The early David Lewis was a staunch critic of the Truthmaker Principle. To endorse the principle, he argued, is to accept that states of affairs are truthmakers for contingent predications. But states of affairs violate Hume's prohibition of necessary connections between distinct existences. So Lewis offered to replace the Truthmaker Principle with the weaker principle that ‘truth supervenes upon being’. This chapter argues that even this principle violates Hume's prohibition. Later Lewis came to ‘withdraw’ his doubts about the Truthmaker Principle, (...) invoking counterpart theory to show how it is possible to respect the principle whilst admitting only things that do not violate Hume's prohibition. What this really reveals is that the Truthmaker Principle is no explanatory advance on the supervenience principle. Extending Lewis's use of counterpart theory also allows us to explain away the necessary connections that threatened to undermine his earlier statements of supervenience. (shrink)

There is a long history of worrying about whether or not metaphysics is a legitimate philosophical discipline. Traditionally such worries center around issues of meaning and epistemological concerns. Do the metaphysical questions have any meaning? Can metaphysical methodology lead to knowledge? But these questions are, in my opinion, not as serious as they have sometimes (historically) been taken to be. What is much more concerning is another set of worries about metaphysics, which I take to the greatest threat to metaphysics (...) as a philosophical discipline. These worries, in effect, hold that the questions that metaphysics tries to answer have long been answered in other parts of inquiry, ones that have much greater authority. And if they haven’t been answered yet then one should not look to philosophy for an answer. What metaphysics tries to do has been or will be done by the sciences. There is nothing left to do for philosophy, or so the worry. Let me illustrate this with two examples, one of which is our main concern here. (shrink)

While many are impressed with the utility of possible worlds in linguistics and philosophy, few can accept the modal realism of David Lewis, who regards possible worlds as sui generis entities of a kind with the concrete world we inhabit.1 Not all uses of possible worlds require exotic ontology. Consider, for instance, the use of Kripke models to establish formal results in modal logic. These models contain sets often regarded for heuristic reasons as sets of “possible worlds”. But the “worlds” (...) in these sets can be anything at all; they can be numbers, or people, or sh. The set of worlds, together with the accessibility relation and the rest of the model, is used as a purely formal structure.2 One can even go beyond establishing results about formal systems and apply Kripke models to English, as Charles Chihara has recently argued.3 Chihara shows, for instance, how to use Kripke models (plus primitive modal notions) to give an account of validity for English modal sentences. In other cases worlds are not really needed at all. It is often vivid to give a counterexample thus: “There is a possible world in which P. Since your theory implies that in all worlds, not-P, your theory is wrong.” But the counterexample could just as easily be given using modal operators: “Possibly, P. Since your theory implies that it is necessary that not-P, your theory is wrong.”. (shrink)

General discussion of grounding, including its formal features, relations to other notions, and applications. (Originally published 2014; revised 2021).

How does metaphysical grounding interact with the truth-functions? I argue that the answer varies according to whether one has a worldly conception or a conceptual conception of grounding. I then put forward a logic of worldly grounding and give it an adequate semantic characterisation.

Counterpart theory has many benefits, but few are happy to accept the metaphysical setting in which this account of de re modality was developed by its architect, David Lewis. I argue here that counterpart theory can be made acceptable by the lights of those who repudiate the existence of merely possible objects. To the "ersatz" counterpart theorist I offer two stories: one about the relate of the counterpart relation and one about the relation itself. With these in place, I then (...) defend ersatz counterpart theory from a number of objections that can be found in the literature. (shrink)

Many contemporary philosophers endorse the Humean-Lewisian Denial of Absolutely Necessary Connections (‘DANC’). Among those philosophers, many deny all or part of the Humean-Lewisian package of views about causation and laws. I argue that they maintain an inconsistent set of views. DANC entails that (1) causal properties and relations are, with a few possible exceptions, always extrinsic to their bearers, (2) nomic properties and relations are, with a few possible exceptions, always extrinsic to their bearers, and (3) causal and nomic properties (...) and relations globally supervene on non-causal, non-nomic properties and relations. Hence, one can’t be a consistent Half-Hearted Humean. Consistency demands giving up the core Humean thesis or facing up to its consequences. The upshot is that we face a stark choice: either there are absolutely necessary connections between distinct existents or it’s "just one damn thing after another.". (shrink)

Counterpossibles are counterfactuals with necessarily false antecedents. The problem of counterpossibles is easiest to state within the "nearest possible world" framework for counterfactuals: on this approach, a counterfactual is true (roughly) when the consequent is true in the "nearest" possible world where the antecedent is true. Since counterpossibles have necessarily false antecedents, there is no possible world where the antecedent is true. On the approach favored by Lewis, Stalnaker, Williamson, and others, counterpossibles are all trivially true. I introduce several arguments (...) against the trivial approach. First, it is counter-intuitive to think that all counterpossibles are true. Second, if all counterpossibles were true, then we could not make sense of their use in logical, philosophical, or mathematical arguments. Making sense of the role of sentences like these requires that they not have vacuous truth conditions. The account of counterpossibles I ultimately favor is an extension of the "nearest possible world" semantics discussed above. The Lewis/Stalnaker account is supplemented with the addition of impossible worlds, and the nearness metric is extended to range over these impossible worlds as well as possible worlds. Thus, a counterfactual is true when its consequent is true in the nearest world where the antecedent is true; if the counterfactual's antecedent is impossible, then the nearest world in question will be an impossible world. Once the framework of impossible worlds and similarity is in place, we can put it to use in the analysis of other philosophical phenomena. I examine one proposal that makes use of a theory of counterpossibles to develop an analysis of the notion of metaphysical dependence. (shrink)

The topic of this study is the resemblance of individuals. The underlying contention of this dissertation is that the resemblance of individuals is a taxing and challenging philosophical topic. Two main claims are defended in this study to support this contention. The first of these claims is that resemblance is not a binary relation but a monadic multigrade property. The second of these claims is that the metaphysics of resemblance and the metaphysics of properties are distinct, although not independent, philosophical (...) issues. That resemblance is not binary but a monadic multigrade property makes resemblance taxing in at least two ways. First, resemblance is traditionally conceived of as a binary relation and on my account this traditional view is wrong. Second, a metaphysical account of multigrade properties is in itself a challenging issue. That the metaphysics of resemblance and the metaphysics of properties are distinct is motivated by the fact that an answer to the central question of the metaphysics of resemblance, which I identify as the question of whether the resemblance facts are context-relative, is not determined by any positioning on the central debate in the metaphysics of properties: the debate between the realist and the nominalist. Authors engaged in the realist/nominalist debate often address the central question of the metaphysics of resemblance in few words as their interest in resemblance is usually no more than an epiphenomenom of their interest in properties. It is one goal of this study to convince the reader that the central question of the metaphysics of resemblance needs to be addressed with more depth, and that addressing this question is challenging. (shrink)

Physicalists about the mind are committed to claims about property identities. Following Kripke's well-known discussion, modal arguments have emerged as major threats to such claims. This paper argues that modal arguments can be resisted by adopting a counterpart theoretic account of modal claims, and in particular modal claims involving properties. Thus physicalists have a powerful motive to adopt non-Kripkean accounts of the metaphysics of modality and the semantics of modal expressions.