I investigate two asymmetrical approaches to knowledge of absolute possibility and of necessity--one which treats knowledge of possibility as more fundamental, the other according epistemological priority to necessity. Two necessary conditions for the success of an asymmetrical approach are proposed. I argue that a possibility-based approach seems unable to meet my second condition, but that on certain assumptions--including, pivotally, the assumption that logical and conceptual necessities, while absolute, do not exhaust the class of absolute necessities--a necessity-based approach may be able (...) to do so. (shrink)

This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

This paper offers a detailed criticism of different versions of modal scepticism proposed by Van Inwagen and Hawke, and, against these views, attempts to vindicate our reliance on thought experiments in philosophy. More than one different meaning of “ modal scepticism” will be distinguished. Focusing mainly on Hawke’s more detailed view I argue that none of these versions of modal scepticism is compelling, since sceptical conclusions depend on an untenable and, perhaps, incoherent modal epistemology. With a detailed account of modal (...) defeaters at hand I argue that Van Inwagen and Hawke’s scepticism is either groundless, or it leads to boundless and unacceptable modal scepticism. Additionally, I show that Hawke’s conception of analogical modal reasoning is problematic. Either his principle of similarity is arbitrary or it begs the question about modal scepticism. In contrast to Hawke’s restricted view of analogical modal reasoning, I present two examples of analogy-based modal justification of philosophically relevant possibility claims. My criticism of modal scepticism also shows that there is no good reason to insist on a sharp distinction between an unproblematic and a presumably dubious kind of modality. The upshot is that in absence of proper defeaters both Yablo-style conceivability and properly applied analogical reasoning are reliable guides to possibility, and also that modal justification comes in degrees. The proposed framework of defeaters of modal justification as well as the analysed examples of analogical modal reasoning trace out interesting new areas for further discussions. (shrink)

In this paper, we argue that ‘Weak Modal Rationalism’, which is the view that ideal primary positive conceivability entails primary metaphysical possibility, is self-defeating. To this end, we outline two reductio arguments against ‘Weak Modal Rationalism’. The first reductio shows that, from supposing that ‘Weak Modal Rationalism’ is true, it follows that conceivability both is and is not conclusive evidence for possibility. The second reductio shows that, from supposing that ‘Weak Modal Rationalism’ is true, it follows that it is possible (...) that ‘Weak Modal Rationalism’ is necessarily false, and hence that ‘Weak Modal Rationalism’ is false. We then argue that adopting a weaker position according to which conceivability is merely prima facie evidence for possibility provides limited protection from our criticism of conceivability arguments. (shrink)

It is argued that there are three main forms of necessity --the metaphysical, the natural and the normative--and that none of them is reducible to the others or to any other form of necessity. In arguing for a distinctive form of natural necessity, it is necessary to refute a version of the doctrine of scientific essentialism; and in arguing for a distinctive form of normative necessity, it is necessary to refute certain traditional and contemporary versions of ethical naturalism.

In this paper I argue that a priori arguments fail to present any real problem for physicalism. They beg the question against physicalism in the sense that the argument will only seem compelling if one is already assuming that qualitative properties are nonphysical. To show this I will present the reverse-zombie and reverse-knowledge arguments. The only evidence against physicalism is a priori arguments, but there are also a priori arguments against dualism of exactly the same variety. Each of these parity (...) arguments has premises that are just as intuitively plausible, and it cannot be the case that both the traditional scenarios and the reverse-scenarios are all ideally conceivable. Given this one set must be merely prima facie conceivable and only empirical methods will tell us which is which. So, by the time a priori methodology will be of any use it will be too late. (shrink)

Many important metaphysical arguments validly deduce an actuality from a possibility. For example: Because it is possible for me to exist in the absence of anything material, I am not my body. I argue that there is no reason to suppose that our capacity for modal judgment is equal to the task of determining whether the "possibility" premise of any of these arguments is true. I connect this thesis with Stephen Yablo's recent work on the epistemology of modal statements.

During the last two decades, several different anti-physicalist arguments based on an epistemic or conceptual gap between the phenomenal and the physical have been proposed. The most promising physicalist line of defense in the face of these arguments – the Phenomenal Concept Strategy – is based on the idea that these epistemic and conceptual gaps can be explained by appeal to the nature of phenomenal concepts rather than the nature of non-physical phenomenal properties. Phenomenal concepts, on this proposal, involve unique (...) cognitive mechanisms, but none that could not be fully physically implemented. David Chalmers has recently presented a Master Argument to show that the Phenomenal Concept Strategy – not just this or that version of it, but any version of it – fails. Chalmers argues that the phenomenal concepts posited by such theories are either not physicalistically explicable, or they cannot explain our epistemic situation with regard to qualia. I argue that it is his Master Argument that fails. My claim is his argument does not provide any new reasons to reject the Phenomenal Concept Strategy. I also argue that, although the Phenomenal Concept Strategy is successful in showing that the physicalist is not rationally compelled to give up physicalism in the light of the anti-physicalist arguments, the anti-physicalist is not rationally compelled to give up the anti-physicalist argument in the light of the Phenomenal Concept Strategy either. (shrink)

