## 1. A taxonomy



What *is* an ability? On one reading, this question is a demand
for a *theory* of ability of the sort described above. On
another reading, however, this question simply asks for a rough guide
to what *sort* of things we are speaking of when we speak of
'abilities'. So understood, this question is not asking
for a theory of ability, but for an explanation of what exactly a
theory of ability would be a theory *of*. This section will
offer an answer to this question on this second, more modest,
reading.


### 1.1 Dispositions and other powers



It will be helpful to begin by considering a topic that is related to,
but nominally distinct from, abilities: dispositions.



Dispositions are, at first pass, those properties picked out by
predicates like 'is fragile' or 'is soluble',
or alternatively by sentences of the form '*x* is
disposed to break when struck' or '*x* is disposed
to dissolve when placed in water.' Dispositions so
understood have figured centrally in the metaphysics and philosophy of
science of the last century (Carnap 1936 & 1937, Goodman 1954),
and also in influential accounts of the mind (Ryle 1949). They are
like abilities in many significant respects, in particular in the fact
that they are properties of things that can exist even when not
manifested: as a glass may be fragile even when it is not broken, so
may a person have the ability to raise her arm even when she is not
raising her arm.



While dispositions have been central to contemporary philosophical
discussions, they do not exhaust the range of the possibilities
inherent in things. Especially notable, for present purposes, are
those that are intimately connected to agency. These include the
susceptibility of things to be acted on in certain ways -- such
as the edibility of an apple, or the walkability of a trail --
that the psychologist J.J. Gibson called affordances (Gibson, 1979).
These include also the powers of action that we ascribe to things, of
the kind observed by Thomas Reid: 'Thus we say, the wind blows,
the sea rages, the sun rises and sets, bodies gravitate and
move' (Reid 1788/2010, 16; Reid himself regarded these locutions
as "misapplications" of active verbs, based on erroneous
views of the grounds of powers). Finally, and crucially, these include
the powers of agents themselves.



In light of this ontological diversity, it will be useful to have a
term that encompasses all the possibilities inherent in things and in
agents. Let us reserve the word 'power' for that general
class. Dispositions, as defined above, are a proper subset of powers
more generally. Affordances, as sketched above, are another one. And
abilities, in a sense still to be defined, are yet another.



It may yet be that dispositions are especially privileged among the
powers. For instance, they might be more fundamental than the other
powers, in the sense that other powers may be reduced to them. It has
been proposed, for instance, that affordances may be reduced to
dispositions (Scarantino 2003). And we will consider in some detail,
in Section 5.1, the proposal that abilities themselves may be reduced
to dispositions. But our initial hypothesis is that dispositions are
simply one member of the broader family of powers, albeit one that has
received a great measure of attention in the philosophical
literature.


### 1.2 Demarcating abilities



Abilities, then, are a kind of power. What kind of power, precisely,
is an ability? As the term will be understood here, there are two
additional conditions that a power must meet in order for it to be an
ability. First, abilities are distinguished by their subjects.
Abilities are properties of agents, rather than of things that are not
agents. Objects have dispositions and affordances -- as a glass
is disposed to break when struck, or affords the drinking of liquid
-- but they do not have abilities. Being a power of an agent is
not, however, a sufficient condition for being an ability. This is
because agents have powers that are not abilities. Therefore, second,
abilities need to be distinguished by their objects: abilities relate
agents to *actions*.



Some examples may make the need for this second condition clear. Some
powers, though properties of agents, do not intuitively involve any
relation to action. Consider the power of understanding language.
Understanding a sentence, while it is not wholly passive or arational,
is not typically an action. In contrast, speaking a sentence is. Thus
the power to understand French will not be an ability, on the present
taxonomy. In contrast the power to speak French will be an ability,
since it involves a relation to action. (See van Inwagen 1983,
8-13.)



So, as the term will be understood here, an ability is a power that
relates an agent to an action. This way of demarcating abilities,
while serviceable for our purposes, is not unproblematic. For it
inherits the problems involved in drawing the distinction between
actions and non-actions. First, there is the problem that the domain
of action is itself a contentious matter. Second, there is the problem
that, even if we have settled on an account of action, it is plausible
that the domain of action will be *vague*, so that there are
some events that are not definitely actions, but that are not
definitely not actions either. Arguably both of these points about
action apply, also, to the property of being an agent. If this is
right, then the present account of ability, which is cashed out in
terms of agency and action, will be correspondingly contentious and
vague. Borderline cases may, in the end, generate problems for the
theory of ability. But such problems will not be central here. For
giving such a theory will be difficult enough even when we focus on
paradigm cases of agency and action, and so on paradigm cases of
ability.



Note there is a similarity between the present category of ability, as
distinct from other powers, and the traditional category of active
powers, where active powers are those that essentially involve the
will (Reid 1788/2000). But it is not clear that these distinctions
overlap exactly. For example, the power to will itself will clearly be
an active power. It is less clear whether it will count as an ability,
for the answer to that question will turn on the contentious question
of whether willing is itself an action.


### 1.3 'Know how' and the intelligent powers



Some will expect that an account of ability would also be an account
of what it is to *know how* to perform an action, on the
supposition that one knows how to perform a certain action just in
case one has the ability to perform that action. This supposition,
which we may call the *Rylean* account of know how (since it is
most explicitly defended in Ryle 1949, 25-61), has been called
into question by Jason Stanley and Timothy Williamson (Stanley and
Williamson 2001). Let us briefly consider Stanley and Williamson's
argument and how it bears on the theory of ability.



Stanley and Williamson argue, on broadly linguistic grounds, that our
default view of know how ought to be rather different from Ryle's.
Part of the argument for this is that standard treatments of embedded
questions ('know who', 'know where', and so
forth; see Karttunen 1977) suggest a rather different treatment. On
this treatment, to know how to *A* is to know a certain
proposition. At first pass, in Stanley and Williamson's
presentation, for *S* to know how to *A* is for
*S* to know, of some contextually relevant way of acting
*w*, that *w* is a way for *S* to *A*.
Stanley and Williamson develop and defend such a treatment, and offer
independent considerations for rejecting Ryle's own arguments for
the Rylean view. On their view, then, to know how to *A* is
*not* to have an ability.



Stanley and Williamson's arguments are far from widely accepted
(see Noe 2005), but they tell at the very least against simply
*assuming* that an account of ability will also be an account
of know how. So we will leave questions of know how to one side in
what follows. It is also reasonable to hope that an account of
ability, while it may not simply *be* an account of know how,
will at least shed light on disputes about know how. For so long as we
lack a theory of what an ability is, the precise content of the Rylean
view (and of its denial) remains unclear. So it may be that getting
clear on abilities may help us, perhaps indirectly, to get clear on
know how as well. (Additional discussion of these questions may be
found in Stanley's book-length development of his and
Williamson's initial position (Stanley 2011), as well as the
papers collected in (Bengson and Moffett 2011).



