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.

The theorems of the simplest and strongest sensible quantified modal logic include the Barcan Formula and its converse. Both formulas face strong intuitive objections. This paper develops a theory of possibilia to meet those objections.

This is the second edition of an award-winning 1981 book (Princeton University Press and Basil Blackwell, based on the author’s doctoral dissertation) considered to be a classic in the philosophy of language movement known variously as the New Theory of Reference or the Direct-Reference Theory, as well as in the metaphysics of modal essentialism that is related to this philosophy of language.

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)

In his recently published paper, ‘The Nature of Possibility,’ David Armstrong presents an account of possibility which, he correctly claims, is partly an elaboration of the early Wittgenstein's. Both are combinatorialists. That is to say, both hold that there is a fixed ontology of individuals, properties and relations whose combinations determine the range of all possible states of affairs, and therewith the range of all those totalities of states of affairs which they call possible worlds.But Armstrong's account, I believe, is (...) fatally flawed in ways that Wittgenstein's isn't. And this, I shall argue, is mainly because Armstrong is both an actualist, whose fixed ontology is one of actual individuals, properties and relations, and a reductionist, who tries to reduce the notion of possibility to that of ߢallߣ their combinations. Armstrong seems to think that Wittgenstein at least shares his actualism, and perhaps even his reductionism. (shrink)

The simplest quantified modal logic combines classical quantification theory with the propositional modal logic K. The models of simple QML relativize predication to possible worlds and treat the quantifier as ranging over a single fixed domain of objects. But this simple QML has features that are objectionable to actualists. By contrast, Kripke-models, with their varying domains and restricted quantifiers, seem to eliminate these features. But in fact, Kripke-models also have features to which actualists object. Though these philosophers have introduced variations (...) on Kripke-models to eliminate their objectionable features, the most well-known variations all have difficulties of their own. The present authors reexamine simple QML and discover that, in addition to having a possibilist interpretation, it has an actualist interpretation as well. By introducing a new sort of existing abstract entity, the contingently nonconcrete, they show that the seeming drawbacks of the simplest QML are not drawbacks at all. Thus, simple QML is independent of certain metaphysical questions. (shrink)

This book tackles the issues that arise in connection with intensional logic -- a formal system for representing and explaining the apparent failures of certain important principles of inference such as the substitution of identicals and existential generalization -- and intentional states --mental states such as beliefs, hopes, and desires that are directed towards the world. The theory offers a unified explanation of the various kinds of inferential failures associated with intensional logic but also unifies the study of intensional contexts (...) and intentional states by grounding the explanation of both phenomena in a single theory. When an axiomatized realm of abstract entities is added to the metaphysical structure of the world, we can use them to identify and individuate the contents of directed mental states. The special abstract entities can be viewed as the objectified contents of mental files, and they play a crucial role in the analysis of truth conditions of the sentences involved in inferential failures. (shrink)

In this book Terence Parsons revives the older tradition of taking such objects at face value. Using various modern techniques from logic and the philosophy of language, he formulates a metaphysical theory of nonexistent objects. The theory is given a formalization in symbolism rich enough to contain definite descriptions, modal operators, and epistemic contexts, and the book includes a discussion which relates the formalized theory explicitly to English.

Actualists who believe in possible worlds typically regard them as "abstract" objects of some special sort. For example, Alvin Plantinga takes worlds to be maximal possible states-of-affairs, all of which "exist", as actualism requires, but only one of which "obtains". Views like Plantinga's run into difficulty in the interpretation of statements of "iterated" modality, statements about what is "possible" for individuals that "could" exist but that do not actually exist. These statements seem to require the existence of "singular" states-Of-affairs that (...) have nonactual individuals as constituents, a requirement that is incompatible with actualism. One can try to avoid the troublesome singular states-of-affairs by introducing "unexemplified individual essences" and maintaining that these are the true constituents of the required states-of-affairs, rather than the nonactual possibles themselves. However, serious arguments are raised against this employment of individual essences. (shrink)

