A reply to a comment by Paul Tappenden (BJPS 59 (2008) pp. 307-314) on S. Saunders and D. Wallace, "Branching and Uncertainty" (BJPS 59 (2008) pp. 298-306).

Particle indistinguishability has always been considered a purely quantum mechanical concept. In parallel, indistinguishable particles have been thought to be entities that are not properly speaking objects at all. I argue, to the contrary, that the concept can equally be applied to classical particles, and that in either case particles may (with certain exceptions) be counted as objects even though they are indistinguishable. The exceptions are elementary bosons (for example photons).

Ces études débordent le problème du temps chez les Stoïciens et se proposent d’établir que cette question, en apparence modeste, permet d’éclairer, et en même temps commande l’ensemble du système.Au premier abord en effet, la théorie du temps se présente comme une simple section d’un chapitre de la Physique, celui qui traite des Incorporels. Mais déjà la simple interprétation des textes transmis fait voir que cette théorie tient étroitement à d’autres théories, comme celle des incorporels en général, des catégories, de (...) la substance. Abordant ensuite les thèses majeures de la logique et de l’éthique, on s’aperçoit qu’à leur tour elles sont solidaires de la conception du temps qui, dans bien des cas, fait évanouir leur apparence de paradoxe. A cela même, il n’y a rien d’étrange, si l’on se souvient que le stoïcisme, plus que tout autre philosophie antique, constitue un système cohérent. Mais plus particulièrement, le problème du temps a dû former comme le noeud de la réflexion stoïcienne qui vise, contre les lourdes autorités de Platon et d’Aristote, à rétablir dans sa réalité et dans sa dignité, le concret, le sensible, disqualifié comme « sujet à la génération et à la corruption », c’est-à-dire, en un mot, comme « l’être dans le temps ». (shrink)

The paper defends a view of structural realism similar to that of French and Ladyman, although it differs from theirs in an important respect: I do not take indistinguishabiity of particles in quantum mechanics to have the significance they think it has. It also differs from Cao's view of structural realism, criticized in my "Critical Notice: Cao's `The Conceptual Development of 20th Century Field Theories".

I show that frequentism, as an explanation of probability in classical statistical mechanics, can be extended in a natural way to a decoherent quantum history space, the analogue of a classical phase space. The result is a form of finite frequentism, in which Gibbs’ concept of an infinite ensemble of gases is replaced by the quantum state expressed as a superposition of a finite number of decohering microstates. It is a form of finite and actual frequentism (as opposed to hypothetical (...) frequentism) insofar as all the microstates exist, in keeping with the decoherence-based Everett interpretation, and some versions of pilot-wave theory. (shrink)

Category Theory has developed rapidly. This book aims to present those ideas and methods which can now be effectively used by Mathe­ maticians working in a variety of other fields of Mathematical research. This occurs at several levels. On the first level, categories provide a convenient conceptual language, based on the notions of category, functor, natural transformation, contravariance, and functor category. These notions are presented, with appropriate examples, in Chapters I and II. Next comes the fundamental idea of an adjoint (...) pair of functors. This appears in many substantially equivalent forms: That of universal construction, that of direct and inverse limit, and that of pairs offunctors with a natural isomorphism between corresponding sets of arrows. All these forms, with their interrelations, are examined in Chapters III to V. The slogan is "Adjoint functors arise everywhere". Alternatively, the fundamental notion of category theory is that of a monoid -a set with a binary operation of multiplication which is associative and which has a unit; a category itself can be regarded as a sort of general­ ized monoid. Chapters VI and VII explore this notion and its generaliza­ tions. Its close connection to pairs of adjoint functors illuminates the ideas of universal algebra and culminates in Beck's theorem characterizing categories of algebras; on the other hand, categories with a monoidal structure lead inter alia to the study of more convenient categories of topological spaces. (shrink)