Whatever our view of ability and know how, there is a further question
at the intersection of these topics that bears consideration. This is
how to accommodate those powers of agents that appear to be especially
closely connected to practical intelligence, such as skills and
talents -- which we might collectively call the *intelligent
powers*. Are the intelligent powers simply a species of ability,
or do they demand an independent treatment? There are a number of
recent proposals to be considered here. (Robb forthcoming) proposes a
dispositionalist theory of talent, on which a talent is a disposition
to maintain and develop a skill. (McGeer 2018) emphasizes the
significance of a distinctive kind of intelligent power, which she
(following Ryle) calls an 'intelligent capacity,' and of
which she too offers a broadly dispositionalist account. These
proposals suggest a more general program of dispositionalism about the
intelligent powers, which has suggestive parallels to the
dispositionalism about ability that we will consider in Section 5.1.
Still more generally, accurately accounting for the nature of the
intelligent powers, and the relationship of these to abilities and to
the powers more generally, remains an open and intriguing problem.


## 2. Two fundamental distinctions



If one wants to give a theory of ability of the sort described at the
outset, it is helpful for that theory to observe some formal
distinctions that have been marked in the literature. This section
canvasses two of the most important formal distinctions.


### 2.1 General and specific ability



The previous section was primarily concerned with distinguishing
abilities from other powers. But there is also a distinction to be
made within the class of abilities itself. This is the distinction
between *general* and *specific* abilities
(Honore 1964, Mele 2002).



The distinction between general and specific abilities may be brought
out by way of example. Consider a well-trained tennis player equipped
with ball and racquet, standing at the service line. There is, as it
were, nothing standing between her and a serve: every prerequisite for
her serving has been met. Such an agent is *in a position to*
serve, or has serving as an *option*. Let us say that such an
agent has the *specific ability* to serve.



In contrast, consider an otherwise similar tennis player who lacks a
racquet and ball, and is miles away from a tennis court. There is
clearly a good sense in which such an agent has the ability to hit a
serve: she has been trained to do so, and has done so many times in
the past. Yet such an agent lacks the *specific ability* to
serve, as that term was just defined. Let us say that such an agent
has the *general ability* to serve.



The concern of this article will be general abilities in this sense,
and unqualified references to 'ability' should be read in
that way. But specific abilities will also be at issue. This is for at
least two reasons.



The first is one of coverage: many of the proposals that are relevant
to the understanding of ability, especially the classical
'conditional analysis' (discussed in Section 3.1 below),
are naturally read as proposals about specific ability in the present
sense, and a suitably broad conception of ability lets us keep these
proposals within our domain of discussion.



The second reason is more properly philosophical. If we accept the
distinction between general and specific abilities, then we want for
our account of ability to accommodate both of them, and ultimately to
explain how they are related to each other. For this distinction is
not plausibly diagnosed as mere ambiguity; it rather marks off
something like two modes of a single kind of power. There are at least
two kinds of proposals one may make here. One, arguably implicit in
many of the 'new dispositionalist' approaches to ability,
is that general ability is in some sense prior to specific ability: to
have a specific ability is simply to have a general ability and to
meet some further constraint, such as having an opportunity. Another
proposal (suggested in Maier 2015) is that specific ability is in some
sense prior to general ability: to have a general ability is simply to
have a specific ability under a certain range of circumstances.



The idea that there is some sort of bipartite distinction to be made
between abilities has been a prominent theme in contemporary work on
ability. It has been endorsed and developed, in different contexts, by
Glick (2012), Vihvelin (2013), and Whittle (2010). It is an open
question whether the bipartite distinctions in ability introduced by
these authors are the same as one another, or the same as the one
introduced here. It could be that there are *several* bipartite
distinctions to be made in this area, or that we simply have one
distinction under several names.


### 2.2 Abilities and ability-ascriptions



Much philosophical discussion of ability has taken place in the
formal, as opposed to the material, mode. Thus we are often asked to
distinguish *senses* of 'ability', or to think
about what 'can' means. This subtle shift between
discussing ability and discussing the ascription of ability is often
harmless. Nonetheless, it is important to bear in mind the distinction
between these questions, and to mark this distinction explicitly at
the outset.



On the one hand, there are questions about ability itself. The central
question here to give an account 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 in Section 4. The more methodological point being made
here is that any adequate account of ability ought to provide an
account of ability-ascriptions, and as such may want to reckon with
this ongoing debate in the semantics of modal expressions.


## 3. Hypothetical theories of ability



The bulk of theories of ability that have been defended in the
historical and contemporary literature have been what we might call
*hypothetical* theories. On such views, to have an ability is
for it to be the case that one *would* act in certain ways if
one were to have certain volitions. One arrives at different theories
depending on how one understands the volitions in question and how
exactly these actions would hypothetically depend on them, but
nonetheless these views constitute something like a unified family.
Given their prominence and unity, it is natural to begin our survey of
theories of ability with them.


### 3.1 The conditional analysis



The most prominent hypothetical theory of ability is what has come to
be called the 'conditional analysis'. In this section, we
will survey that form of analysis, the problems for it, and
alternatives to it that are supposed to overcome those problems.



The conditional analysis of ability has at least two aspects. First,
*S* has an ability to *A* just in case a certain
conditional is true of her. Second, that conditional has the following
form: *S* would *A* if *S* were to have a certain
volition. The precise form such an analysis will take will depend on,
first, how we interpret this conditional and, second, which volition
figures in the antecedent.



It has been standard in the literature, when this first question has
been raised, to understand the conditional as a *subjunctive*
conditional (Ginet 1980), and we will assume in what follows that this
is the best form of the conditional analysis. There has been some
disagreement about whether it is a *might* or a *would*
conditional that is relevant (for an account of this distinction, see
Lewis 1973, 21-24), as well as about which volition is relevant.
In the following, we will take the relevant conditional to be a
*would* conditional, and the relevant volition to be
*trying*, though nothing will hang on these selections, and the
points to be raised would apply also to other forms of conditional
analysis, *mutatis mutandis*.



We thus arrive at the following form of the conditional analysis:



(CA)
*S* has the ability to *A* iff *S* would
*A* if *S* tried to *A*.




If (CA) were true, it would constitute a theory of ability in that it
would say under exactly what conditions some agent has the ability to
perform some action without making reference to the idea of ability
itself. (Note that a variant on (CA) that is sometimes discussed,
according to which *S* has the ability to *A* iff
*S* *could* *A* if *S* tried to
*A*, would not meet this standard, since the
'could' seems to make a claim about *S*'s
abilities. So such a view is not really a conditional
*analysis*. Indeed, it is not even clear that it involves a
genuine conditional, for reasons discussed in Austin 1970
(211-213).



