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)

It has been argued that nonreductive physicalism leads to epiphenominalism about mental properties: the view that mental events cannot cause behavioral effects by virtue of their mental properties. Recently, attempts have been made to develop accounts of causal relevance for irreducible properties to show that mental properties need not be epiphenomenal. In this paper, I primarily discuss the account of Frank Jackson and Philip Pettit. I show how it can be developed to meet several obvious objections and to capture our (...) intuitive conception of degrees of causal relevance. However, I argue that the account requires large-scale miraculous coincidence for there to be causally relevant mental properties. I also argue that the same problem arises for two apparently very different accounts of causal relevance. I suggest that this result does not show that these accounts, on appropriate readings, are false. Therefore, I tentatively conclude that we have reason to believe that irreducible mental properties are causally irrelevant. Moreover, given that there is at leastprima facie evidence that mental properties can be causally relevant, my conclusion casts doubt on nonreductive physicalist theories of mental properties. (shrink)

Jerry Fodor has defended the claim that psychological theories should appeal to narrow rather than wide intentional properties. One of his arguments relies upon the cross contexts test, a test that purports to determine whether two events have the same causally relevant properties. Critics have charged that this test is too weak, since it counts certain genuinely explanatory relational properties in science as being causally irrelevant. Further, it has been claimed, the test is insensitive to the fact that special scientific (...) laws allow for exceptions which do not undermine those laws. This paper refines the cross contexts test to meet these objections while still allowing it to play its role in Fodor. (shrink)

This dissertation is concerned with whether mental properties can be causally relevant to behavior, that is, whether a mental event can cause a piece of behavior by virtue of its mental properties. Since it seems that my behavior is not just a causal consequence of my beliefs and desires, but is caused by those beliefs and desires precisely because they are those beliefs and desires, an affirmative answer to this question is commonly taken to be required for a successful philosophical (...) defense of commonsense psychology. My discussion proceeds from two widely held, if controversial, views of the nature of mental properties, that they are irreducible to physical properties, and that they are relational/historical properties having components outside the head. I give separate arguments for the causal irrelevance of mental properties from each of these views. I then consider the implications of my views for commonsense psychology. I argue that it is possible to give a plausible account of rationalizing explanation of action without presupposing the causal relevance of the mental. Moreover, I argue that even if scientific psychology has reason to eschew causally irrelevant properties, it is nonetheless possible for scientific psychology to be said to have vindicated our common sense psychological practices. Thus, I defend the claim that causal relevance of the mental is in fact not necessary for a philosophical defense of commonsense psychology. (shrink)

Out of a concern to respect the naturalistic fallacy, Ruse (1986) argues for the possibility of causal, but not justificatory, explanations of morality in terms of evolutionary processes. In a discussion of Ruse's work, Rottschaefer and Martinsen (1990) claim that he erroneously limits the explanatory scope of evolutionary concepts, because he fails to see that one can have objective moral properties without committing either of two forms of the naturalistic fallacy, if one holds that moral properties supervene on non-moral properties. (...) In this short paper I argue that Rottschaefer and Martinsen's solution fails. If one takes moral properties to supervene on non-moral properties, then either one ends up committing one of the two forms of the naturalistic fallacy or else one is left postulating unbelievable brute metaphysical facts. (shrink)