It's been ages since I've thought about fancy reliabilist views. Just a few questions for the aficionados out there.
Q1. Remember "Indexical Reliabilism"? From what I gather from Comesana's Phil Studies article published back in 2002, he thought he was developing a view he found in Sosa's work. Sosa drew that distinction between apt and adroit justification and Comesana found a way to talk about that distinction using some machinery developed by folks interested in two-dimensionalism. There might be some interesting differences between their approaches, but in terms of the epistemic aspects of their views, is there really much of a difference between Comesana and Sosa?
Q2. As for Home Worlds Reliabilism, the view once championed by Sarah Sawyer and Brad Majors, I don't see how adopting the view that justification is a matter of reliability in a subject's home worlds (i.e., sets of environments relative to which the natures of her intentional contents are individuated) is really going to help. If someone is caused to hallucinate by a demon from the cradle, as it were, it's true that they won't be a mental duplicate of ours. So, pointing to such an individual does not show that it's possible for someone to be in just our mental states and be without any reliable way of forming beliefs about the external world. But, as Comesana points out, HWR doesn't seem to have much to say about cases where a demon comes along on this weekend for your 32nd birthday (hint) and starts deceiving you. Your thought contents don't switch all that quickly and you seem pretty unreliable in the environment relative to which the natures of your thought contents are individuated.
Two further worries in this vicinity. Suppose we were convinced by philosophical arguments for error theory about color. So, suppose we were convinced that the ordinary folk are systematically wrong in their attributions of color. Okay, but aren't they justified in their non-inferential color judgments? I find this as intuitive as the original intuition underlying the new evil demon thought experiment.
Worse, think back now to our from-the-cradle-hallucinator. If this subject has beliefs (about God only knows what) and experiences with contents (representing God only knows what), we wouldn't say that this subject is reliable about whatever it is that the subject is thinking about (unless, perhaps, we think that this subject is thinking about demons), but if the transitions from experience to belief are rational as are the transitions from belief to believe, it seems we should say that this subject is justified in thinking about whatever it is thinking about. And, that seems to cause trouble for HWR because while our contents aren't individuated relative to such an environment, this subject's contents are so individuated.