The conditional analysis so understood has been subject to a fair
amount of criticism, which will be reviewed in the following section.
It bears noting, however, just how apt an account of ability it seems
at first pass. It satisfies, at least at first approximation, the
extensional constraints: there are many actions with respect to which
a typical agent satisfies the relevant conditional, and also many
actions with respect to which she does not, and these roughly
correspond to her abilities. This imposes a demand even on those who
wish to reject (CA), namely to explain *why*, if (CA) is simply
false, it so closely approximates to the truth about abilities.



Its approximate satisfaction of the extensional constraints is also
plausibly a reason why something like (CA) has found so many
thoughtful advocates. It is at least strongly suggested, for example,
by the following remarks from Hume's *Enquiry*:



> 
> For what is meant by liberty, when applied to voluntary actions? We
> cannot surely mean that actions have so little connexion with motives,
> inclinations, and circumstances, that one does not follow with a
> certain degree of uniformity from the other, and that one affords no
> inference by which we can conclude the existence of the other. For
> these are plain and acknowledged matters of fact. By liberty, then, we
> can only mean a power of acting or not acting, according to the
> determinations of the will; this is, if we choose to remain at rest,
> we may; if we choose to move, we also may. Now this hypothetical
> liberty is universally allowed to belong to every one who is not a
> prisoner and in chains. (8.1; Hume 1748, 72)
> 



Of course, Hume and many of those who have followed him have been
attempting to do something rather *more* than to offer a theory
of ability. Hume's intent was to show that disputes over
'question of liberty and necessity, the most contentious
question of metaphysics' have been 'merely verbal'
(8.1; Hume 1748, 72). Whatever we may think of this striking claim,
however, there is a dialectical gap between it and the alleged truth
of (CA). To anticipate a theme that will be central in what follows,
we must be careful to distinguish between, on the one hand, the
adequacy of various views of ability and, on the other, the more
contentious metaphysical questions about freedom to which they are
doubtlessly related. It is the former that will be our concern in this
section.


### 3.2 Problems for the conditional analysis



(CA) says that satisfying a certain conditional is both sufficient and
necessary for having a certain ability. There are two kinds of
counterexamples that may be brought against (CA): counterexamples to
its sufficiency, and to its necessity. Let us take these in turn.



Counterexamples to the *sufficiency* of (CA) have been most
prominent in the literature. Informally, they are suggested by the
question: 'but could *S* try to *A*?' There
are a variety of ways of translating this rhetorical question into a
counterexample. We may distinguish two: *global*
counterexamples, according to which (CA) might *always* get the
facts about ability wrong, and *local* counterexamples,
according to which (CA) might *sometimes* get the facts about
ability wrong.



Begin with global counterexamples. Let us say that
*determinism* is true at our world. Familiar arguments purport
to show that, if this is the case, then no one has the ability to do
anything, except perhaps for what she actually does (for several
developments of such an argument, see van Inwagen 1983, 55-105).
But if (CA) is true, then agents would have the ability to perform
various actions that they do not actually perform. For it is plausible
that the conditionals in terms of which (CA) analyzes ability would
still be true in a deterministic world. But then, since it makes false
predictions about such a world, which for all we know may be our own,
(CA) is false.



The difficulties involved in this sort of counterexample are clear.
The proponent of (CA) will reject the arguments for the
incompatibility of ability and determinism as unsound. Indeed, it is
precisely her thought that such arguments are unsound that has
typically led her to take ability to be analyzed in terms like those
of (CA). So global counterexamples, while they may be successful, are
*dialectically ineffective* relative to the range of questions
that are at issue in the debates over ability.



It seems, however, that we can show that (CA) is false even relative
to premises that are shared between various disputants in the free
will debates. This is what is shown by *local* counterexamples
to (CA). One such example is given by Keith Lehrer:



> 
> Suppose that I am offered a bowl of candy and in the bowl are small
> round red sugar balls. I do not choose to take one of the red sugar
> balls because I have a pathological aversion to such candy. (Perhaps
> they remind me of drops of blood and ... ) It is logically
> consistent to suppose that if I had chosen to take the red sugar ball,
> I would have taken one, but, not so choosing, I am utterly unable to
> touch one. (Lehrer 1968, 32)
> 



Such an example shows that (CA) is false without assuming anything
contentious in debates over freedom. It turns rather on a simple
point: that psychological shortcomings, just as much as external
impediments, may undermine abilities. (CA), which does not recognize
this point, is therefore subject to counterexamples where such
psychological shortcomings become relevant. We may, if we like,
distinguish 'psychological' from
'non-psychological' ability, and claim that (CA) correctly
accounts for the latter (this sort of strategy is suggested, for
example, by Albritton 1985). But our ordinary notion of ability, that
of which we are attempting to give a theory, seems to involve
*both* psychological and non-psychological requirements. And if
that is correct, then Lehrer's example succeeds as a
counterexample to (CA) as a theory of our ordinary notion of
ability.



Counterexamples to the *necessity* of (CA) have been less
frequently discussed (though see Wolf 1990), but they also raise
important issues about ability. Consider a case where a good golfer
misses an easy putt. Given that this golfer tried to make the putt and
failed to, it is false that she would have made the putt if she had
tried to; after all, she *did* try it and did not make it.
(This thought is vindicated by standard views of subjunctive
conditionals; see Bennett 2003, 239). But, as a good golfer, she
presumably had the ability to make the putt. So this seems to be a
case where one can have an ability without satisfying the relevant
conditional, and hence a counterexample to the necessity of (CA).



Here the defender of (CA) might avail herself of the distinction
between specific and general abilities. (CA), she might say, is an
account of what it is to have a specific ability: that is, to actually
be in a position to perform an action. The golfer *does* lack
this ability in this case, as (CA) correctly predicts. It is
nonetheless true that the golfer has the *general* ability to
sink putts like this. But (CA) does not purport to be an analysis of
general ability, and as such is compatible with the golfer having that
sort of ability. Again, the plausibility of this response will hang on
the viability of the distinction between specific and general
abilities.



We have seen that (CA) faces serious problems, especially as a
*sufficient* condition for ability, even once we set to one
side contentious claims about freedom and determinism. If this is
correct, then (CA) must either be modified or rejected outright. Let
us first consider the prospects for modification.


### 3.3 The conditional analysis: some variations



The guiding idea of hypothetical accounts is that abilities are to be
defined in terms of what someone would do were he in certain
psychological conditions. There are a number of ways of developing
this idea that do not fit into the form of (CA). At least two such
proposals deserve attention here.



Donald Davidson takes concerns about the sufficiency of (CA),
especially as developed in Chisholm 1964, to tell decisively against
it. More specifically, he takes the lesson of this problem to be is
that:



> 
> The antecedent of a causal conditional that attempts to analyze
> 'can' or 'could' or 'free to' must
> not contain, as its dominant verb, a verb of action, or any verb
> which makes sense of the question, Can someone do *it*?
> (Davidson 1980, 68)
> 



Davidson suggests that we may overcome this difficulty at least by
endorsing:



> 
> *A* can do *x* intentionally (under the description
> *d*) means that if *A* has desires and beliefs that
> rationalize *x* (under *d*), then *A* does
> *x*. (Davidson 1980, 68)
> 



Davidson proceeds to consider a number of further problems for this
proposal and for the causal theory of action generally, but he takes
it to suffice at least to overcome standard objections to the
sufficiency of (CA).



