General ability as generic ability?
Ability modals have a "specific" and a "general" reading. If a pianist is locked in a piano-free cell, they can play the piano in the general sense, but not in the specific sense. Roughly, an agent has the "general ability" to φ if they have the internal constitution required to φ. They have the "specific ability" to φ if, in addition, the external circumstances make it possible for them to φ.
What is the connection between the two notions? Some, e.g. Mandelkern, Schultheis, and Boylan (2017), hold that 'S can φ' expresses specific ability, and that the general reading results from the application of a tacit genericity operator 'Gen'. This is a natural idea, given that general abilities are often called 'general'. (Mandelkern, Schultheis, and Boylan (2017) even call them 'generic'!) The proposal is also tempting for accounts of ability that only directly capture the specific reading. (The locked-in pianist, for example, clearly wouldn't succeed to play the piano if they tried.)
But the proposal looks improbable to me. How would the 'Gen' operator manage to distinguish between internal and external prerequisites?
Let's make the supposedly specific reading of 'S can φ' explicit and replace it with 'S's internal state and external circumstances allow S to Φ'. If we apply a genericity operator to this, we don't get an expression of general ability. A pianist has the general ability to play the piano even if it is not true generically (normally, as a rule, or whatever exactly this means) that the circumstances provide a functioning piano.
Mandelkern, Schultheis, and Boylan (2017) briefly mention this problem. They reply that the "normal" situations over which 'Gen' quantifies are situations in which the external prerequisites are satisfied. This, they say, is independently supported by generics like 'George makes great ratatouille'.
But 'George makes great ratatouille' doesn't mean that George normally makes great ratatouille in situations where he has all the ingredients, a stove, a pot, etc. (These conditions may well be satisfied most evenings when George cooks dinner, and yet he rarely makes ratatouille.) It rather means, roughly, that cases in which George makes ratatouille are normally cases in which he makes great ratatouille. We can see the same effect with 'always': 'George always makes great ratatouille' has a natural reading on which it only quantifies over occasions where George makes ratatouille. How come? Because adverbs of quantification generally seem to be restricted to cases that result from the prejacent by replacing focussed constituents (here, 'great'). This is the explanation given in Beaver and Clark (2008), for example, where the effect is called 'free association with focus'.
I don't see any independent reason to think that 'Gen' can somehow select cases in which external preconditions for the prejacent are satisfied, while holding fixed the internal preconditions. (I know this is talk of 'internal' and 'external' is rough and doesn't quite fit the phenomena, but I don't think the imprecision matters.)
Also, compare 'able' with 'feasible'. On its most natural reading, 'it is feasible for S to φ' expresses (more or less) that S has the specific ability to φ. If applying a tacit 'Gen' to 'S is able to φ' results in a general ability statement, we should expect the same to happen for 'it is feasible for S to φ'. But I'm not sure if feasibility statements have a "general" reading that abstracts away from the contribution of the circumstances. Is it feasible for me to play the piano, if I'm locked in a piano-free cell? I'd say it is not.
We need a different account of how 'S can φ' gets to have a specific and a general reading.