“One has knowledge of one’s own percepts.” Percepts are often given epistemic privileges, meaning that they need no justification to be known, but I see no justification for giving them epistemic privileges. It seems like the dark side of epistemology to me.

Why? I realize that Yudkowsky isn't the most coherent writer in the universe, but how the heck did you get from here to there?

A simple qualia-based argument against skepticism (i.e. percepts are simply there and can't be argued with) is problematic- even if you conceded direct knowledge of percepts, you couldn't really know that you had such knowledge. They do not deal with rationality and there aren't any premises you could create from them. It seems less of a foundational tree of justification than a collection of meaningless smells, sounds and colors.

This doesn't mean that there are no qualia-based arguments that are worth looking at; in fact I think it is the most fruitful path to epistemic justification. I'm just trying to explain (what I think is) your objection more properly.