Louis deRosset

Necessitists hold that, necessarily, everything is such that, necessarily, something is identical to it. Timothy Williamson has posed a number of challenges to contingentism, the negation of necessitism. One such challenge is an argument that necessitists can more wholeheartedly embrace possible worlds semantics than can contingentists. If this charge is correct, then necessitists, but not contingentists, can unproblematically exploit the technical successes of possible worlds semantics. I will argue, however, that the charge is incorrect: contingentists can embrace possible worlds semantics as wholeheartedly as necessitists. Williamson offers a criterion for a class of models of quantified modal logic to be intended, and argues on its basis that contingentists must deny that there is an intended class of models. I argue that Williamson’s criterion is objectionable, supply an alternative that does not support Williamson’s argument, and adapt Williamson’s construction of an intended model structure to the needs of contingentist metaphysics.

/Analyticity theorists/, as I will call them, endorse the /doctrine of analyticity in ontology/: if some truth P analytically entails the existence of certain things, then a theory that contains P but does not claim that those things exist is no more ontologically parsimonious than a theory that also claims that they exist. Suppose, for instance, that the existence of a table in a certain location is analytically entailed by the existence and features of certain particles in that location. The doctrine implies that the table's existence requires nothing more of the world than that those particles exist and bear the features in question. Analyticity theorists have alleged that this idea may be used to defend controversial existence claims against a battery of objections. I argue that this style of defense fails, because the doctrine faces counter-examples. An existence claim may be analytically entailed by some truth and still report a substantial further fact.

It is difficult to wander far in contemporary metaphysics without bumping into talk of possible worlds. And reference to possible worlds is not confined to metaphysics. It can be found in contemporary epistemology and ethics, and has even made its way into linguistics and decision theory. What are those possible worlds, the entities to which theorists in these disciplines all appeal? This paper sets out and evaluates a leading contemporary theory of possible worlds, David Lewis's Modal Realism. I note two competing ambitions for a theory of possible worlds: that it be reductive and user-friendly. I then outline Modal Realism and consider objections to the effect that it cannot satisfy these ambitions. I conclude that there is some reason to believe that Modal Realism is not reductive and overwhelming reason to believe that it is not user-friendly.

A major source of latter-day skepticism about necessity is the work of David Hume. Hume is widely taken to have endorsed the Humean claim: there are no necessary connections between distinct existences. The Humean claim is defended on the grounds that necessary connections between wholly distinct things would be mysterious and inexplicable. Philosophers deploy this claim in the service of a wide variety of philosophical projects. But Saul Kripke has argued that it is false. According to Kripke, there are necessary connections between distinct existences; in particular, there are necessary connections between material objects and their material origins. In this paper I argue that the primary motivation for the Humean claim, Hume's datum, also motivates the key premise in an argument for the necessity of origins. The very considerations that the Humean takes to show that necessary connections between wholly distinct things would be mysterious and inexplicable indicate that there must be some such necessary connections. Thus, in the absence of alternative support, there is no reason to believe the Humean claim.

Among the most remarkable developments in metaphysics since the 1950’s is the explosion of philosophical interest in possible worlds. This paper proposes an explanation of what possible worlds are, and argues that this proposal, the interpreted models conception, should be attractive to anyone who thinks that modal facts are primitive, and so not to be explained in terms of some non-modal notion of “possible world.” I articulate three constraints on any acceptable primitivist explanation of the nature of possible worlds, and show that the interpreted models conception meets the three constraints.

A standard view of reference holds that a speaker's use of a name refers to a certain thing in virtue of the speaker's associating a condition with that use that singles the referent out. This view has been criticized by Saul Kripke as empirically inadequate. Recently, however, it has been argued that a version of the standard view, a /response-based theory of reference/, survives the charge of empirical inadequacy by allowing that associated conditions may be largely or even entirely implicit. This paper argues that response-based theories of reference are prey to a variant of the empirical inadequacy objection, because they are ill-suited to accommodate the successful use of proper names by pre-school children. Further, I argue that there is reason to believe that normal adults are, by and large, no different from children with respect to how the referents of their names are determined. I conclude that speakers typically refer /positionally/: the referent of a use of a proper name is typically determined by aspects of the speaker's position, rather than by associated conditions present, however implicitly, in her psychology.

A compelling idea holds that reality has a layered structure. We often disagree about what inhabits the bottom layer, but we agree that higher up we find chemical, biological, geological, psychological, sociological, economic, /etc./, entities: molecules, human beings, diamonds, mental states, cities, interest rates, and so on. How is this intuitive talk of a layered structure of entities to be understood? Traditionally, philosophers have proposed to understand layered structure in terms of either reduction or supervenience. But these traditional views face well-known problems. A plausible alternative is that layered structure is to be explicated by appeal to explanations of a certain sort, termed / grounding explanations/. Grounding explanations tell us what obtains in virtue of what. Unfortunately, the use of grounding explanations to articulate the layered conception faces a problem, which I call /the collapse/. The collapse turns on the question of how to ground the facts stated by the explanations themselves. In this paper I make a suggestion about how to ground explanations that avoids the collapse. Briefly, the suggestion is that the fact stated by a grounding explanation is grounded in its /explanans/