This paper surveys recent "new actualist" approaches to modality that do without possible worlds and locate modality squarely in the actual world. New actualist theories include essentialism and dispositionalism about modality, each of which can come in different varieties. The commonalities and differences between these views, as well as their shared motivations, are layed out.

Truthmakers, truth conditions, and analyses are closely related, but distinct in rather important ways. A failure to properly appreciate their differences has led to some confusion regarding the role that possible worlds ought to play with respect to modality. Those philosophers who initially proposed the existence of possible worlds were understood as providing an analysis of modality. More recently, many have interpreted them as providing modal truthmakers. But, possible worlds are only suited to serve as truth conditions for modal truths. (...) My goals are as follows: First, to dispel this confusion by detailing the differences between these three concepts. Second, to apply the lesson learned to the famous Humphrey objection against possible worlds. While this objection, if successful, does undermine Lewisian modal realism, it only partially undermines ersatzism, and leaves available a route by which ersatzers may avoid the objection altogether. (shrink)

Platonism delivers a theory of possibility that is distinct from both Lewisian modal realism and ersatz modal theories. By putting the topic of alien properties at centre stage in our modal theorizing, a strong preliminary case for platonism can be made. A puzzle about alien properties is created by modern truthmaker theory and some plausible assumptions about properties and existence. But this puzzle is one that platonism is able to solve in a simple and conservative way.

Possible worlds, concrete or abstract as you like, are irrelevant to the truthmakers for modality—or so I shall argue in this paper. First, I present the neo-Humean picture of modality, and explain why those who accept it deny a common sense view of modality. Second, I present what I take to be the most pressing objection to the neo-Humean account, one that, I argue, applies equally well to any theory that grounds modality in possible worlds. Third, I present an alternative, (...) properties-based theory of modality and explore several specific ways to flesh the general proposal out, including my favored version, the powers theory. And, fourth, I offer a powers semantics for counterfactuals that each version of the properties-based theory of modality can accept, mutatis mutandis. Together with a definition of possibility and necessity in terms of counterfactuals, the powers semantics of counterfactuals generates a semantics for modality that appeals to causal powers and not possible worlds. (shrink)

In this thesis, I develop a nonreductive and general conception of potentiality, and explore the prospects of a realist account of possibility based on this account of potentiality. Potentialities are properties of individual objects; they include dispositions such as fragility and abilities such as the ability to play the piano. Potentialities are individuated by their manifestation alone. In order to provide a unified account of potentialities, I argue in chapter 2 that dispositions, contrary to philosophical orthodoxy, are best understood in (...) terms only of their manifestations (as disposi- tions to ...), rather than in terms of a stimulus and a manifestation condition (as dispositions to ... if ...). Chapter 3 provides some preliminary motivation for a nonreductive and gen- eral account of potentiality, and chapter 4 develops such an account. The guiding question is how far the notion of potentiality can be extended from the initial ex- amples of familiar dispositions and abilities, and it is argued that it can be extended very far. Various features of potentialities are explored, among them extrinsicality, iterations of potentiality, and the behaviour of potentiality with regard to logical equivalence. In chapter 5, the account is set to work in providing the outlines and a defense of a potentiality-based account of possibility. The basic idea of such an account is that it is possible that p just in case some thing has a potentiality for p. The account is defended against the objection that there may not be enough potential- ities to ground all the possibilities that there are. Finally, in chapter 6, a logic of potentiality is formulated and the logic of possibility derived from it, showing that the potentiality-based account of possibility is formally adequate: it provides pos- sibility with the formal features that modal logicians have studied. I conclude that the proposed account of possibility is a promising research programme. (shrink)