It follows from Humean principles of plenitude, I argue, that island universes are possible: physical reality might have 'absolutely isolated' parts. This makes trouble for Lewis's modal realism; but the realist has a way out. First, accept absolute actuality, which is defensible, I argue, on independent grounds. Second, revise the standard analysis of modality: modal operators are 'plural', not 'individual', quantifiers over possible worlds. This solves the problem of island universes and confers three additional benefits: an 'unqualified' principle of compossibility (...) can be accepted; the possibility of nothing can be accommodated; and the identity of indiscernible worlds can be decisively refuted. (shrink)

This volume contains eighteen papers, three with new postscripts, that were written over the past 35 years. Five of the papers have not been previously published. Together they provide a comprehensive account of modal reality—the realm of possible worlds—from a Humean perspective, with excursions into neighboring topics in metaphysics. Part 1 sketches an account of reality as a whole, both the mathematical and the modal, defending a form of plenitudinous realism: every consistent proposition is true of some portion of reality. (...) Part 2 presents and defends a realist theory of concrete possible worlds with an absolute ontological distinction between the actual and the merely possible. Part 3 presents and defends a Humean account of modal plenitude, formulating and endorsing principles of recombination, of plenitude of possible structures, and of plenitude of alien contents. Part 4 applies the Humean account to truthmaking, mereology, spacetime, and quantities. I argue that holding fast to Humean strictures leads to views that differ in radical ways from those put forth by contemporary metaphysicians. (shrink)

In this chapter, I survey what I call Lewisian approaches to modality: approaches that analyze modality in terms of concrete possible worlds and their parts. I take the following four theses to be characteristic of Lewisian approaches to modality. (1) There is no primitive modality. (2) There exists a plurality of concrete possible worlds. (3) Actuality is an indexical concept. (4) Modality de re is to be analyzed in terms of counterparts, not transworld identity. After an introductory section in which (...) I motivate analyzing modality in terms of possible worlds, I devote one section to each of these four theses. For each thesis, I take Lewis’s interpretation and defense as my starting point. I then consider and endorse alternative ways of accepting the thesis, some of which disagree substantially with Lewis’s interpretation or defense. There is more than one way to be a Lewisian about modality. (shrink)

I am a realist of a metaphysical stripe. I believe in an immense realm of "modal" and "abstract" entities, of entities that are neither part of, nor stand in any causal relation to, the actual, concrete world. For starters: I believe in possible worlds and individuals; in propositions, properties, and relations (both abundantly and sparsely conceived); in mathematical objects and structures; and in sets (or classes) of whatever I believe in. Call these sorts of entity, and the reality they comprise, (...) metaphysical. In contrast, call the actual, concrete entities, and the reality they comprise, physical. Physical and metaphysical reality together comprise all that there is. In this paper, it is not my aim to defend realism about any particular metaphysical sort of entity. Rather, I ask quite generally whether and how any brand of realism about metaphysical sorts of entity could be justified? (shrink)

Composition as identity, as I understand it, is a theory of the composite structure of reality. The theory’s underlying logic is irreducibly plural; its fundamental primitive is a generalized identity relation that takes either plural or singular arguments. Strong versions of the theory that incorporate a generalized version of the indiscernibility of identicals are incompatible with the framework of plural logic, and should be rejected. Weak versions of the theory that are based on the idea that composition is merely analogous (...) to identity are too weak to be interesting, lacking in metaphysical consequence. I defend a moderate version according to which composition is a kind of identity, and argue that the difference is metaphysically substantial, not merely terminological. I then consider whether the notion of generalized identity, though fundamental, can be elucidated in modal terms by reverse engineering Hume’s Dictum. Unfortunately, for realists about possible worlds, such as myself,... (shrink)

According to David Lewis, a realist about possible worlds must hold that actuality is relative: the worlds are ontologically all on a par; the actual and the merely possible differ, not absolutely, but in how they relate to us. Call this 'Lewisian realism'. The alternative, 'Leibnizian realism', holds that actuality is an absolute property that marks a distinction in ontological status. Lewis presents two arguments against Leibnizian realism. First, he argues that the Leibnizian realist cannot account for the contingency of (...) actuality. Second, he argues that the Leibnizian realist cannot explain why skepticism about one's own actuality is absurd. In this paper, I mount a defense of Leibnizian realism. (shrink)

The article explicates a notion of prudence according to which an agent acts prudently if he acts so as to satisfy not only his present preferences, but his past and future preferences as well. A simplified decision-theoretic framework is developed within which three analyses of prudence are presented and compared. That analysis is defended which can best handle cases in which an agent's present act will affect his future preferences.

