Does Experience Have Phenomenal Properties?

What assumptions are built into the claim that experience has “phenomenal properties,” and could these assumptions turn out to be false? I consider the issue specifically for the similarity relations between experiences: for example, experiences of different shades of red are more similar to each other than an experience of red and an experience of green. It is commonly thought that we have a special kind of epistemic access to experience that is more secure than our access to the external environment. In the first part of the paper, I argue than one way of elucidating this claim is especially plausible—that systematic error, of the kind subjects make about the external environment in traditional “skeptical” scenarios, is not conceivable for introspection of experience, including for our knowledge of similarity relations. I argue that focusing on similarity relations gives us a more interesting version of the argument than for other forms of experiential introspection. Then in the second part of the paper I describe an example, inspired by a similar case due to Sydney Shoemaker, in which a subject, despite being fully rational and attentive, apparently is systematically mistaken about the character of their experience in a surprising way. I argue that the example calls into question whether there are properties of experience satisfying the epistemic access constraint, and therefore whether experience has “phenomenal properties” in the intuitive sense.