PEA Soup

Ought and Can; Can't vs. Won't

G. A. Cohen has a diagnosis of what he thinks is going wrong with political philosophy, a diagnosis that is supposed to explain why, say, Rawls, Dworkin, and Nagel, or Nozick, Schmidtz, and Gaus, are relatively sanguine about markets, while Cohen thinks markets are inherently repugnant. The problem in his view is that philosophers illicitly allow facts about people are willing to do to act as a constraint on what they ought to do. But while it may be the case that you can't have a duty to X unless you can X, that doesn't mean that you can't have a duty to X just because you aren't willing to do X.

Does Ought Imply Can Outside Ethics?

[My apologies if this is well-trodden ground.  I am pretty ignorant of the ought-implies-can literature, and quick check over articles didn't reveal anybody discussing what I'm about to write.]

In general, philosophers take it for granted that a person morally ought to X if and only she can X.  I'll treat this as equivalent to claiming that a person can have an all-things-considered moral duty to X if and only she can X. So, e.g, I cannot have an all-things-considered duty to shoot magic fireballs from my fingers because I am physically unable to do so.

Outside of ethics, though, there seem to be a few cases where intuitively we don't accept this, or, at least, I don't.  

Paying People Not to Do Good: A Puzzle about Superogation

First, thanks to Doug and the other editors for the invitation!  I'm happy to be here.

For my first post, I wanted to share an issue that has been puzzling me.  Ultimately, this relates back to issues in voting ethics, but I want to submit the problem in the abstract.  I'm not sure what to say about it. I'm curious what others think (and if there's relevant published work on it.)

Suppose Alf plans to do X.  X is supererogatory--it's nice of him to do, but he isn't morally required to do it.  Betty doesn't want Alf to do X, so she offers to pay him not to do so, because she doesn't want him to do something supererogatory.  (Suppose also that it's legal for him to accept money not to X.)  My question: Is Betty doing something morally wrong?

Note: I'm not asking about what making the offer reveals about Betty's character.  That is, I'm not asking whether Betty's offering to pay Alf not to do something supererogatory shows that she has vicious character.  

Note also that there are cases where it's morally right to pay something to do Y, even though this foreseeably might prevent them from doing some supererogatory action X.  So, for instance, it's not wrong for our various universities to pay us our salaries, even though our working as philosophers prevents us from devoting our lives to charity work in the poverty-stricken regions.  [EDIT: Our employers are paying us to teach, not paying us not to do supererogatory volunteer work.]

Sometimes, Betty's actions seem wrong to me.  But other times, it seems like she's doing something permissible, though she has bad character.  After all, since X is supererogatory, it's morally permissible for Alf to refrain from X-ing, even for morally frivolous or vicious reasons.  (His reasons for refraining bear on his character, but generally not on the deontic status of the act.)  If so, why wouldn't it be morally permissible for Betty (for morally frivolous or vicious reasons) to pay Alf not to X?  [EDIT: Let's assume for the sake of argument that Alf is permitted to accept money not to X.]  

What do you think?