If realism about possible worlds is to succeed in eliminating primitive modality, it must provide an 'analysis' of possible world: nonmodal criteria for demarcating one world from another. This David Lewis has done. Lewis holds, roughly, that worlds are maximal unified regions of logical space. So far, so good. But what Lewis means by 'unification' is too narrow, I think, in two different ways. First, for Lewis, all worlds are (almost) 'globally' unified: at any world, (almost) every part is directly (...) linked to (almost) every other part. I hold instead that some worlds are 'locally' unified: at some worlds, parts are directly linked only to "neighboring" parts. Second, for Lewis, each world is (analogically) 'spatio-temporally' unified; every world is 'spatio-temporally' isolated from every other. I hold instead: a world may be unified by nonspatio-temporal relations; every world is 'absolutely' isolated from every other. If I am right, Lewis's conception of logical space is impoverished: perfectly respectable worlds are missing. (shrink)

Humeans have a problem with quantities. A core principle of any Humean account of modality is that fundamental entities can freely recombine. But determinate quantities, if fundamental, seem to violate this core principle: determinate quantities belonging to the same determinable necessarily exclude one another. Call this the problem of exclusion. Prominent Humeans have responded in various ways. Wittgenstein, when he resurfaced to philosophy, gave the problem of exclusion as a reason to abandon the logical atomism of the Tractatus with its (...) free recombination of elementary propositions. Armstrong promoted a mereological solution to the problem of exclusion; but his account fails in manifold ways to provide a general solution to the problem. Lewis studiously avoided committing to any one solution, trusting simply that, since Humeanism was true, there had to be some solution. Abandonment; failure; avoidance: we Humeans need to do better. -/- In this paper, I present what I take to be the best account of quantities, tailoring it where needed to meet Humean demands as well as my own prior commitment to quidditism, and my own comparativist inclinations. In short: determinables, not determinates, are the fundamental properties, and freely recombine; determinates arise from the instantiation of determinables in an enhanced world structure; determinate quantities may be local (in a sense to be explained), but they are not intrinsic. Is the account I end up with Humean? Not, unfortunately, as it stands: the problem of exclusion still rears its ugly head. After dismissing a failed attempt at a solution, I consider in the final section the two viable Humean options. One attributes the source of the necessary exclusions to conventional definition, the other attributes it to logic. The first is safe and familiar, but not a response I can accept given my other commitments. The second is more radical and less familiar; but I am convinced it is on the right track. I don’t have space to develop it much here, but I put it out for future research. (shrink)

Some argue, following Bertrand Russell, that because general truths are not entailed by particular truths, general facts must be posited to exist in addition to particular facts. I argue on the contrary that because general truths (globally) supervene on particular truths, general facts are not needed in addition to particular facts; indeed, if one accepts the Humean denial of necessary connections between distinct existents, one can further conclude that there are no general facts. When entailment and supervenience do not coincide (...) it is only failure of supervenience, not failure of entailment, that carries ontological import. (shrink)

Which mathematical structures are possible, that is, instantiated by the concrete inhabitants of some possible world? Are there worlds with four-dimensional space? With infinite-dimensional space? Whence comes our knowledge of the possibility of structures? In this paper, I develop and defend a principle of plenitude according to which any mathematically natural generalization of possible structure is itself possible. I motivate the principle pragmatically by way of the role that logical possibility plays in our inquiry into the world.

These original essays explore the philosophical implications of Newton's work.

