Veridical Hallucination and a New Evil Demon

Consider the course of sensory experience to which I have been subject throughout my life. Being a natural empiricist, I have come to believe much of what I believe on the basis of this experience. Presumably, this experience has given me warrant for many of the beliefs I have formed on its basis, such that these beliefs rise to the happy status of knowledge. However, there are possible situations in which I am subject to a phenomenally identical course of experience which fails to produce knowledge. (pace the disjunctivist)

Descartes' evil demon scenario, one presumes, describes such a possibility. In his scenario, my knowledge is defeated because the beliefs I form on the basis of experience are false. It is something of an open question whether the existence of such knowledge-defeating possibilities entails that my beliefs in actuality fail to rise to the status of knowledge. Call this the Vexed Question. In asking the Vexed Question about the Cartesian scenario we ask "does the existence of a possibility in which my beliefs are defeated by being made false defeat my actual beliefs?"

However, truth is but one requirement on knowledge. And one might wonder whether there are possibilities in which my beliefs are defeated, but not in virtue of being false.

Consider, then, veridical hallucination. To be subject to veridical hallucination is to be subject to visual experience that is accurate (i.e. veridical), but part of an episode of hallucination. Imagine, for a (sort of) example, dreaming, that the house is flooding, when (in reality) it is.

If veridical hallucination is possible, and if the fact that one is hallucinating rather than perceiving defeats knowledge, then there exists a skeptical scenario. In this scenario, my course of experience is as veridical as it is in the actual world, but is nonetheless wholly hallucinatory. In this scenario, I form the same beliefs on the basis of experience as I do in the actual case. And, interestingly, almost all of these beliefs are true. However, because the course of experience is hallucinatory, rather than perceptual, despite their truth, these beliefs cannot constitute knowledge on my part.

In asking the Vexed Question of my evil demon we ask "does the existence of a possibility in which my beliefs are defeated by being gruonded in hallucinatory (though veridical) experience defeat my actual beliefs?" Does answering the Vexed Question work differently in these two kinds of cases -- the truth defeating demon and the perception defeator demon?

Has anyone written about this, I wonder.