We demonstrate that the quantum-mechanical description of composite physical systems of an arbitrary number of similar fermions in all their admissible states, mixed or pure, for all finite-dimensional Hilbert spaces, is not in conflict with Leibniz's Principle of the Identity of Indiscernibles (PII). We discern the fermions by means of physically meaningful, permutation-invariant categorical relations, i.e. relations independent of the quantum-mechanical probabilities. If, indeed, probabilistic relations are permitted as well, we argue that similar bosons can also be discerned in all (...) their admissible states; but their categorical discernibility turns out to be a state-dependent matter. In all demonstrated cases of discernibility, the fermions and the bosons are discerned (i) with only minimal assumptions on the interpretation of quantum mechanics; (ii) without appealing to metaphysical notions, such as Scotusian haecceitas, Lockean substrata, Postian transcendental individuality or Adamsian primitive thisness; and (iii) without revising the general framework of classical elementary predicate logic and standard set theory, thus without revising standard mathematics. This confutes: (a) the currently dominant view that, provided (i) and (ii), the quantum-mechanical description of such composite physical systems always conflicts with PII; and (b) that if PII can be saved at all, the only way to do it is by adopting one or other of the thick metaphysical notions mentioned above. Among the most general and influential arguments for the currently dominant view are those due to Schrodinger, Margenau, Cortes, Dalla Chiara, Di Francia, Redhead, French, Teller, Butterfield, Giuntini, Mittelstaedt, Castellani, Krause and Huggett. We review them succinctly and critically as well as related arguments by van Fraassen and Massimi. (shrink)

What would it mean to apply quantum theory, without restriction and without involving any notion of measurement and state reduction, to the whole universe? What would realism about the quantum state then imply? This book brings together an illustrious team of philosophers and physicists to debate these questions. The contributors broadly agree on the need, or aspiration, for a realist theory that unites micro- and macro-worlds. But they disagree on what this implies. Some argue that if unitary quantum evolution has (...) unrestricted application, and if the quantum state is taken to be something physically real, then this universe emerges from the quantum state as one of countless others, constantly branching in time, all of which are real. The result, they argue, is many worlds quantum theory, also known as the Everett interpretation of quantum mechanics. No other realist interpretation of unitary quantum theory has ever been found. Others argue in reply that this picture of many worlds is in no sense inherent to quantum theory, or fails to make physical sense, or is scientifically inadequate. The stuff of these worlds, what they are made of, is never adequately explained, nor are the worlds precisely defined; ordinary ideas about time and identity over time are compromised; no satisfactory role or substitute for probability can be found in many worlds theories; they can't explain experimental data; anyway, there are attractive realist alternatives to many worlds. Twenty original essays, accompanied by commentaries and discussions, examine these claims and counterclaims in depth. They consider questions of ontology - the existence of worlds; probability - whether and how probability can be related to the branching structure of the quantum state; alternatives to many worlds - whether there are one-world realist interpretations of quantum theory that leave quantum dynamics unchanged; and open questions even given many worlds, including the multiverse concept as it has arisen elsewhere in modern cosmology. A comprehensive introduction lays out the main arguments of the book, which provides a state-of-the-art guide to many worlds quantum theory and its problems. (shrink)

Douglas Diekema influentially argues that interference with parental decisions is not in fact guided by the child’s best interests, but rather by a more permissive standard, which he calls the harm principle. This article first seeks to clarify this alternative position and defend it against certain existing criticisms, before offering a new criticism and alternative. This ‘harm principle’ has been criticized for (i) lack of adequate moral grounding, and (ii) being as indeterminate as the best interest standard that it seeks (...) to replace. I argue that these are not serious problems. I take Diekema’s negative point to be right—our actual standard for intervention is not literally the best interests of the child—but I disagree with his proposed replacement. First, Diekema’s proposed harm threshold should be more carefully distinguished from Mill’s harm principle. Second, there is no reason to assume that the standard for permissible intervention coincides with the threshold for harm (or serious harm). Thus, I propose that the best alternative to the best interests standard is not a harm principle, but rather a sufficiency threshold between adequate (or ‘good enough’) and inadequate (or ‘substandard’) parenting. (shrink)

A number of authors criticise opt-out (or ‘deemed consent’) systems for failing to secure valid consent to organ donation. Further, several suggest that mandated choice offers a more ethical alternative. This article responds to criticisms that opt-out does not secure informed consent. If we assume current (low) levels of public awareness, then the explicit consent secured under mandated choice will not be informed either. Conversely, a mandated choice policy might be justifiable if accompanied by a significant public education campaign. However, (...) if this entitles us to assume that members of the public are informed, then an opt-out system would also be justified in the same circumstances. The alleged advantages of mandated choice seem to rest on an unfair comparison, between mandated choice with a public education campaign and an opt-out system without one. While it may be that some countries with opt-out systems should do more to inform their publics, I see no reason to assume that this cannot be done. Indeed, advocates of mandated choice seem committed to thinking it possible to raise awareness. If opt-out systems adopt the same methods, such as writing to every individual, this should also address concerns about whether consent is informed. (shrink)