The trouble is that it is not at all clear it does so. For these
objections did not essentially depend on a verb of action figuring in
the antecedent of the analyzing conditional. Consider Lehrer's
case again. It seems true that *if* Lehrer's imagined agent
has desires and beliefs that rationalized that action under the
description 'eating a red candy'--namely, adopting
the analysis of Davidson 1963, a desire for a red candy and a belief
that this action is a way of eating a red candy--she would eat a
red candy. But the trouble is precisely that, in virtue of her
psychological disability, she is incapable of having this desire, and
so cannot perform this action intentionally. For this reason it does
not seem that Davidson's proposal successfully overcomes the
sufficiency problem, at least not on Lehrer's way of developing
that problem.



A second and rather different approach to modifying (CA) has been
taken in recent work by Christopher Peacocke. Peacocke accepts that
(CA) is insufficient in light of counterexamples like Lehrer's.
But he argues that we might *supplement* (CA) in order to
overcome these difficulties. In the terms of the present discussion,
Peacocke's proposal is: *S* has the ability to *A*
just in case: (i) (CA) is true of *S* *and* (ii) the
possibility in which *S* tries to *A* is a
'close' one. The closeness of a possibility as it figures
in (ii) is to be understood, at first pass, in terms of what we can
reasonably *rely on*: a possibility is a distant one just in
case we can reasonably rely on it not obtaining; otherwise it is a
close one (Peacocke 1999, 310). To modify one of Peacocke's
examples, the possibility of toxic fumes being released into a train
car that is safely insulated is a distant one; on the other hand, the
possibility of toxic fumes being released into a train car where they
just happen to be blocked by a fortuitous arrangement of luggage is a
close one.



Peacocke's thought is that this suffices to overcome the
sufficiency objection: though Lehrer's agent satisfies (i), she
does not satisfy (ii): given the facts about his psychology, the
possibility that he tries to *A* is not a close one. The
trouble, however, is that Peacocke's proposal is subject to
modified versions of Lehrer's counterexample. Consider an agent
whose aversion to red candies is not a permanent feature of her
psychology, but an unpredictable and temporary 'mood'.
Consider the agent at some time when she is in her aversive mood. This
agent satisfies (i), for the same reason as above, and she also
satisfies (ii): given the fragility of her mood, the possibility of
her trying is a close one in the relevant sense. Yet such an agent
lacks the ability to eat a red candy, in precisely the same way as she
does in Lehrer's original example.



It is an interesting question how we might develop other
'supplementation' strategies for (CA) (such strategies are
also suggested by Ginet 1980), though the track record of this method
of analysis in other domains (for instance, the project of
'supplementing' the analysis of knowledge in terms of
justified true belief, in response to (Gettier 1963)) does not inspire
confidence.


## 4. Modal theories of ability



There is a surprising disconnect between the way abilities have been
discussed in the philosophical literature in the tradition of Hume and
the way that they have been approached in more recent work in logic
and linguistics. Here, ability claims are understood as categorical
possibility claims: claims about what some agent does in some
non-actual state of affairs (or 'possible world'). Let a
*modal theory of ability* be any theory on which claims about
an agent's abilities are understood in terms of claims about
what that agent in fact does at some possible world (or set of
worlds). The idea that some such modal theory of ability must be true
is a presumption of much formal work on ability and
ability-ascriptions. Yet there are serious challenges to the idea that
ability is in this sense a modality.


### 4.1 The modal analysis



Intuitively, claims about ability are claims about possibility. It is
in some sense a truism that someone is able to perform some act just
in case it is possible for her to perform it.



To develop this purported truism, begin with the thought that for
*S* to have an ability to *A* it is necessary, but not
sufficient, that it be possible that *S* does *A*. This
claim will be contentious for various more specialized sorts of
possibility, such as *nomic* possibility. But if we may help
ourselves to the idea of possibility *simpliciter*
('metaphysical possibility,' on at least one reading
of that phrase), then this claim appears plausible. (We will survey
some historical and contemporary challenges to it below in Section
4.2.) On the other hand it seems implausible that this sort of
possibility is a sufficient condition: there are any number of acts
that that are metaphysically possible to perform that an agent might
nonetheless not be able to perform.



This suggests a natural hypothesis. To have an ability is for it to be
possible to *A* in some *restricted* sense of
possibility. As nomic possibility is possibility relative to the laws
of nature, and epistemic possibility is possibility relative to what
an agent knows, so may ability be possibility relative to some
independently specifiable set of conditions.



To render this hypothesis precisely, we may help ourselves to the
formal framework of 'possible worlds,' which offers an
elegant and powerful semantics for modal language. On this framework,
a proposition is possible just in case it is true at some possible
world. We can then say an agent is able to *A* just in case she performs
that act at some world (or set of worlds) that satisfy some
independently specifiable set of conditions.



We thus arrive at the modal analysis of ability:



(MA) *S* has the ability to *A* iff *S*
does *A* at some world (or set of worlds) satisfying condition
*C*.




(MA) is actually not itself an analysis but rather a template for a
general family of analyses. Different members of this family will be
distinguished by the different candidates they might propose for *C*, as
well as whether they quantify over individual worlds or sets of
worlds. Nonetheless, these analyses demonstrate sufficient theoretical
unity that they may be viewed, at an appropriate level of abstraction,
as a single approach to the analysis of ability.



Two points about (MA) bear noting. First, 'modal' here is
being used in a relatively strict and narrow way. Sometimes
'modal' is used loosely to describe phenomena that are
connected to possibility (and necessity) in some way or other. As
noted above, it is a truism that there is some connection between
ability and necessity, and so that ability is in this loose sense
'modal.' The proponent of (MA) is concerned with modality
in a stricter sense: she proposes that ability may be analyzed in
terms of the precise framework of propositions and possible worlds
just adumbrated. The opponent of (MA), in turn, grants that ability
has something to do with possibility but denies that any such analysis
succeeds.



Second, while (MA) has been presented as an alternative to (CA), (CA)
is arguably just one particular version of (MA). For, as noted above,
(CA) appeals to a subjunctive conditional, and the standard semantics
for the subjunctive conditional (developed in slightly different ways
in Stalnaker 1968 and Lewis 1973) is told in terms of quantification
over possible worlds. Specifically (on Stalnaker's version) a
subjunctive conditional is true just in case its consequent is true at
the world where its antecedent is true that is otherwise maximally
similar to the actual world. In these terms, (CA) is roughly
equivalent to the following:



> 
> (CAmodal) *S* has the ability to *A*
> iff *S* does *A* at a world at which *S* tries
> to *A* that is otherwise maximally similar to the actual world.
> 



This is patently a version of (MA), with '*S* tries
to *A* and is otherwise maximally similar to the actual
world' serving as condition *C*.



