5. My Response to the DIA, First Approximation
My general strategy against the DIA involves calling into question the Experience Assumption. Recall that according the Experience Assumption is formulated as follows:
Shade blue1 gives rise to a conscious experience with a phenomenal character at time t1 that is distinct from the phenomenal character of the conscious experience that the shade blue2 gives rise to at time t2.
The gist of my strategy will center on the suggestion that, contrary to the Experience Assumption, one does not have, at time t1, an experience with a phenomenal character that is distinct from the phenomenal character one has at time t2. As I say, that’s the gist. Spelling this out with more precision will take some time and care. I develop my line of response to the DIA as a pair of approximations, the second approximation dealing with objections that arise for the first approximation.
Recall that in an earlier section I said that there are two general explanatory strategies for accounting for a failure to diachronically discriminate colors that are synchronically discriminable: one may explain the failure as either a kind of memory failure and the other as a kind of perceptual failure. The specific response that I will be developing is in terms of a kind of perceptual failure. More needs to be said, of course, about what it is that, despite the failure, is perceived. Of course, one kind of perceptual failure would be a failure, at time t1 or t2 (or both), to perceive anything, but clearly it is implausible to attribute a temporary total blindness to the subjects presented with these stimuli.
More plausible than attributing a temporary total blindness would be to attribute to the subjects visual experiences with the same phenomenal characters at time t1 and t2. Such an explanation would account for a failure to discriminate blue1 from blue2 by hypothesizing that the way blue1 seemed at t1 was the same as the way blue2 seemed at t2. In keeping with the gist of conceptualism, the conceptual content that either exhausts or matches this single phenomenal character would be the same conceptual content at t1 and t2. Suppose, for the sake of illustration, that the concept deployed on both occasions is the concept LIGHT BLUE. The suggestion under examination, what I’ll call the First Approximation, is that the Experience Assumption is false because what contents of the conscious experiences at t1 and t2 are the same: what’s consciously perceived regarding the color of the respective stimuli is that each is light blue.