Divine Action and Modern Science considers the relationship between the natural sciences and the concept of God acting in the world. Nicholas Saunders examines the Biblical motivations for asserting a continuing notion of divine action and identifies several different theological approaches to the problem. He considers their theoretical relationships with the laws of nature, indeterminism, and probabilistic causation. His book then embarks on a radical critique of current attempts to reconcile special divine action with quantum theory, chaos theory and (...) quantum chaos. As well as considering the implications of these problems for common interpretations of divine action, Saunders also surveys and codifies the many different theological, philosophical and scientific responses to divine action. The conclusion reached is that we are still far from a satisfactory account of how God might act in a manner that is consonant with modern science despite the copious recent scholarship in this area. (shrink)

But this picture of a ‘block universe’, composed of a timeless web of ‘world-lines’ in a four-dimensional space, however strongly suggested by the theory of relativity, is a piece of gratuitous metaphysics. Since the concept of change, of something happening, is an inseparable component of the common-sense concept of time and a necessary component of the scientist's view of reality, it is quite out of the question that theoretical physics should require us to hold the Eleatic view that nothing happens (...) in ‘the objective world’. Here, as so often in the philosophy of science, a useful limitation in the form of representation is mistaken for a deficiency of the universe. (shrink)

Philosophers in China during the Warring States period generally saw themselves as investigators into the Dao—the uniquely authoritative Way to live and to flourish. Certain voices found in the Zhuangzi, however, offer a radical response to this project by rejecting the premise that there exists such a uniquely authoritative Dao. Instead, they argue that there exist myriad, diverse dao, none of which has absolute moral authority. Yet the very texts that undermine the idea of an authoritative Dao simultaneously make positive (...) ethical suggestions regarding how to live and flourish. In this paper I explore texts in the Zhuangzi that discuss the diversity of dao and sagely flourishing, and I argue that these two themes come together to form the basis of a comprehensive ethical view that I call Zhuangist pluralism. (shrink)

Some health-care institutions have ethics committees. The experience of the Ethical Issues Committee at the Royal College of Physicians is described. Ethics committees in institutions may be reactive or creative, must determine an agenda and must deal with dissent.

Informed by behavioral science research, recent defenses of paternalism point to people’s need for help in making and carrying out good decisions. Authors in this literature typically focus on defending paternalist policies against objections that frame them as threats to autonomy. But they often neglect a second category of objections to paternalism. Paternalism expresses disrespect not only for the target’s autonomy but also for her equal status. I argue that this second kind of wrong is more independent of autonomy-based objections (...) than has been recognized. Therefore, we need to evaluate paternalism in two dimensions, rather than treating egalitarian objections as a mere supplement to autonomy concerns. This allows us to see why welfare paternalism can be objectionable even when choices are not significantly constrained or when the choices at stake are relatively trivial. The barrier to justifiable welfare paternalist policies has less to do with the specific techniques of influence adopted than with their asymmetrical distribution and the inegalitarian structures through which they are delivered. (shrink)