If this is correct, then most discussions of the analysis on ability
in the twentieth century have focused on a special and somewhat
idiosyncratic case of a much broader program of analysis, namely the
program of giving a modal analysis of ability. The considerations
brought forth in the remainder of this section, in contrast, are
concerned with the general case.


### 4.2 The modal analysis: logical considerations



There are two questions that might be raised for this proposal about
ability. First, does ability indeed admit of some kind of modal
analysis? Second, if it does, how exactly are we to spell out the
details of that analysis -- in particular, how are we to
articulate condition C? Let us begin with the first, more basic,
question.



According to (MA), performing an act at some possible world (or set of
worlds) is both necessary and sufficient for having the ability to
perform that act. One way of challenging this claim is to deny the
necessity claim: that is, to argue that it is sometimes the case that
an agent is able to perform an act that she does not perform at any
possible world.



This is an argument that has in fact been made by several authors.
Descartes, for one, appears to have argued that God is such an agent
(Curley 1984). A genuinely omnipotent being, one might argue, should
be able to perform any act whatsoever, even the impossible ones. This
view of omnipotence is contentious, but it is not clear that it should
be ruled out formally, by the very analysis of ability, as (MA) does.
Spencer (2017) argues that even non-omnipotent agents may sometimes
have the ability to perform acts that they do not perform at any
possible world.



Let us grant, however, that the possibility of performing an act is a
necessary condition for performing that act, and that in this sense an
attribution of ability entails a possibility claim. One might
nonetheless resist the view that ability admits of a modal analysis in
the manner suggested by (MA).



That is the kind of argument developed in a prescient discussion by
Anthony Kenny (Kenny 1975; the presentation of Kenny here is indebted
to the discussion in Brown 1988). Kenny argues that, if something like
(MA) is indeed true, then ability should obey the principles that
govern the possibility operator in standard modal logics. Kenny claims
that ability fails to satisfy the following two principles:



(1) \(A \to \Diamond A.\)




Informally, (1) expresses the principle that if an agent performs an
action, then she has the ability to perform this action. This is,
Kenny argues, false of ability.



(2) \(\Diamond(A \lor B) \to (\Diamond A \lor \Diamond B).\)




Informally, (2) expresses the principle that if an agent has the
ability to perform one of two actions, then she has the ability to
perform either the first action or the second action. This is, Kenny
argues, false of ability.



Let us begin with (1). Kenny claims that this principle is false in
light of cases like the following: 'A hopeless darts player may,
once in a lifetime, hit the bull, but be unable to repeat the
performance because he does not have the ability to hit the
bull' (Kenny 1975, 136). This kind of 'fluky
success' has been extensively discussed in the philosophical
literature -- perhaps most famously in Austin (1956) -- in
order to make a variety of points. Kenny's insight is to observe
that these simple cases tell against the modal analysis of ability, as
they violate an axiom of many modal logics, namely any system as
strong as the system **T**.



A simple response to this point is to deny that **T** (or
any stronger logic) is the correct logic for ability. To deny this is
still to allow for a treatment of ability within the framework of
possible worlds. Notably, the modal logic **K** is one
that fails to validate (1). A natural response to Kenny's first
point, then, is to say that **K**, rather than
**T** or some stronger system, is the correct modal logic
of ability.



This response is not available, however, in response to Kenny's
second objection. Recall that objection was that (2) is true of
possibility but not of ability. Here the retreat to weaker modal
logics will not work, since (2) is provable on the weakest standard
modal logic, namely **K**. Yet the parallel claim does
not seem true of ability. Kenny gives the following example:



> 
> Given a pack of cards, I have the ability to pick out on request a
> card which is either black or red; but I don't have the ability to
> pick out a red card on request nor the ability to pick out a black
> card on request. (Kenny 1975, 137)
> 



This then appears to be a case where *S* has the ability to
*A* or *B* but lacks the ability to *A* and lacks
the ability to *B*. So it appears that (2) is false of ability.
In light of this Kenny concludes that 'if we regard possible
worlds semantics as making explicit what is involved in being a
possibility, we must say that ability is not any kind of
possibility' (Kenny 1975, 140).



To appreciate Kenny's conclusion, it is instructive to work
through why precisely this is a counterexample to (MA). Consider an
agent *S* who has the ability to pick a red card or a black
card, but does not have the ability to pick a red card or the ability
to pick a black card. According to (MA), *S* has the ability
to *A* iff *S* does *A* at some world (or set of
worlds) satisfying condition *C*. Consider the case where (MA)
appeals to a single world, not a set of worlds. If *S* has the
ability to pick a red card or pick a black card, then by (MA) there is
a world *w* satisfying condition *C* where *S*
picks a red card or black card. Then either *S* picks a red
card at *w* or *S* picks a black card
at *w*. Then, applying (MA) now in the other
direction, *S* has the ability to pick a red card or *S*
has the ability to pick a black card. But that, by assumption, is not
the case. Since (MA) is the only substantive premise appealed to that
argument, (MA) must be rejected.



Note that this argument turned essentially on adopting the version of
(MA) which appealed to a single world, rather than a set of worlds. So
one way of responding to this objection is by appealing to sets of
worlds in the modal analysis of ability. This is precisely the
proposal of Mark Brown, who argues that, if we take accessibility
relations to hold between a world and a set of worlds, then we
may capture talk of ability within a possible worlds framework that is
broadly in the spirit of standard views (Brown 1988; see also Cross
1986). Alternatively, we may take this sort of point to militate in
favor of a return to hypothetical theories of ability, since, at least
on Lewis's view of subjunctive conditionals, it may be that a
disjunction follows from a counterfactual claim without either of its
disjuncts following from that claim (Lewis 1973, 79-80). Modal
accounts that appeal to sets of worlds are 'non-normal' in
the sense that they do not satisfy the axiom **K**, but
they remain true to the letter of (MA) as well as the spirit of modal
analyses generally, insofar as they avail themselves only of possible
worlds and quantification thereover.


### 4.3 The modal analysis: linguistic considerations



In the material mode, the modal analysis gives an account of what it
is to have an ability in terms of quantification over possible worlds.
In the formal mode, it gives a semantics for the ascription of ability
-- paradigmatically, sentences involving 'can' or
'is able to' -- in terms of quantification over
possible worlds.



This formal aspect of the modal analysis has been prominent in the
philosophical and linguistic literature because the standard semantics
for ability ascriptions is an explicitly modal one. This is the view
developed in a series of papers by Angelika Kratzer (Kratzer 2012).
Kratzer treats expressions such as '*S*
can *A*' and '*S* is able
to *A*' as possibility claims. That is, '*S*
is able to *A*' is true just in case there is a possible
world *w* meeting certain conditions at which *S*
does *A*. The conditions are that (i) *w* be accessible
given some contextually-specified set of facts (the
*modal base*) and (ii) that *w* be at least as good,
according to a contextually-specified ranking of worlds
(the *ordering source*), as any other accessible world. The
Kratzer semantics is thus an instance of the modal analysis on its
semantic formulation:



> 
> (MAsemantic) '*S* is able to *A*'
> is true iff *S* does *A* at some world (or set of
> worlds) satisfying condition *C*.
> 



A number of objection have been brought against the modal analysis in
this latter, formal, aspect.