This book, one of the first full-length studies of the modalities to emerge from the debate to which Saul Kripke, David Lewis, Ruth Marcus, and others are contributing, is an exploration and defense of the notion of modality de re, the idea that objects have both essential and accidental properties. Plantinga develops his argument by means of the notion of possible worlds and ranges over such key problems as the nature of essence, transworld identity, negative existential propositions, and the existence (...) of unactual objects in other possible worlds. He also applies his logical theories to the elucidation of two problems in the philosophy of religion: the problem of evil and the ontological argument. (shrink)

It is my aim in this paper to show that the contemporary assimilation of essence to modality is fundamentally misguided and that, as a consequence, the corresponding conception of metaphysics should be given up. It is not my view that the modal account fails to capture anything which might reasonably be called a concept of essence. My point, rather, is that the notion of essence which is of central importance to the metaphysics of identity is not to be understood in (...) modal terms or even to be regarded as extensionally equivalent to a modal notion. The one notion is, if I am right, a highly refined version of the other; it is like a sieve which performs a similar function but with a much finer mesh. (shrink)

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. One purpose of this paper is to argue that the notion is not fruitfully explicated in terms of the imagination. The most natural way of presenting a notion of conceivability qua imaginability is open to cogent criticism. In order to avoid such criticism, an advocate of the modal insightfulness of the imagination (...) must broaden the idea of what it is to be imaginable. I argue that this required broadening renders the imagination idle . Consequently, I distinguish two different accounts of the evidential basis of modal knowledge and present a more general argument that concludes that the very notion of conceivability should be eschewed in modal epistemology. (shrink)

In recent years the 'zombie argument' has come to occupy a central role in the case against physicalist views of consciousness, in large part because of the powerful advocacy it has received from David Chalmers.1 In this paper I seek to neutralize it by showing that a parallel argument can be run for physicalism, an argument turning on the conceivability of what I shall call anti-zombies. I shall argue that the result is a stand-off, and that the zombie argument offers (...) no independent reason to reject physicalism. (shrink)

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. In recent discussions, some have attempted to explicate the notion in terms of epistemic possibility. There are, however, two notions of epistemic possibility, a more familiar one and a novel one. I argue that these two notions are independent of one another. Both are irrelevant to an account of modal knowledge on (...) the predominant view of modal reality. Only the novel notion is relevant and apt on the competing view of modal reality; but this latter view is problematic in light of compelling counterexamples. Insufficient care regarding the independent notions of epistemic possibility can lead to two problems: a gross problem of conflation and a more subtle problem of obscuring a crucial fact of modal epistemology. Either problem needlessly hampers efforts to develop an adequate account of modal knowledge. I conclude that the familiar notion of epistemic possibility should be eschewed in the context of modal epistemology. (shrink)

Two-dimensional approaches to semantics, broadly understood, recognize two "dimensions" of the meaning or content of linguistic items. On these approaches, expressions and their utterances are associated with two different sorts of semantic values, which play different explanatory roles. Typically, one semantic value is associated with reference and ordinary truth-conditions, while the other is associated with the way that reference and truth-conditions depend on the external world. The second sort of semantic value is often held to play a distinctive role in (...) analyzing matters of cognitive significance and/or context-dependence. (shrink)

This is a revised and updated version of Swinburne's controversial treatment of the eternal philosophical problem of the relation between mind and body. He argues that we can only make sense of the interaction between the mental and the physical in terms of the soul, and that there is no scientific explanation of the evolution of the soul.

This paper was chosen by The Philosopher’s Annual as one of the ten best articles appearing in print in 2000. Reprinted in Volume XXIII of The Philosopher’s Annual. In his very influential book David Chalmers argues that if physicalism is true then every positive truth is a priori entailed by the full physical description – this is called “the a priori entailment thesis – but ascriptions of phenomenal consciousness are not so entailed and he concludes that Physicalism is false. As (...) he puts it, “zombies” are metaphysically possible. I attempt to show that this argument is refuted by considering an analogous argument in the mouth of a zombie. The conclusion of this argument is false so one of the premises is false. I argue at length that this shows that the original conceivability argument also has a false premise and so is invalid. (shrink)

There is a long tradition in philosophy of using a priori methods to draw conclusions about what is possible and what is necessary, and often in turn to draw conclusions about matters of substantive metaphysics. Arguments like this typically have three steps: first an epistemic claim , from there to a modal claim , and from there to a metaphysical claim.