A nonexistent possible is a particular concrete object which exists in some possible world but doesn't exist in the actual world. A definite description may be said to individuate a nonexistent possible if just one possible object satisfies the condition specified by that description, and this possible object doesn't exist in the actual world. Given a plausible form of mereological essentialism, certain mereological and causal descriptions which determine a thing's composition individuate nonexistent possible hunks of matter which are mereological or (...) causal products of actual objects. Other sorts of descriptions such as 'the possible fat man in that doorway' and ones associated with typical fictional, imaginary, and mythical things do not individuate a nonexistent possible, and it is problematical whether we can individuate a nonexistent possible which is disjoint, viz., one which is not a mereological or causal product of actual objects. (shrink)

In "Actualism or Possibilism?" (Philosophical Studies, 84 (2-3), December 1996), James Tomberlin develops two challenges for actualism. The challenges are to account for the truth of certain sentences without appealing to merely possible objects. After canvassing the main actualist attempts to account for these phenomena, he then criticizes the new conception of actualism that we described in our paper "In Defense of the Simplest Quantified Modal Logic" (Philosophical Perspectives 8: Philosophy of Logic and Language, Atascadero, CA: Ridgeview, 1994). We respond (...) to Tomberlin's criticism by showing that we wouldn't analyze the problematic claim (e.g., "Ponce de Leon searched for the fountain of youth") in the way he suggests. (shrink)

In H-N. Castañeda's ontology, a fundamental Fregean distinction is drawn between unsaturated and saturated entities, the former corresponding to predicative aspects of reality, the latter to individuals, that is, to items which can be referred to by means of singular terms1. Within saturated entities, Castañeda attempts to distinguish between abstract and concrete individuals. Sets and Platonic Forms of the F-ness-type are the typical examples of the former category2. As to the latter category instead, concrete individual guises represent both the bottom (...) layer in a hypothetical ontological hierarchy of individuals which has Platonic Forms at its top, and the first step in the psychological process of world cognition, which moves from the most concrete object to the most abstract3. Among concrete individual guises, moreover, Castañeda draws a further ontological distinction between possible and impossible guises, according to the different behavior guises display with respect to the possibility of existing4. Both kinds of guises, however, share that feature which enables to qualify them as guises, i.e. that of being bundles of properties. Every guise is indeed constituted out of (a certain set of) properties, or better predicative aspects5. The predication to a guise of one of its constitutive properties is taken by Castañeda as the primary sense of predication. He calls it Meinongian, or internal, predication (in symbols: "a(F)", where "a" stands for a guise and "F" for one of its constitutive properties)6. For Castañeda, moreover, the main linguistic tool by means of which a guise is denoted is a definite description, insofar as such a description clearly reveals the properties which a guise internally possesses7. Thus, we can say that "the F- er is F" is a typical expression of an internal predication of a property F to the guise denoted by the definite description "the F". If we take "F" as a metavariable for properties, we can say that the above formulation corresponds to what Routley has called the Characterization Postulate8. Now what we want to scrutinize in this paper is, first, whether the following four theses of Castañeda's Guise Theory are really compatible.. (shrink)

A theory of intentionality is outlined, in which the desideratum that the intentional be the same as the real object is argued for in terms of an anti-realist ontology. According to such an ontology, an ordinary object is in itself an object of discourse taken as intentional when posited phenomenologically and as possible when posited naturalistically, i.e. as not existing in some possible worlds but as existing in others. If the actual world is included among the latter, the object deserves (...) to be called "rear". Qua possible object, it answers to a principle of individuation which also works as a criterion of discrimination. According to such a principle, any possible object has a counterfactual individualising property which takes substance plus origin in a given spacetime as the object's essential properties, where it exists. It is, moreover, an object of discourse insofar as it generically depends, for its own being, on a singular term being publicly used to refer to it. (shrink)

In ‘Naming and Necessity,’ Saul Kripke defends a number of essentialist claims. One of them is that having a certain origin is a necessary property of a material thing. Used in connection with a human being or, presumably, a living thing of another kind whose members sexually reproduce, ‘necessity of origin’ means that the organism must have been born of those individuals who are its parents, i.e., whose body tissues are sources of the sperm and egg from which it issued, (...) in the actual world. To say that the origin of an inanimate material thing is necessary is to say that having its origin in the hunk of matter from which it came is essential to it. (shrink)

Peter J. King; Lycan on Lewis and Meinong1, Proceedings of the Aristotelian Society, Volume 93, Issue 1, 1 June 1993, Pages 193–202, https://doi.org/10.1093/ari.