One objection prominent in the recent literature (Mandelkern et al.
2017; Schwarz 2020) is that Kratzer's semantics, or any analysis
of the form of (MAsemantic), appears to have trouble
marking an intuitive distinction between what someone is able to do
and what it is possible for her to do. Let us say that an unskilled
darts-player is about to throw a dart. She utters:



> 
> (3) I am able to hit the bullseye
> 



Intuitively, what she says is false: she is not able to hit the
bullseye, as she is a poor darts-player. Yet there is an accessible
and perfectly good possible world *w* at which she hits the
bullseye -- which is just to say, in the object language, that it
is possible for her to hit the bullseye.



This case suggests the Kratzer semantics lacks the resources to
capture the distinctively agentive force of a sentences such as (3).
There are, in addition, a number of other outstanding empirical
problems for Kratzer's semantics for ability modals. One is the
problem of accounting for 'compulsion' modals such as
'I cannot but tell the truth' (Mandelkern et al. 2017).
Another is that of accommodating the 'actuality
entailment' whereby, in many languages, certain ability
sentences entail that the act in question was actually performed
(Bhatt 1999; see also Hacquard 2009). Whatever our verdict on
(MAsemantic), the semantics of ability-ascriptions remains
an unresolved and potentially rich issue at the boundary of
linguistics and the philosophy of action.


## 5. New approaches to ability



The foregoing has indicated serious concerns about the adequacy of the
orthodox approaches to ability and its ascription: the conditional
analysis (CA), and the modal analysis (MA), of which (CA) is arguably
just a special case. This raises the question of what a
non-hypothetical and non-modal account of ability and its ascription
might look like.



Since abilities are, as noted in Section 1.1, a kind of power, one
natural idea is to analyze abilities in terms of some other kind of
power. This appeal may proceed in different ways. One is by appealing
to dispositions, and by analyzing abilities in terms of this
purportedly better-understood kind of power. Another is by departing
more radically from the standard ontology of recent metaphysics, and
analyzing ability in terms of some new and distinctive variety of
power. We will consider these approaches in turn in Sections 5.1 and
5.2. Finally, in Section 5.3, we will turn to miscellaneous
alternative approaches to ability, which reject the conditional and
modal analyses, but which do not purport to analyze abilities in terms
of powers either.


### 5.1 The 'new dispositionalism'



In recent years several authors have revisited the thought that we may
give a broadly hypothetical account of ability, without endorsing the
problematic claim (CA). This is the view of ability that has been
defended by Smith (2003), Vihvelin (2004, 2013), and Fara
(2008). Following Clarke (2009), we may label this view the
'new dispositionalism.'



What unifies the new dispositionalists is that they return to the
conditional analysis of ability in light of two thoughts. The first
thought is one already noted: that there is a variety of power,
dispositions, that is similar in many respects to abilities. The
second thought is that there are well-known problems of giving a
conditional analysis of *dispositions*, in light of which many
authors have been inclined to reject the long-assumed link between
dispositions and conditionals. Taken together, these thoughts yield a
promising new line on abilities: that though we ought to reject the
conditional analysis of abilities, we may yet defend a
*dispositional* account of abilities.



Why ought we reject the conditional analysis of dispositions? Consider
the following analysis of the disposition to break when struck:



> 
> (CD) *x* is disposed to break when struck iff *S* would
> break if *S* were struck.
> 



Despite the intuitive appeal of (CD), there appear to be at least two
kinds of counterexamples to it. First, consider a crystal glass that,
if it were about to be struck, would transform into steel. This glass
is disposed to break when struck, but it is not true that it would
break if struck--the transformation renders this false. This is a
case of *finking*, in the language of Martin 1994. Second,
consider a crystal glass stuffed with styrofoam packaging. This glass
is disposed to break when struck, but it is not true that it would
break if struck--the packaging prevents this. This is a case of
*masking*, in the language of Johnston 1992. In light of such
cases, it seems we ought to reject (CD).



The bearing of these points on our earlier discussion of the
conditional analysis is the following. There appear to be quite
*general* problems for giving a conditional analysis of powers.
So it may be that the failures of the conditional analysis of ability
were not due to any fact about abilities, but rather to a shortcoming
of conditional analyses generally. One way of overcoming this problem,
if this diagnosis is correct, is to analyze abilities directly in
terms of dispositions.



Such an analysis is proposed by Fara 2008, who argues:



> 
> *S* has the ability to *A* in circumstances *C*
> iff she has the disposition to *A* when, in circumstances
> *C*, she tries to *A*. (Fara 2008, 848)
> 



The similarity of this analysis to the hypothetical analyses canvassed
earlier are clear. This raises several immediate questions, such as
whether this analysis can overcome the problem of sufficiency that
plagued those approaches (see Fara 2008, 851-852 for an
affirmative answer, and Clarke 2009, 334-336 for some doubts).
What is most striking about the new dispositionalists, however, is how
they bring this sort of account of ability to bear on certain familiar
cases.



Consider how the new dispositionalism bears on so-called
'Frankfurt cases.' These are cases due to Frankfurt
1969, where an agent chooses to and performs some action *A*
while at the same time there is some other action *B* such
that, had the agent been about to choose *B*, an
'intervener' would have altered the agent's brain so
that the agent would have chosen, and performed, *A* instead.
One question about such cases is whether the agent, in the actual
sequence of events, had the ability to *B*. Frankfurt's
intuition, and that of most others, is that she did not. Given the
further claim that the agent is nonetheless morally responsible for
doing *A*, this case appears to be a counterexample to the what
Frankfurt calls the Principle of Alternative Possibilities (PAP): an
agent is morally responsible for *A*ing only if she had the
ability to perform some action other than *A*.



The new dispositionalists disagree. Let us focus on Fara's
diagnosis of the case. The question of whether the agent had the
ability to *B* turns, for Fara, on the question of whether she
was disposed to *B* when she tried to *B*. Fara
claims that she *does* have such a disposition. The
presence of the intervener is, on Fara's view, like the
aforementioned styrofoam packaging in a crystal glass. It
*masks* the disposition of the glass to break when struck, but
does not *remove* that disposition. Similarly, Fara argues, the
presence of the intervener *masks* the agent's disposition
to *B* when she tries to *B*, but does not
*remove* that disposition. (There is some disagreement among
the new dispositionalists about whether this is a case of finking or
masking; see Clarke 2009, 340 for discussion). So, *pace*
Frankfurt, the agent does have the ability to *B* after all.
And so we have, in this case at least, no counterexample to PAP.



