I started with Neta's article and haven't finished it yet. I wanted to take a moment to comment on a passage from McDowell. In offering an epistemological rationale for disjunctivism, he writes:
The root idea is that one's epistemic standing on some question cannot intelligibly be constituted, even in part, by matters blankly external to how it is with one subjectively. For how could such matters be other than beyond one's ken? And how could matters beyond one's ken make any difference to one's epistemic standing? ... When someone has a fact made manifest to him, the obtaining of this fact contributes to his epistemic standing on the question. But the obtaining of the fact is precisely not blankly external to his subjectivity, as it would be if the truth about that were exhausted by the highest common factor
I take it that part of the idea here is that veridical perception is supposed to put us in a better epistemic position than a corresponding hallucination would. As Neta notes, the only explanation McDowell sees as to why this is would have to be something that made for a subjective difference.
Some will respond to McDowell's argument like this. There's no subjective difference between hallucination and experience of the sort that contribute to the subject's epistemic standing on the situation and so you aren't better off epistemically having a genuine experience rather than a hallucinatory one. Not, that is, if you're thinking about justification. If you're thinking about knowledge, that's a different matter.
I think there's a middle ground view here. Yes, you'll have better epistemic standing with experience than hallucination. No, that's not because there's a subjective difference. Or, more carefully, this difference in resultant status does not require a subjective difference. Thus, you can't argue from 'no subjective difference' to 'no difference in epistemic standing'. Here's why.
While reasons _for_ may well need to be present to the mind to improve one's epistemic standing, there's little reason to think that reasons _against_ need to be present to the mind to affect epistemic standing negatively. A reason to or for cannot justify unless it figures in deliberation to guide the subject's deliberations but a reason against need not figure in deliberation or guide deliberation to get its normative work done. (Reasons against get their work done by making wrong whereas reasons for get their work done by justifying.) If that's right, we could say that the advantage you get with experience is the absence of a reason against that you get whenever you hallucinate. Since reasons against needn't be present to the mind to get their work done, we can explain the resultant difference that McDowell is after without having to go all McDowellian and posit some subjective difference most of us don't believe in.