According to the Truthmaker Principle: every truth has a truthmaker. Attempts to come to grips with the Truthmaker Principle played a prominent role in Lewis’s metaphysical writings over the last fifteen years of his career. Although Lewis agreed that the truth of propositions must somehow be ontologically grounded, the Truthmaker Principle was too strong: it conflicted with two of Lewis’s most fundamental metaphysical assumptions, the uniqueness of composition and the Humean denial of necessary connections. Lewis endorsed instead a weaker principle: (...) Truth Supervenes on Being. But towards the end of his career, he changed course, noting that his critique of the Truthmaker Principle rested on essentialist assumptions that he, as a counterpart theorist, does not accept. Once freed from those assumptions, a counterpart theorist can accept the Truthmaker Principle after all without buying into unmereological composition and mysterious necessary connections. (shrink)

In this chapter, I evaluate various conceptions of distance. Of the two most prominent, one takes distance relations to be intrinsic, the other extrinsic. I recommend pluralism: different conceptions can peacefully coexist as long as each holds sway over a distinct region of logical space. But when one asks which conception holds sway at the actual world, one conception stands out. It is the conception of distance embodied in differential geometry, what I call the Gaussian conception. On this conception, all (...) fundamental facts about distance are “local” facts.” But there is a problem: the Gaussian conception, notwithstanding its mathematical and physical credentials, appears metaphysically suspicious on Humean grounds. In the final section, I suggest that the Gaussian conception can be given a sound metaphysical footing in terms of non-standard analysis. (shrink)

The most commonly heard proposals for reducing possible worlds to language succumb to a simple cardinality argument: it can be shown that there are more possible worlds than there are linguistic entities provided by the proposal. In this paper, I show how the standard proposals can be generalized in a natural way so as to make better use of the resources available to them, and thereby circumvent the cardinality argument. Once it is seen just what the limitations are on these (...) more general proposals, it can be clearly seen where the real difficulty lies with any attempt to reduce possible worlds to language. Roughly, the difficulty is this: no actual language could have the descriptive resources needed to represent all the ways things might have been. I conclude by arguing that this same difficulty spells doom for any nominalist or conceptualist proposal for reducing possible worlds. (shrink)

Moderate composition as identity holds that there is a generalized identity relation, “being the same portion of reality,” of which composition and numerical identity are distinct species. Composition is a genuine kind of identity; but unlike numerical identity, it fails to satisfy Leibniz’s Law. A composite whole and its parts differ with respect to their numerical properties: the whole is one; the parts (collectively) are many. Moderate composition as identity faces the challenge: how, in the absence of Leibniz’s Law, can (...) one characterize what counts as a genuine kind of identity? This paper explores a promising answer: a genuine kind of identity must satisfy a version of Leibniz’s Law restricted to properties that ascribe qualitative character. Strong composition as identity holds that there is only one identity relation, that it satisfies Leibniz’s Law, and that the parts are identical with the whole that they compose. Strong composition as identity faces the challenge of showing that numerical properties do not provide counterexamples to Leibniz’s Law, and doing so in a way that is compatible with the framework of plural logic that is needed to formulate the theory. The most promising way to do this is to hold that plural logic is fundamental at the level of our representations, but not fundamental at the level of being. At the level of being, portions of reality cannot be characterized as either singular or plural. It turns out that the proposed moderate theory and the proposed strong theory are one and the same. In spite of its many attractions, I reject it. The main issue has to do with whether slice-sensitive emergent properties are possible. I argue that they are, making use both of specific examples and general principles of modal plenitude. I do not claim that my arguments are irresistible. But they cannot be evaded as easily as a related argument against strong composition as identity given by Kris McDaniel. I critically examine McDaniel’s argument to pave the way for my own. (shrink)

The Forrest-Armstrong argument, as reconfigured by David Lewis, is a reductio against an unrestricted principle of recombination. There is a gap in the argument which Lewis thought could be bridged by an appeal to recombination. After presenting the argument, I show that no plausible principle of recombination can bridge the gap. But other plausible principles of plenitude can bridge the gap, both principles of plenitude for world contents and principles of plenitude for world structures. I conclude that the Forrest-Armstrong argument, (...) when fortified in one of these ways, demands that unrestricted recombination be rejected. The appropriate restriction comes from a consideration of what world structures are possible. I argue that, although there are too many worlds to form a set, for any world, the individuals at that world do form a set. To defend it I invoke a principle of Limitation of Size together with an iterative conception of structure. (shrink)

An attempt to clarify how the problem of absolute time and the problem of absolute motion relate to one another, especially with respect to causal attributions involving time and motion.