A natural worry at this point is that the new dispositionalist has
simply *changed the subject*. For it seems clear that, in
a perfectly ordinary sense of ability, Frankfurt's agent
*lacks* the ability to do otherwise. An account of ability
which denies this seems to be speaking of some other concept
altogether. One way of bringing out what is missing is the idea that
there seems to be a connection between my abilities, in the sense of
ability that is relevant to free will, and what is *up to me*.
Clarke claims that this sort of connection fails on the new
dispositionalist view of ability:



> 
> Although the presence of a fink or mask that would prevent one's
> *A*ing is compatible with having a general capacity (the
> unimpaired competence to *A*), there is an ordinary sense in
> which in such circumstances an agent might well be unable to
> *A* ... If there is something in place that would prevent
> me from *A*ing should I try to *A*, if it is not up to
> me that it would so prevent me, and if it is not up to me that such a
> thing is in place, then even if I have a capacity to *A*, it is
> not up to me whether I exercise that capacity. (Clarke 2009, 339)
> 



Thus the objection is that, while the new dispositionalist has perhaps
offered a theory of *something*, it is not a theory of
ability.



How should the new dispositionalist respond? One thought is that we
are here again encountering the distinction between general and
specific abilities. The new dispositionalist might contend that, while
the agent in a Frankfurt case may lack the specific ability to do
otherwise, she has the general ability to do otherwise, and that it is
this general ability of which the new dispositionalist is giving an
account.



This response, however, postpones a crucial and much broader question.
The question is this: should 'ability' in (PAP) be
understood as general ability, or specific ability? If general ability
is what matters, then Frankfurt cases may indeed not tell against
(PAP), for the agent retains the general ability to do otherwise. If
it is specific ability that matters, however, the challenge to
(PAP) stands (see also Whittle 2010). This is a vital question for
understanding the purported connection between agents' abilities
and questions of moral responsibility, whatever our verdict on new
dispositionalism itself. (See Cyr and Swenson 2019 for a helpful
recent discussion of these issues).


### 5.2 Abilities as distinctive powers



As noted in Section 1.1, dispositions are simply one member of the
broader family of powers, albeit one that has figured prominently in
recent metaphysics. An alternative account of abilities might give an
account of abilities in terms of some other kind of power, perhaps one
better-suited to the distinctive aspects of abilities.



One account of this kind is developed in a series of works by Barbara
Vetter (especially Vetter 2015). Vetter proposes that our basic modal
notion should be *potentiality*. On a traditional view (which
Vetter rejects) dispositions involve a dyadic relation between a
stimulus and a manifestation (for example: a glass is disposed to
break when struck). In contrast, potentials involve a monadic relation
to a manifestation (for example: a glass has the potential to break).
This makes potentials especially well-suited to give an account of
abilities, which also appear to involve a monadic relation to an act,
namely the act denoted by the complement of an ability-ascription (for
example: I am able to play tennis). To have an ability, Vetter argues,
is simply to have a certain kind of potentiality. Vetter also provides
an explicit semantics for agentive modality in terms of the ascription
of potentiality (Vetter 2013), which constitutes a systematic
alternative to (MA).



Yet another view is suggested by recent work by Helen Steward
emphasizing the traditional idea of a 'two-way power'
(Steward 2012, Steward 2020; see also Alvarez 2013). Steward argues
that actions are exercises of two-way powers -- 'powers
which an agent can exercise or not at a given moment, even holding all
prior conditions at that moment fixed' (Steward 2020, 345).
These are to be contrasted with one-way powers, which manifest
whenever their manifestation conditions are realized, as a fragile
glass breaks whenever it is struck. Unlike both the new
dispositionalists on the one hand and Vetter on the other, Steward
sees a fundamental asymmetry between agents, who are bearers of
two-way powers, and mere objects, who are are bearers only of one-way
powers. It is natural then to think that what it is to have an ability
is to have a two-way power of a certain kind, and that a theory of
ability should follow from an account of agency and the two-way
powers.



We thus have at least three 'power-based' views of
abilities: the new dispositionalism, Vetter's potentiality-based
view, and Steward's two-way power-based view. It is instructive
to consider how these three accounts differ with respect to two larger
philosophical projects.



One is the project of giving an analysis of modal language, including
ability-ascriptions, in terms of possible worlds. The new
dispositionalist rejects (CA) and (MA) but she is still, in principle,
sympathetic with that project, insofar as she allows that disposition
ascriptions themselves may be ultimately understood in terms of
quantification over possible worlds. This kind of view is explicitly
endorsed, for instance, by Smith (2003). In contrast, Vetter is
explicitly opposed to this project, while Steward's view appears
neutral on this question.



Another is the project of arguing that agents' abilities are, or
are not, compatible with the possibility of determinism. This is a
question we touched on briefly in Section 5.1. As noted there, the new
dispositionalists are motivated, in part, by the project of arguing
for compatibilism. In contrast, Steward is explicitly concerned to
defend incompatibilism. (Vetter appears to be neutral on this
question.) The question of how the analysis of ability bears on the
free will debates looms over many of these discussions, and we will
confront it directly and at some length below in Section 6.


### 5.3 Other approaches



Still other approaches to ability reject (CA) and (MA) while rejecting
also the thought that some appeal to power -- be it a
disposition, a potentiality, or a two-way power -- is needed to
account for abilities.



One recurrent thought is that, despite the various challenges that
have been brought against it, ability is still intimately connected to
some kind of relation between an agent's volitions (tryings,
intendings) and her actions. One semantically sophisticated
development of this thought is Mandelkern et al, 2017, which proposes
to take as basic a notion of 'practically available
actions,' and to develop in terms of these a semantics for
agentive modality, one on which conditionals linking volitions to
actions continue to play an essential role. Another approach, in a
recent book-length treatment of ability (Jaster 2020), proposes that
abilities should be thought of in terms of proportions of cases where
an agent successfully does what she intends to do (compare the
approach to dispositions advocated in Manley and Wasserman 2008). Both
of these approaches are explicit in their denial of (CA), but they
share -- with the new dispositionalists -- the thought that
the analysis of ability should somehow appeal to a pattern of
dependence between volition and action.



This is not surprising. The conditional analysis is a redoubtable
proposal, endorsed by many of the major figures in English-language
philosophy. In light of that, it seems reasonable to try to discard
the letter of (CA), but retain its spirit. For it may be that the
historical failure of (CA) is due to difficulties and oversights that
our perhaps firmer grasp of technical issues allows us to overcome.
This is a sensible and well-motivated project, though it remains to be
seen whether it will be, in the end, a successful one.



There remain still other accounts that do not fit easily into the
taxonomy provided here. These include primitivist proposals, which
take ability or some closely related notion as analytically
fundamental. One development of this idea is Maier 2015, who proposes,
contrary to most authors, that specific ability is fundamentally prior
to general ability. He argues that we should give an account of
general ability in terms of specific abilities, which he calls
'options': roughly, an agent has the general ability to A
iff she normally has A as an option. Options, in turn, are primitives.
Much here will hang on saying more about options, and in what sense
they figure as primitives in the theory of agency.



