I'm enjoying the sun and reading John Gardner's Offences and Defences. Excellent, excellent read. Right now, I'm focusing on his discussion of the relationship between reasons and justification. On his view, justification depends on both guiding and explanatory reasons:
No action or belief is justified unless it is true both that there was an applicable (guiding) reason for so acting or so believing and that this corresponded with the (explanatory) reason why the action was performed or the belief held. It follows that the common view that there are two different perspectives on justification, a 'subjective' (explanatory reason) perspective and an 'objective' (guiding reason), must be rejected (94).
I think he's right that we ought to reject talk of subjective and objective justification. It's a shallow way of trying not to deal with a real issue. That being said, it seems to me that you could say that justification depends on both guiding and explanatory reasons without adopting the further view that there is 'correspondence' between the explanatory and guiding reasons. Instead of saying that the justification of action depends both on conforming to the relevant guiding reasons' demands and acting from an undefeated reason (Gardner's view, if I understand him), we could say that the justification of the action depends negatively on the sort of explanatory reasons that led the agent to act or believe. While acting from the wrong sort of reason could make an otherwise justifiable action unjustified, the justification of the action does not depend on both conforming to the relevant guiding reasons and being moved by considerations that 'correspond' to an undefeated reason.
Why does Gardner prefer the view that one must act for an undefeated reason to perform a justified action to the view that there must be an available justification for that action? He says that while, "guiding reasons for an against action are there to guide actions, not to guide explanatory reasons for action", it does not follow that "guiding reasons wash their hands of the quality of our reasoning, so long as we do the right thing in the end" (100). They do not because, "it is a basic principle of practical rationality ... that one should always act for some undefeated reason, i.e., that at least one of the (guiding) reasons in favor of doing as one did should have been one's (explanatory) reason for doing it" (100).
The justification Gardner offers for this principle is instrumental. He writes, "principles of rationality exist purely to guide us towards conformity with moral reasons, legal reasons, and so on, whatever those reasons may happen to be" (100). What's puzzling about this is that on the occasion where we do the right thing in the end, so to speak, there's nothing left to do to conform to the demands of the relevant reasons. Now, I don't think that Gardner denies this. Things become more puzzling if we note, as he does earlier in the chapter, that in the strict sense a justification is called for when someone has reason not to act or believe as one does (95). It seems that there's nothing objectionable per se about someone's conforming to a guiding reason acting on either a defeated reason or a reason that could not defeat one of the reasons against the action. There is something objectionable about someone's acting from bad motives or with evil intentions, but you can avoid doing that without acting from (explanatory) reasons that correspond to an undefeated guiding reason. When you know that this is what you're doing, I can't see what work is left for the principle of practical rationality.