Cognitive Penetrability and Perceptual Justification*

Abstract

It is sometimes said that in depression, everything looks grey.1 If this is true, then mood can influence the character of perceptual experience: depending only on whether a viewer is depressed or not, how a scene looks to that viewer can differ even if all other conditions stay the same. This would be an example of cognitive penetration of visual experience by another mental state. Here the influential cognitive state is a mood. Other putative examples of cognitive penetrability involve beliefs: to the reader of Russian, the sheet of Cyrillic script looks different than it looked to her before she could read it. When you know that bananas are yellow, this knowledge affects what color you see bananas to be (an achromatic banana will appear yellowish).2 Or suppose that to a vain performer, the faces in the audience ranged in their expression from neutral to pleased, but remarkably no one ever looked disapproving, while to an underconfident performer, the faces in the audience ranged in their expression from neutral to displeased, but remarkably no one ever looked approving. Potential cognitive penetrators thus include moods, beliefs, hypotheses, knowledge, desires, and traits. In some cases, cognitive penetration can be epistemically beneficial. If an x-ray looks different to a radiologist from the way it looks to someone lacking radiological expertise, then the radiologist gets more information about the world from her experience (such as whether there’s a tumor) than the non-expert does from looking at the same x-ray. If Iris Murdoch and John McDowell are correct in thinking that having the right sort of character lets you see more moral facts than someone lacking that character sees when faced with the same situation, then there too, your perceptual experience becomes epistemically better, thanks to its being penetrated by your character.3 In other cases, however, cognitive penetration seems to make experience epistemically worse. The challenge to perceptual justification posed by