Finally, an outline of a proposal by David Lewis (dated to 2001 but
only recently published as Lewis 2020) offers an altogether different
approach to ability. Lewis is motivated, like many proponents of (CA),
by the goal of defending compatibilism, but he takes (CA) to be
unsatisfactory. He therefore proposes a non-conditional analysis of
ability. His analysis, roughly, is that *S* has the ability to
perform an action *B* just in case there is some basic
action *A* such that (i) *S*'s doing *A*
would cause or constitute *S*'s doing *B* and (ii)
there is no obstacle to *S*'s doing *A*. The
problem of giving a theory of ability then becomes the problem of
giving a theory of obstacles, something at which Lewis, in his
outline, makes a beginning. (See Beebee et al 2020 for
additional discussion).



Lewis's proposal is an inspiration for further research in at
least two ways. First, it indicates that Lewis, a systematic philosopher of modality, saw the
problem of giving an analysis of ability as a significant outstanding
project. Second, it demonstrates that genuinely novel approaches to
ability remain available, and the project of giving a theory of
ability may yet be in its early stages.


## 6. Abilities and the free will debates



Thus far our questions about abilities have been formal ones: we have
been asking what it is to have an ability without concerning ourselves
with the substantive work that a theory of ability might have to do.
But there is much work to be had for a theory of ability: abilities
have figured as unexplained explainers in a range of philosophical
theories, for example in accounts of concepts (Millikan 2000), of
knowledge (Greco 2009, Sosa 2007), and of 'knowing what it's
like' (Lewis 1988). Perhaps the most prominent substantive role
for a theory of ability has been the uses to which accounts of
ability have been put in the free will debates. So let us close with a
brief survey of what work a theory of ability might be expected to do
in those debates.



Questions about abilities have figured most prominently in debates
over compatibilism. 'Compatibilism' is used in many ways,
but let us understand it here as the thesis that the ability to
perform actions one does not perform is compossible with the truth of
determinism, which we may take to be the view that the facts about the
past and the laws jointly determine the facts about the present and
all future moments. (We should sharply distinguish this view, which we
might call *classical compatibilism*, from more recent views
such as the 'semi-compatibilism' of Fischer and Ravizza
1998). Insofar as compatibilism, so understood, has been explicitly
defended, these defenses have made appeal to theories of ability,
notably the conditional analysis and its variants, as well as the
dispositionalist analysis favored by the new dispositionalists.



In the discussion of the conditional analysis, we distinguished
between *global* and *local* counterexamples to
hypothetical theories of ability, where the former appealed to the
fact that any such theory would render ability compatible with
determinism which, according to the objector, it is not. There we
noted the dialectical limitations of such counterexamples, namely the
contentiousness of their main premise. But compatibilists have often
been guilty of what seems to be the opposite mistake. Namely, they
have offered theories of ability which show abilities to be compatible
with determinism, and have argued *from* this to the claim that
such abilities are indeed compatible with determinism.



The shortcomings of this strategy are nicely diagnosed by Peter van
Inwagen. After surveying the local counterexamples that arise for
various hypothetical theories of ability, van Inwagen imagines that we
have arrived at the best possible hypothetical theory of ability,
which he labels 'the Analysis'. van Inwagen then
writes:



> 
> What does the Analysis do for us? How does it affect our understanding
> of the Compatibility Problem? It does very little for us, so far as I
> can see, unless we have some reason to think it is *correct*.
> Many compatibilists seem to think that they need only present a
> conditional analysis of ability, defend it against, or modify it in
> the face of, such counter-examples as may arise, and that they have
> thereby done what is necessary to defend compatibilism. That is not
> how I see it. The particular analysis of ability that a compatibilist
> presents is, as I see it, simply one of his premisses; his central
> premiss, in fact. And premisses need to be defended. (van Inwagen
> 1983, 121)
> 



van Inwagen's point is that, provided the incompatibilist has
offered *arguments* for the claim that such abilities are
incompatible with determinism--as, in van Inwagen's
presentation, the incompatibilist has--the production of an
analysis is as yet no answer to those arguments. For those arguments
are also arguments, *inter alia*, against the
compatibilist's favored account of ability.



There are, then, several obstacles for the compatibilist who wishes to
appeal to an account of ability in defense of compatibilism. First,
there is the general difficulty of actually giving an extensionally
adequate theory of ability. In addition, we have now turned up a
couple of more specific challenges to the compatibilist. There is van
Inwagen's point just outlined, namely that arguments for the
incompatibility of abilities and determinism are, *inter alia*,
arguments against any theory of ability that is congenial to the
compatibilist. And, finally, there is the point that we encountered in
our discussion of the new dispositionalism in Section 5.1, which is
that certain platitudes about ability -- in particular, those
involved in certain judgments about moral responsibility -- may
be recalcitrant to compatibilist treatments. Taken together, these
points seem to pose a serious obstacle to any theory of ability that
is both compatible with determinism and in accord with our ordinary
judgments about what ability requires.



What is the compatibilist to say in light of these obstacles? One
response is to make a distinction between two kinds of compatibilist
project. (Compare Pryor 2000 on responses to skepticism). One project
is to *convince* someone moved by the incompatibilist's
arguments to retreat from her position. Call this *ambitious*
compatibilism. For precisely the reasons van Inwagen gives, it is
doubtful that any theory of ability will suffice for a defense of
ambitious compatibilism. There is another project, however, that the
compatibilist might be engaging in. Let us say that, for some reason
or other, she herself is not convinced by the incompatibilist's
argument. She is still left with an explanatory burden, namely to
explain, if only to her *own* satisfaction, how it *could
be* that abilities are compatible with the truth of determinism.
Here the compatibilist's aim is not to convince the
incompatibilist of the error of her ways, but simply to work out a
satisfactory conception of compatibilism. Let us call this
*modest* compatibilism. This distinction is not often made, and
it is not always clear which of these projects classical
compatibilists are engaged in. If the latter project is indeed part of
classical compatibilism, then we may grant many of the above points
while still granting the theory of ability a central place in defenses
of compatibilism. For it may be that, though a theory of ability is of
no use to the ambitious compatibilist, it has a crucial role to play
in the defense of modest compatibilism.



Even these compatibilist aspirations, however, may be overly
optimistic, or at least premature. For in surveying theories of
ability we have turned up serious difficulties, for both hypothetical
and non-hypothetical approaches, which do not appear to turn on issues
about determinism. So it may be that the best hope for progress is to
pursue theories of ability while setting to one side the problems
raised in the free will debates. For given the difficulties posed by
abilities, and given the significance of theories of ability for areas
of philosophy quite removed from the free will debates, there is
something to be said for pursuing a theory of ability while embracing,
if only temporarily, a certain quietism about the puzzles that
determinism may pose.