Modal sentences of the form "every F might be G" and "some F must be G" have a threefold ambiguity. in addition to the familiar readings "de dicto" and "de re", there is a third reading on which they are examples of the "plural de re": they attribute a modal property to the F's plurally in a way that cannot in general be reduced to an attribution of modal properties to the individual F's. The plural "de re" readings of modal (...) sentences cannot be captured within standard quantified modal logic. I consider various strategies for extending standard quantified modal logic so as to provide analyses of the readings in question. I argue that the ambiguity in question is associated with the scope of the general term 'F'; and that plural quantifiers can be introduced for purposes of representing the scope of a general term. Moreover, plural quantifiers provide the only fully adequate solution that keeps within the framework of quantified modal logic. (shrink)

In this introductory chapter to my collection of papers, Modal Matters, I present my tripartite account of reality. First, I endorse a plenitudinous Platonism: for every consistent mathematical theory, there is in reality a mathematical system in which the theory is true. Second, for any way of distributing fundamental qualitative properties over mathematical structures, there is a portion of reality that has that structure with fundamental properties distributed in that way; some of these portions of reality, when isolated, are the (...) possible worlds. Third, there is a fundamental ontological distinction between those portions of reality that are absolutely actual, and those that are merely possible. In the course of developing this account of reality, I sketch my views on logic, mathematics, modality, qualitative character, and actuality. An austere Humeanism that rejects all primitive modality motivates and constrains my views. (shrink)

David Lewis's book 'On the Plurality of Worlds' mounts an extended defense of the thesis of modal realism, that the world we inhabit the entire cosmos of which we are a part is but one of a vast plurality of worlds, or cosmoi, all causally and spatiotemporally isolated from one another. The purpose of this article is to provide an accessible summary of the main positions and arguments in Lewis's book.

In sections 1 through 5, I develop in detail what I call the standard theory of worlds and propositions, and I discuss a number of purported objections. The theory consists of five theses. The first two theses, presented in section 1, assert that the propositions form a Boolean algebra with respect to implication, and that the algebra is complete, respectively. In section 2, I introduce the notion of logical space: it is a field of sets that represents the propositional structure (...) and whose space consists of all and only the worlds. The next three theses, presented in sections 3, 4, and 5, respectively, guarantee the existence of logical space, and further constrain its structure. The third thesis asserts that the set of propositions true at any world is maximal consistent; the fourth thesis that any two worlds are separated by a proposition; the fifth thesis that only one proposition is false at every world. In sections 6 through 10, I turn to the problem of reduction. In sections 6 and 7, I show how the standard theory can be used to support either a reduction of worlds to propositions or a reduction of propositions to worlds. A number of proposition-based theories are developed in section 6, and compared with Adams's world-story theory. A world-based theory is developed in section?, and Stalnaker's account of the matter is discussed. Before passing judgment on the proposition based and world-based theories, I ask in sections 8 and 9 whether both worlds and propositions might be reduced to something else. In section 8, I consider reductions to linguistic entities; in section 9, reductions to unfounded sets. After rejecting the possibility of eliminating both worlds and propositions, I return in section 10 to the possibility of eliminating one in favor of the other. I conclude, somewhat tentatively, that neither worlds nor propositions should be reduced one to the other, that both worlds and propositions should be taken as basic to our ontology. (shrink)

Walter Sinnott-Armstrong, Diana Raffman, Nicholas Asher, Modality, Morality, and Belief, Essays in Honor of Ruth Barcan Marcus.Terence Parsons, Ruth Barcan Marcus and the Barcan Formula.Robert Stalnaker, The Interaction of Modality with Quantification and Identity.Maxwell J. Cresswell, S1 is not so Simple.David Kaplan, A Problem in Possible-world Semantics.Charles Parsons, Structuralism and the Concept of Set.

Part 2 is concerned, in chapter 4, with semantic features of dates and duration terms, and, in chapter 5, with the conventionality of measurements of duration, and the incoherence of durationless instants.

The knowledge-centric Theory of Mind research program suggested by Phillips et al. stands to gain significant value by embracing a neurocognitive approach that takes full advantage of techniques like fMRI and EEG. This neurocognitive approach has already begun providing important insights into the mechanisms of knowledge attribution, insights which support the claim that it is more basic than belief attribution.

