Siegel and Byrne debate whether perceptual experiences present rich properties or exclusively thin properties.

Is perception cognitively penetrable, and what are the epistemological consequences if it is? I address the latter of these two questions, partly by reference to recent work by Athanassios Raftopoulos and Susanna Seigel. Against the usual, circularity, readings of cognitive penetrability, I argue that cognitive penetration can be epistemically virtuous, when---and only when---it increases the reliability of perception.

The phenomenon of cognitive penetration has received a lot of attention in recent epistemology, as it seems to make perceptual justification too easy to come by for experientialist theories of justification. Some have tried to respond to this challenge by arguing that cognitive penetration downgrades the epistemic status of perceptual experience, thereby diminishing its justificatory power. I discuss two examples of this strategy, and argue that they fail on several grounds. Most importantly, they fail to realize that cognitive penetration is (...) just an instance of a larger problem for experientialist theories of perceptual justification. The challenge does not lie in explaining how cognitive penetration is able to downgrade the epistemic status of perceptual experience, the challenge lies in explaining why perceptual experience would have a special epistemic status to begin with. To answer this challenge, experientialists have to solve the distinctiveness problem: they have to explain what is so distinctive about perceptual experience that enables it to provide evidential justification without being in need of justification itself. Unfortunately, an internalist answer to this problem does not appear to be forthcoming, even though it would certainly help with explaining the problem of cognitive penetration. (shrink)