Here is a tempting idea about representational precision. Representational precision is just a matter of how much the stimulus can change without changing the representational content of the subsequent perception. And the same idea extends to phenomenal precision: phenomenal precision is a matter of how much the stimulus can change without changing the phenomenal character of the perceptual state. Of course these ideas would not be useful if one included stimulus changes that don’t make a difference when the subjects’ eyes are closed or in the dark or in a dust storm. So the proposal does not get even to first base without specifying that the circumstances of perception must be ideal.
Here is an example: Suppose one is looking at an oriented line. If a change of up to but not beyond plus or minus 1 degree makes no difference in the percept of the orientation in ideal conditions, then the representational precision is plus or minus 1 degree. And the same thought also covers phenomenal precision. If a change of up to but not beyond plus or minus 1 degree makes no difference in the phenomenology of the percept of the orientation in ideal conditions, then the phenomenal precision is plus or minus 1 degree. One advantage of this conception of precision is that representational and phenomenal precisions will be comparable. And representationist ideas can be tested. If phenomenal precisions are smaller, i.e., more precise than representational precisions, then representationism is definitely over.
I like this idea of precision for cases in which it is fairly clear what ideal conditions would consist in. But if one is concerned that phenomenal precision is not a coherent notion, this suggestion will not be of much help. The problem with this suggestion is that the notion of ideal conditions will inevitably smuggle in the ideas that are supposedly being explained. In the case of representational content, the problem has often been called the “problem of error” (Fodor 1987): representational states correlate best—not with their truth conditions—but with conditions that include systematic error. A notion of ideal conditions that avoided this consequence would itself have to distinguish between veridical and falsidical representations (see Adams & Aizawa 2010).
Fink’s proposal about phenomenal precision sometimes sounds like the correlational idea just mentioned—that phenomenal precision is a matter of how much the stimulus can change without changing the phenomenal character of the subsequent perception in ideal circumstances. However, Fink goes on to explicate the notion of change in the phenomenology of the percept in terms of discernability: “for example, the pain caused by 480mc/sec/cm2 is not reliably discernible from one caused by 640 mc/sec/cm2.” And he goes on to spell this out in terms of the lower bound on p-precision being the range of cases “one cannot distinguish by experiencing as F under ideal conditions.” (p. 8). In the conclusion of the paper, Fink describes his proposal in terms of the notion of a “just noticeable difference [JND] as a lower bound of p-precision.” (p. 12)
However, what one can distinguish from what is a matter not just of phenomenology but of an interaction between phenomenology and cognition. As I noted (Block 2015, sections 6 & 10), discriminability is neither necessary nor sufficient for phenomenal difference. It is not sufficient because there are sometimes ways of discriminating between percepts that do not depend on a phenomenological difference, such as beats on vibrating strings. And it is not necessary because not all phenomenological differences need be accessible to the cognitive apparatus of the subject. I mentioned phenomenal Sorites cases (Morrison 2015) in connection with this point. As has often been noted, colors A and B may be indistinguishable because the difference between color A and color B is below the JND. And B may be indistinguishable from C for the same reason even though A is distinguishable from C. One way of thinking about this is that A and B may actually look different—i.e., produce percepts with different phenomenologies, but the difference in phenomenologies may be cognitively inaccessible. If so, noticeable differences will not track phenomenal differences.[9]
In short: phenomenal precision can be explicated in terms of the extent to which the stimulus can change in ideal conditions without changing the phenomenology of the resulting percept; but explaining changes in the phenomenology of the percept in terms of noticing or in terms of discrimination brings in an interaction with cognition that ruins the explication.
I welcome Fink’s suggestions about how to explicate phenomenal precision so long as the notions of discrimination and noticing are stripped from the explication and it is acknowledged that we have no reductive account of ideal conditions. And I acknowledge the possibility of solely generic phenomenology but I don’t think it creates the problem Fink mentions for my overflow arguments.