The thesis that knowledge is a factive mental state plays a central role in knowledge-first epistemology, but accepting this thesis requires also accepting an unusually severe version of externalism about the mind. On this strong attitude externalism, whether S is in the mental state of knowledge can and often will rapidly change in virtue of changes in external states of reality with which S has no causal contact. It is commonly thought that this externalism requirement originates in the factivity of (...) knowledge. However, despite a number of recent defenses of non-factive accounts of knowledge, epistemology has yet to consider whether a non-factive approach might produce a version of the mental state thesis that can avoid strong externalism. Here I do just that, exploring how three different proposals for weakening factivity might be adapted to theories of knowledge as a non-factive mental state. Contrary to what we might expect, however, none of these proposals are compatible with anything close to attitude internalism about knowledge—or even a substantially weaker externalism. All told, the widespread view that wraps up the severe externalism required for knowledge to be a mental state in factivity is mistaken. Knowledge’s external-world connection runs far deeper than the factivity constraint. (shrink)

Abstract:This paper is a preliminary attempt to better understand the concept of legitimacy in stakeholder theory. The normative component of stakeholder theory plays a central role in the concept of legitimacy. Though the elaboration of legitimacy contained herein applies generally to all “normative cores” this paper relies on Phillips’s principle of stakeholder fairness and therefore begins with a brief description of this work. This is followed by a discussion of the importance of legitimacy to stakeholder theory as well as the (...) general ambiguity of the term. A distinction is then drawn between normative and derivative legitimacy. Reference to this distinction helps distinguish between a relationship with the organization based on direct moral obligation and one based on the power to help or harm the organization. It is concluded that stakeholders who retain the ability to affect the organization arelegitimate(derivatively), but that this legitimacy is derived from the moral obligation owed other (normative) stakeholders and that the two sorts of legitimacy are importantly different from one another. An example of the normative/derivative distinction at work in managerial decision making is elaborated upon and managerial and research implications are then suggested. (shrink)

This paper outlines the case for a future research program that uses the tools of experimental cognitive science to investigate questions that traditionally fall under the remit of the philosophy of historiography. The central idea is this – the epistemic profile of historians’ representations of the past is largely an empirical matter, determined in no small part by the cognitive processes that produce these representations. However, as the philosophy of historiography is not presently equipped to investigate such cognitive questions, legitimate (...) concerns about evidential quality go largely overlooked. The case of mental state representation provides an excellent illustration of this. Representations of past mental states – the thoughts and fears and knowledge and desires of past agents – play much the same evidential role in historiography as in everyday life, serving in the causal explanation of agents’ behaviors and supporting normative evaluation of those behaviors. However, we have good reason to suspect that the theory of mind processes that support these representations may be more susceptible to error when deployed in the context of historiography than under everyday conditions. This raises worries about the quality of evidence that theory of mind can provide historiography, worries which require experimental cognitive science to properly address. (shrink)

Despite the ubiquity of knowledge attribution in human social cognition, its associated neural and cognitive mechanisms are poorly documented. A wealth of converging evidence in cognitive neuroscience has identified independent perspective-taking and inhibitory processes for belief attribution, but the extent to which these processes are shared by knowledge attribution isn't presently understood. Here, we present the findings of an EEG study designed to directly address this shortcoming. These findings suggest that belief attribution is not a component process in knowledge attribution, (...) contra a standard attitude taken by philosophers. Instead, observed differences in P3b amplitude indicate that knowledge attribution doesn't recruit the strong self-perspective inhibition characteristic of belief attribution. However, both belief and knowledge attribution were observed to display a late slow wave widely associated with mental state attribution, indicating that knowledge attribution also shares in more general processing of others' mental states. These results provide a new perspective both on how we think about knowledge attribution, as well as Theory of Mind processes generally. (shrink)