Is conceptual analysis required for reductive explanation? If there is no a priori entailment from microphysical truths to phenomenal truths, does reductive explanation of the phenomenal fail? We say yes . Ned Block and Robert Stalnaker say no.

Frank Jackson champions the cause of conceptual analysis as central to philosophical inquiry. In recent years conceptual analysis has been undervalued and widely misunderstood, suggests Jackson. He argues that such analysis is mistakenly clouded in mystery, preventing a whole range of important questions from being productively addressed. He anchors his argument in discussions of specific philosophical issues, starting with the metaphysical doctrine of physicalism and moving on, via free will, meaning, personal identity, motion, and change, to ethics and the philosophy (...) of color. In this way the book not only offers a methodological program for philosophy, but also casts new light on some much-debated problems and their interrelations. (shrink)

The book is an extended study of the problem of consciousness. After setting up the problem, I argue that reductive explanation of consciousness is impossible , and that if one takes consciousness seriously, one has to go beyond a strict materialist framework. In the second half of the book, I move toward a positive theory of consciousness with fundamental laws linking the physical and the experiential in a systematic way. Finally, I use the ideas and arguments developed earlier to defend (...) a form of strong artificial intelligence and to analyze some problems in the foundations of quantum mechanics. (shrink)

Modal rationalism includes the thesis that ideal primary positive conceivability entails primary possibility. Modal monism is the thesis that the space of logically possible worlds is coextensive with the space of metaphysically possible worlds. In this paper I explore the relation between the two theses. My aim is to show that the former thesis implies the latter thesis, and that problems with the latter make the former implausible as a complete picture of the epistemology of modality. My argument explores the (...) relation between logical modality and metaphysical modality. (shrink)

A number of popular arguments for dualism start from a premise about an epistemic gap between physical truths about truths about consciousness, and infer an ontological gap between physical processes and consciousness. Arguments of this sort include the conceivability argument, the knowledge argument, the explanatory-gap argument, and the property dualism argument. Such arguments are often resisted on the grounds that epistemic premises do not entail ontological conclusion. My view is that one can legitimately infer ontological conclusions from epistemic premises, if (...) one is very careful about how one reasons. To do so, the best way is to reason first from epistemic premises to modal conclusions , and from there to ontological conclusions. Here, the crucial issue is the link between the epistemic and modal domains. How can one reason from theses about what is knowable or conceivable to theses about what is necessary or possible? To bridge the epistemic and modal domains, the framework of two-dimensional semantics can play a central role. I have used this framework in earlier work to mount an argument against materialism. Here, I want to revisit the argument, laying it out in a more explicit and careful form, and responding to a number of objections. In what follows I will concentrate mostly on the conceivability argument. I think that very similar considerations apply to the other arguments mentioned above, however. In the final section of the paper, I show how this analysis might yield a unified treatment of a number of anti-materialist arguments. (shrink)

How do we know what's (metaphysically) possible and impossible? Arguments from Kripke and Putnam suggest that possibility is not merely a matter of (coherent) conceivability/imaginability. For example, we can coherently imagine that Hesperus and Phosphorus are distinct objects even though they are not possibly distinct. Despite this apparent problem, we suggest, nevertheless, that imagination plays an important role in an adequate modal epistemology. When we discover what is possible or what is impossible, we generally exploit important connections between what is (...) possible and what we can coherently imagine. We can often come to knowledge of metaphysical modality a priori. (shrink)

In the history of modern philosophy systematic connections were assumed to hold between the modal concepts of logical possibility and necessity and the concept of conceivability. However, in the eyes of many contemporary philosophers, insuperable objections face any attempt to analyze the modal concepts in terms of conceivability. It is important to keep in mind that a philosophical explanation of modality does not have to take the form of a reductive analysis. In this paper I attempt to provide a response-dependent (...) account of the modal concepts in terms of conceivability along the lines of a nonreductive model of explanation. (shrink)

I think recent discussions of content and reference have not paid enough attention to the role of language as a convention-governed system of communication. With this as a background theme, I explain the role of A-intensions in elucidating one important notion of content and correlative notions of reference.

_Matters of Mind_ examines the mind-body problem. It offers a chapter by chapter analysis of debates surrounding the problem, including visual experience, consciousness and the problem of Zombies and Ghosts. It will prove invaluable for those interested in epistemology, philosophy of mind and cognitive science.

The following abbreviations are used to reference Berkeley’s works: PC “Philosophical Commentaries‘ Works 1:9--104 NTV An Essay Towards a New Theory of Vision Works 1:171--239 PHK Of the Principles of Human Knowledge: Part 1 Works 2:41--113 3D Three Dialogues between Hylas and Philonous Works 2:163--263 DM De Motu, or The Principle and Nature of Motion and the Cause of the Communication of Motions, trans. A.A. Luce Works 4:31--52.