It is widely accepted that the notion of an inertial frame is central to Newtonian mechanics and that the correct space-time structure underlying Newton’s methods in Principia is neo-Newtonian or Galilean space-time. I argue to the contrary that inertial frames are not needed in Newton’s theory of motion, and that the right space-time structure for Newton’s Principia requires the notion of parallelism of spatial directions at different times and nothing more. Only relative motions are definable in this framework, never absolute (...) ones. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy's Role in Psychopathology Back to Jaspers and an Appeal to Grow PracticalThe author reports no conflicts of interest.In "Philosophy's role in theorizing psychopathology," Gibson presents a defense of the continued relevance of philosophy to psychopathology, and a non-exhaustive framework for the role of philosophy in this domain (Gibson, 2024). I find it hard to disagree that psychopathology is soaked in philosophy from its origins, and that to try (...) and dry it out would be both unwise and impossible.In this commentary, I go back to Karl Jaspers' account of the role of philosophy in his General Psychopathology. In doing so, I do not find that Gibson adds anything new, but instead gives us a well-illustrated reminder that philosophy "is operative within every living science" (Jaspers, 1997, p. 770).Situated Psychopathological TheorizingGibson addresses a broad 'we' who might be engaged with psychopathological theorizing. This seems to encompass three main settings, from which examples are drawn.1. Everyday and regulative social practices (ordinary and legal setting).2. Empirically driven disciplines which work with psychopathological constructs (academic setting).3. Psychiatry and psychotherapy (clinical setting).In my view, it is a mistake not to map the terrain where psychopathological theorizing is situated. In each setting psychopathological theorizing has its own set of aims and constraints. In the ordinary setting, the aim might be to know whether to blame a loved one for their action. In the legal setting it might be to decide whether treatment or punishment is appropriate. In the clinical setting, the aim is usually a therapeutic assessment, and moral stance taking is often best kept at bay. In the academic setting, we might want to ensure our concepts are reliable and valid, opening them up to investigation using objective scientific methods. [End Page 13]Beyond what can be said in the most general terms, the role of philosophy will look different in these different situations.Understanding Is Not (Just) a Philosophical ToolUnderstanding is a mode of knowing that is concerned with the particular, rather than the general, and accessed inter-relationally, relying on tacit knowledge and empathetic imagination. Gibson introduces the concept as an elementary form of social intuition, used in ordinary life to make sense of social relations and other people's behaviors and reactions. I agree with Gibson, drawing on Strawson, that Understanding is a mode of knowledge that involves the subject of enquiry as a participant (Strawson, 1982). There is a moral imperative to take this stance, which drives us to value the expansion of what we are able to understand of other people's mental states. This at least partly motivates the agenda when we theorize about psychopathology.At times throughout his argument, Gibson seems to be arguing for the role of Understanding in psychopathological theorizing, in place of his explicit aim of arguing for the role of philosophy. However it is not at all clear that this replacement can be made. Accepting the picture drawn, Understanding is not any more the expertise or domain of the philosopher than the author, police officer, or sociologist. We are surely not meant to take Understanding as a uniquely philosophical tool, but rather a mode of knowing available to all social agents, integral to social reasoning in ordinary life and in the human studies.What philosophy can distinctively do is point to and defend the existence of forms of intersubjective and tacit knowledge within human studies such as psychopathology. For Jaspers, Understanding can be a scientific tool, albeit one that reminds us that knowledge in psychopathology is not all of one kind. One role for philosophy therefore is to help us to "distinguish the different modes of knowing," so that we might "order knowledge into a comprehensive whole" (Jaspers, 1997, p. 769). This is akin to the 'synthetic' role that Gibson proposes.Philosophy and ScienceJaspers defines scientific knowledge broadly as knowledge with "general validity, convincing insights (which can be proved), clarity of method, and the possibility for a meaningful discussion" (Jaspers, 1997, p. 768).We do not get such a definition from Gibson, but in the sections of... (shrink)

The Gibbs Paradox is essentially a set of open questions as to how sameness of gases or fluids are to be treated in thermodynamics and statistical mechanics. They have a variety of answers, some restricted to quantum theory, some to classical theory. The solution offered here applies to both in equal measure, and is based on the concept of particle indistinguishability. Correctly understood, it is the elimination of sequence position as a labelling device, where sequences enter at the level of (...) the tensor product of one-particle state spaces. In both cases it amounts to passing to the quotient space under permutations. ‘Distinguishability’, in the sense in which it is usually used in classical statistical mechanics, is a mathematically convenient, but physically muddled, fiction. (shrink)

Following Lewis, it is widely held that branching worlds differ in important ways from diverging worlds. There is, however, a simple and natural semantics under which ordinary sentences uttered in branching worlds have much the same truth values as they conventionally have in diverging worlds. Under this semantics, whether branching or diverging, speakers cannot say in advance which branch or world is theirs. They are uncertain as to the outcome. This same semantics ensures the truth of utterances typically made about (...) quantum mechanical contingencies, including statements of uncertainty, if the Everett interpretation of quantum mechanics is true. The ‘incoherence problem’ of the Everett interpretation, that it can give no meaning to the notion of uncertainty, is thereby solved. IntroductionMetaphysicsPersonal fissionBranching worldsPhysicsObjections. (shrink)

Bohr’s interpretation of quantum mechanics has been criticized as incoherent and opportunistic, and based on doubtful philosophical premises. If so Bohr’s influence, in the pre-war period of 1927–1939, is the harder to explain, and the acceptance of his approach to quantum mechanics over de Broglie’s had no reasonable foundation. But Bohr’s interpretation changed little from the time of its first appearance, and stood independent of any philosophical presuppositions. The principle of complementarity is itself best read as a conjecture of unusually (...) wide scope, on the nature and future course of explanations in the sciences (and not only the physical sciences). If it must be judged a failure today, it is not because of any internal inconsistency. (shrink)

