical problems.3 Physicists are, of course, conscious of the weight of Kretschmann’s points against Einstein. Yet they are considerably more ambivalent than their philosophical colleagues. Consider Kuchaˇr’s conclusion at the end of a discussion of this topic.