ount of what an ability is, in the sense foregrounded at the outset. Subsidiary questions here include, for example, whether abilities may exist when they are unexercised, whether abilities are intrinsic or extrinsic features of their bearers, and whether agents have abilities in deterministic worlds. These are, broadly speaking, questions about the metaphysics of ability.
On the other hand, there are questions about ability-ascriptions. Abilities are characteristically ascribed (in English) with sentences involving the modal auxiliaries ‘can’ and ‘is able to.’ Accordingly, the central question here is to give a semantics for sentences involving those expressions. Subsidiary tasks include resolving certain open problems in the semantics of these expressions, such as the ‘actuality entailment’ observed in (Bhatt 1999), and integrating a semantics for agentive modals with a semantics for modal expressions more generally. These are, broadly speaking, questions about the semantics of agentive modality.
On certain conceptions of the philosophical enterprise, the project of giving a theory of ability and that of giving a semantics for ability-ascriptions are closely connected, and even collapse into each other. Nonetheless, there is at least a methodological distinction to be marked here. Having marked that distinction, this discussion will primarily be concerned with the first of these projects, the project of giving a theory of ability. Nonetheless, the project of giving a semantics for ability-ascriptions will also frequently be relevant. As with the distinction between general and specific abilities, this is for two reasons, one of coverage and one more properly philosophical.
The first reason, that of coverage, is the following. Many of the most prominent theories of ability defended in the philosophical literature have in fact been, in the first place, theories of ability-ascriptions. Indeed, the central thought in much work on ability in the analytic tradition has been a kind of semantic deflationism, on which we may give a semantics for ability-ascriptions that does not quantify over abilities themselves. This is arguably the main theme of the hypothetical theories to be considered in Section 3, and the modal theories to be considered in Section 4. Given this tendency in thinking about ability, an overview of philosophical work on ability that neglected the role of ability-ascriptions would be seriously incomplete.
There is also the second, more philosophical, reason. Any account of abilities owes us, among other things, an account of ability-ascriptions. This is perhaps true of philosophical topics generally, but it is true of ability in particular. Even philosophers who are explicit in their ‘refusal to take language as a starting point in the analysis of thought and modality’ (Lewis 1986, xi) are prone to make explicit appeal to language when the topic turns to ability, as occurs in (Lewis 1976) or (Taylor 1960). This is for any number of reasons, but perhaps especially because it is difficult to even identify the topic under consideration without using or mentioning certain phrases, notably ‘can’ and ‘is able to.’
Happily, the topic of ability-ascriptions is one on which linguists and philosophers have made significant progress. While there has long been considerable philosophical interest expressions such as ‘can’ and ‘is able to,’ there is nothing recognizable as a rigorous semantic theory of such terms prior to the foundational work of Angelika Kratzer, recently revised and collected in (Kratzer 2012). Kratzer’s work has been central to natural language semantics, and its significance for philosophical work is still being appreciated. The question of whether it is correct as an account of the semantics of agentive modality is an open one: important challenges include (Hackl 1998) and, more recently, (Mandelkern, Schultheis, and Boylan, 2017), (Schwarz 2020), and (Willer forthcoming). The Kratzer semantics, and a view of ability on which that semantics plays a foundational role, will be considered in some detail 