Updated version. It's much clearer.
When is it permissible to treat something as a reason for action? According to Hawthorne and Stanley (forthcoming):
(KRP) When S’s choice is p-dependent, it is permissible for S to treat the proposition that p as a reason for acting if and only if S knows that p.
According Neta (forthcoming), we ought to reject KRP in favor of the weaker principle JBKRP:
(JBKRP) When S’s choice is p-dependent, it is permissible for S to treat the proposition that p as a reason for acting if and only if S justifiably believes that she knows that p.
It’s tempting to dismiss KRP on the grounds that it delivers the wrong verdicts in some Gettier cases. Here is Neta’s version of the objection. Suppose that you justifiably believe that your partner loves you and suppose further that you justifiably believe that you know that this is the case. Suppose further that aliens have replaced most of the humans in your area with indistinguishable, emotionless doppelgangers. Let’s suppose that you know that if you’re unloved, you are better off buying beer. You know also that if you are loved, you are better off buying your partner flowers. Thus, the choice whether to use the money in your pocket to buy beer or buy flowers depends on whether your partner loves you. It seems that it’s not wrong for you to choose the flowers over the beer acting on the belief that your partner loves you even if you don’t know that your partner loves you if the only reason you don’t know is that you live in love façade country. (If Hawthorne and Stanley say that it’s an excusable wrong, that still seems wrong as it seems there is nothing to excuse.)
There’s a sense in which it seems that something along the lines of JBKRP must be true. It seems that justification is a deontological notion in the sense that you should never believe without justification and it is always permissible to believe a belief if its justified. If you accept this while rejecting a justification account along the lines of JBKRP, you are committed to saying that situations can arise in which it is permissible to believe that p is the case but impermissible to include the belief that p is the case in deliberation even if you know that deliberation is concerned with some p-dependent choice. I shall argue that if justification accounts do border on the trivial, we are badly mistaken about what is involved in the justification of belief and Neta’s counterexample to KRP is a counterexample to JBKRP. If, however, we work with an orthodox account of justification, there is a wide range of cases that constitute counterexamples to JBKRP that don’t threaten KRP.
Suppose you face a choice between two options, staying and going. If you go there will be trouble, but if you stay there will be double. So, suppose that you ought to go rather than stay. Let p be the proposition that you ought (all things considered) to stay. Because p is false, you cannot know that p is the case. Because you do not know that p is the case, according to KRP you should not treat p as a reason for action. Suppose it is possible to justifiably believe that you know p even if you do not know that p. Then, according to JBKRP, it is permissible to treat p as a reason for action in, say, adopting means you know to be sufficient for bringing it about that you stay. But that’s absurd. How could it be permissible to treat the proposition _that you ought (atc) to stay_ as a reason for acting when it’s impermissible to stay?
It would be ad hoc to say that beliefs about what should be done cannot be both justified and false if the falsity of a belief is not generally regarded as a condition necessary for justifiably believing a contingent proposition about the external world. Not everyone thinks, however, that there can be false, justified beliefs. Sutton (2007), for example, has argued that we ought to identify justified beliefs with items of knowledge. So, if we were to say that the right to treat some proposition or fact as a reason for action is secured once you justifiably believe that the proposition or fact is the case and combine this with the knowledge account of justified belief, the resultant account is immune to objection just raised. However, if any Gettier case constitutes a counterexample to KRP, the same case constitutes a counterexample to JBKRP if we strengthen that account by insisting that there cannot be false, justified beliefs.
If you think, as I do, that it’s inconceivable that something along the lines of JBKRP could turn out to be false, it seems that you just might have to say that justification is factive. If justification isn’t factive, but some justification account of when it is permissible to treat something as a reason is correct, it should be possible for circumstances to arise in which it is permissible to believe p but not to include that belief in deliberation even though you know that the choice you face is p-dependent. The only alternative is to say that circumstances can arise in which it is permissible to deliberate from the belief that you ought to Φ even though it is impermissible to Φ. That possibility is difficult to make sense of. It suggests that the reasons that bear on whether to Φ are somehow different from the reasons that bear on whether to judge that you should Φ. If normative reasons demanded that we somehow act against our own judgment about what to do while keeping that judgment in place, it seems only the deeply irrational could manage to do everything that the reasons required. Reasons cannot be that unreasonable.