Alex Byrne

Perceptual experiences justify beliefs—that much seems obvious. As Brewer puts it, “sense experiential states provide reasons for empirical beliefs” (this volume, xx). In Mind and World McDowell argues that we can get from this apparent platitude to the controversial claim that perceptual experiences have conceptual content: [W]e can coherently credit experiences with rational relations to judgement and belief, but only if we take it that spontaneity is already implicated in receptivity; that is, only if we take it that experiences have conceptual content. (1994, 162) Brewer agrees. Their view is sometimes called conceptualism; nonconceptualism is the rival position, that experiences have nonconceptual content. One initial obstacle is understanding what the issue is. What is conceptual content, and how is it different from nonconceptual content? Section 1 of this paper explains two versions of each of the rival positions: state (non)conceptualism and content (non)conceptualism; the latter pair is the locus of the relevant dispute. Two prominent arguments for content nonconceptualism—the richness argument and the continuity argument—both fail (section 2). McDowell’s and Brewer’s epistemological defenses of content conceptualism are also faulty (section 3). Section 4 gives a more simple-minded case for conceptualism; finally, some reasons are given for rejecting the claim—on one natural interpretation—that experiences justify beliefs

Our reply is in four parts. The first part addresses objections to our claim that there might be "unknowable" color facts. The second part discusses the use we make of opponent process theory. The third part examines the question of whether colors are causes. The fourth part takes up some issues concerning the content of visual experience. Our target article had three aims: (a) to explain clearly the structure of the debate about color realism; (b) to introduce an interdisciplinary audience to the way philosophers have thought about the issue; (c) to argue that colors are certain sorts of physical properties ("productances"). We are very grateful to the commentators in this continuing commentary for their criticism and constructive suggestions.

I know various contingent truths about my environment by perception. For example, by looking, I know that there is a computer before me; by hearing, I know that someone is talking in the corridor; by tasting, I know that the coffee has no sugar. I know these things because I have some built-in mechanisms specialized for detecting the state of my environment. One of these mechanisms, for instance, is presently transducing electromagnetic radiation (in a narrow band of wavelengths) coming from the computer and the desk on which it sits. How that mechanism works is a complicated story—to put it mildly—and of course much remains unknown. But we can at least produce more-or- less plausible sketches of how the mechanism can start from retinal irradiation, and go on to deliver knowledge of my surroundings. Moreover, in the sort of world we inhabit, specialized detection mechanisms that are causally affected by the things they detect have no serious competition—seeing the computer by seeing an idea of the computer in the divine mind, for example, is not a feasible alternative.