Leading philosopher of religion D. Z. Phillips argues that intellectuals need not see their task as being for or against religion, but as one of understanding it. What stands in the way of this task are certain methodological assumptions about what enquiry into religion must be. Beginning with Bernard Williams on Greek gods, Phillips goes on to examine these assumptions in the work of Hume, Feuerbach, Marx, Frazer, Tylor, Marett, Freud, Durkheim, Le;vy-Bruhl, Berger and Winch. The result exposes confusion, but (...) also gives logical space to religious belief without advocating personal acceptance of that belief, and shows how the academic study of religion may return to the contemplative task of doing conceptual justice to the world. Religion and the Hermeneutics of Contemplation extends in important ways D. Z. Phillips' seminal 1976 book Religion Without Explanation. It will be of interest to scholars and students of philosophy, anthropology, sociology and theology. (shrink)

It is widely held in philosophy that knowing is not a state of mind. On this view, rather than knowledge itself constituting a mental state, when we know, we occupy a belief state that exhibits some additional non-mental characteristics. Fascinatingly, however, new empirical findings from cognitive neuroscience and experimental philosophy now offer direct, converging evidence that the brain can—and often does—treat knowledge as if it is a mental state in its own right. While some might be tempted to keep the (...) metaphysics of epistemic states separate from the neurocognitive mechanics of our judgements about them, here I will argue that these empirical findings give us sufficient reason to conclude that knowledge is at least sometimes a mental state. The basis of this argument is the epistemological principle of neurocognitive parity—roughly, if the contents of a given judgement reflect the structure of knowledge, so do the neurocognitive mechanics that produced them. This principle, which I defend here, straightforwardly supports the inference from the empirical observation that the brain sometimes treats knowledge like a mental state to the epistemological conclusion that knowledge is at least sometimes a mental state. All told, the composite, belief-centric metaphysics of knowledge widely assumed in epistemology is almost certainly mistaken. (shrink)

Quite likely the most sacrosanct principle in epistemology, it is near-universally accepted that knowledge is factive: knowing that p entails p. Recently, however, Bricker, Buckwalter, and Turri have all argued that we can and often do know approximations that are strictly speaking false. My goal with this paper is to advance this nascent non-factive project in two key ways. First, I provide a critical review of these recent arguments against the factivity of knowledge, allowing us to observe that elements (...) of these arguments mutually reinforce respective weaknesses, thereby offering the non-factive project a much stronger foundation than when these arguments were isolated. Next, I argue tentatively in favor of Bricker’s truthlikeness framework over the representational adequacy account favored by Buckwalter and Turri. Taken together, while none of this constitutes a knock-down argument against factivity, it does allow us to quiet some of the more immediate worries surrounding the non-factive project. (shrink)

Our lives are dominated by technology. We live with and through the achievements of technology. What is true of the rest of life is of course true of medicine. Many of us owe our existence and our continued vigour to some achievement of medical technology. And what is true in a major way of general medicine is to a significant degree true of psychiatry. Prozac has long since arrived, and in its wake an ever-growing armamentarium of new psychotropics; beyond that, (...) neuroscience promises ever more technological advances for the field. -/- However, the effect of technology on the field of psychiatry remains highly ambiguous. On the one hand there are the achievements, both in the science and practice of psychiatry; on the other hand technology's influence on the field threatens its identity as a humanistic practice. In this ambiguity psychiatry is not unique - major thinkers have for a long time been highly ambivalent and concerned about the technological order that now defines modern society. For the future, the danger is that the psychiatrically real becomes that which can be seen, the symptom, and especially that which can be measured. Disorders and treatments might become reduced to what can be defined by diagnostic criteria and what can be mapped out on a scale. -/- This book exams how technology has come to influence and drive psychiatry forward, and considers at just what cost these developments have been made. It includes a range of stimulating and thought-provoking chapters from a range of psychiatrists and philosophers. (shrink)

Here I explore a new line of evidence for belief–credence dualism, the thesis that beliefs and credences are distinct and equally fundamental types of mental states. Despite considerable recent disagreement over this thesis, little attention has been paid in philosophy to differences in how our mindreading systems represent the beliefs and credences of others. Fascinatingly, the systems we rely on to accurately and efficiently track others’ mental states appear to function like belief–credence dualists: Credence is tracked like an emotional state, (...) composed of both representational and affective content, whereas belief is tracked like a bare representational state with no affective component. I argue on a preliminary basis that, in this particular case, the mechanics of mentalizing likely pick out a genuine affective dimension to credence that is absent for belief, further strengthening the converging case for belief–credence dualism. (shrink)