The Politics is one of the most influential texts in the history of political thought, and it raises issues which still confront anyone who wants to think seriously about the ways in which human societies are organized and governed. The work of one of the world's greatest philosophers, it draws on Aristotle's own great knowledge of the political and constitutional affairs of the Greek cities. By examining the way societies are run - from households to city states - Aristotle establishes (...) how successful constitutions can best be initiated and upheld. For this edition Sir Ernest Barker's fine translation, which has been widely used for nearly half a century, has been extensively revised to meet the needs of the modern reader. The accessible introduction and clear notes by R F Stalley examine the historical and philosophical background of the work and discuss its significance for modern political thought. (shrink)

A variety of ideas arising in decoherence theory, and in the ongoing debate over Everett's relative-state theory, can be linked to issues in relativity theory and the philosophy of time, specifically the relational theory of tense and of identity over time. These have been systematically presented in companion papers (Saunders 1995; 1996a); in what follows we shall consider the same circle of ideas, but specifically in relation to the interpretation of probability, and its identification with relations in the Hilbert (...) Space norm. The familiar objection that Everett's approach yields probabilities different from quantum mechanics is easily dealt with. The more fundamental question is how to interpret these probabilities consistent with the relational theory of change, and the relational theory of identity over time. I shall show that the relational theory needs nothing more than the physical, minimal criterion of identity as defined by Everett's theory, and that this can be transparently interpreted in terms of the ordinary notion of the chance occurrence of an event, as witnessed in the present. It is in this sense that the theory has empirical content. (shrink)

In this paper, we draw attention to several important tensions between Kant’s account of moral education and his commitment to transcendental idealism. Our main claim is that, in locating freedom outside of space and time, transcendental idealism makes it difficult for Kant to both provide an explanation of how moral education occurs, but also to confirm that his own account actually works. Having laid out these problems, we then offer a response on Kant’s behalf. We argue that, while it might (...) look like Kant has to abandon his commitment to either moral education or transcendental idealism, there is a way in which he can maintain both. (shrink)

Chiara Cordelli’s The Privatized State offers a powerful critique of privatization and an inspiring vision of the kind of democratic governance that could secure citizens’ equal freedom. This essay raises questions about how Cordelli’s arguments apply in non-ideal theory. It asks whether her arguments about the illegitimacy of privatization provide us with adequate reasons to reject ongoing processes of privatization. It also queries some of her recommendations for how philanthropy should be practiced by individuals and incentivized by the state.

This paper defends an ‘opt-out’ scheme for organ procurement, by distinguishing this system from ‘presumed consent’ (which the author regards as an erroneous justification of it). It, first, stresses the moral importance of increasing the supply of organs and argues that making donation easier need not conflict with altruism. It then goes on to explore one way that donation can be increased, namely by adopting an opt-out system, in which cadaveric organs are used unless the deceased (or their family) registered (...) an objection. Such policies are often labelled ‘presumed consent’, but it is argued that critics are right to be sceptical of this idea—consent is shown to be an action, rather than a mental attitude, and thus not something that can be presumed. Either someone has consented or they have not, whatever their attitude to the use of their organs. Thankfully, an opt-out scheme need not rest on the presumption of consent. Actual consent can be given implicitly, by one's actions, so it is argued that the failure to register an objection (given certain background conditions) should itself be taken as sign of consent. Therefore, it is permissible to use the organs of someone who did not opt out, because they have—by their silence—actually consented. (shrink)

Fairness is a central, but under-theorized, notion in moral and political philosophy. This paper makes two contributions. Firstly, it criticizes Broome’s seminal account of fairness in Proc Aristotelian Soc 91:87–101, showing that there are problems with restricting fairness to a matter of relative satisfaction and holding that it does not itself require the satisfaction of the claims in question. Secondly, it considers the justification of lotteries to resolve cases of ties between competing claims, which Broome claims as support for his (...) theory, and contrasts random procedures to contests of skill, which may also be considered lotteries in a broader sense. I offer no alternative account of fairness of my own, but hope to point the way for future research on the nature of fairness. (shrink)

The concept of indistinguishable particles in quantum theory is fundamental to questions of ontology. All ordinary matter is made of electrons, protons, neutrons, and photons and they are all indistinguishable particles. Yet the concept itself has proved elusive, in part because of the interpretational difficulties that afflict quantum theory quite generally, and in part because the concept was so central to the discovery of the quantum itself, by Planck in 1900; it came encumbered with revolution. I offer a deflationary reading (...) of the concept ‘indistinguishable’ that is identical to Gibbs’ concept ‘generic phase’, save that it is defined for state spaces with only finitely-many states of bounded volume and energy. That, and that alone, makes for the difference between the quantum and Gibbs concepts of indistinguishability. This claim is heretical on several counts, but here we consider only the content of the claim itself, and its bearing on the early history of quantum theory rather than in relation to contemporary debates about particle indistinguishability and permutation symmetry. It powerfully illuminates that history. (shrink)

The problem of measurement is usually thought of as a problem of physics. Certainly the straightforward solutions modify or supplement the basic equations. One might instead conclude that theories are only instruments for coördinating observable phenomena, and perhaps that is what Bohr’s Copenhagen interpretation really comes down to. For most of us this sort of “philosophical” resolution of the problem of measurement is not acceptable.

The novel coronavirus (SARS-CoV-2) pandemic has refocused attention on the issue of mandatory vaccination. Some have suggested that vaccines ought to be mandatory, while others propose more moderate alternatives, such as incentives. This piece surveys a range of possible interventions, ranging from mandates through to education. All may have their place, depending on circumstances. However, it is worth clarifying the options available to policymakers, since there is sometimes confusion over whether a particular policy constitutes a mandate or not. Further, I (...) illustrate a different kind of alternative to mandatory vaccination. Rather than seeking less coercive alternatives to a mandate, we might instead employ an alternative mandate, which requires people to do something less than get vaccinated. For instance, we might merely require people to attend an appointment at a vaccine clinic. Whether this mandatory attendance policy is justified will depend on specific circumstances, but it represents another way to promote vaccination, without mandating it. In some cases, this may represent an appropriate balance between promoting public health goals and respecting individual liberty. (shrink)

State-reduction and the notion of actuality are compared to passage through time and the notion of the present; already in classical relativity the latter give rise to difficulties. The solution proposed here is to treat both tense and value-definiteness as relational properties or facts as relations; likewise the notions of change and probability. In both cases essential characteristics are absent: temporal relations are tenselessly true; probabilistic relations are deterministically true. The basic ideas go back to Everett, although the technical development (...) makes use of the decoherent histories theory of Griffiths, Omnès, and Gell-Mann and Hartle. Alternative interpretations of the decoherent histories framework are also considered. (shrink)

Proposals for increasing organ donation are often rejected as incompatible with altruistic motivation on the part of donors. This paper questions, on conceptual grounds, whether most organ donors really are altruistic. If we distinguish between altruism and solidarity – a more restricted form of other-concern, limited to members of a particular group – then most organ donors exhibit solidarity, rather than altruism. If organ donation really must be altruistic, then we have reasons to worry about the motives of existing donors. (...) However, I argue that altruism is not necessary, because organ donation supplies important goods, whatever the motivation, and we can reject certain dubious motivations, such as financial profit, without insisting on altruism.Once solidaristic donation is accepted, certain reforms for increasing donation rates seem permissible. This paper considers two proposals. Firstly, it has been suggested that registered donors should receive priority for transplants. While this proposal appears based on a solidaristic norm of reciprocity, it is argued that such a scheme would be undesirable, since non-donors may contribute to society in other ways. The second proposal is that donors should be able to direct their organs towards recipients that they feel solidarity with. This is often held to be inconsistent with altruistic motivation, but most donation is not entirely undirected in the first place (for instance, donor organs usually go to co-nationals). While allowing directed donation would create a number of practical problems, such as preventing discrimination, there appears to be no reason in principle to reject it. (shrink)

The vacuum is fast emerging as the central structure of modern physics. This collection brings together philosophically-minded specialists who engage these issues in the context of classical gravity, quantum electrodynamics, and the grand unification program. The vacuum emerges as the synthesis of concepts of space, time, and matter; in the context of relativity and the quantum this new synthesis represents a structure of the most intricate and novel complexity. This book is a work in modern metaphysics, in which the concepts (...) of substance and space interweave in the most intangible of forms, the background and context of our physical experience: vacuum, void, or nothingness. (shrink)