Puzzles of Color
The mantis shrimp challenges philosophical reflection. This little crustacean is reputed to have the most complex eyes in the animal kingdom. Mounted on stalks, these eyes can move independently and rotate freely; it has between 12 and 16 photoreceptors compared to the human 3. It can see into what is called deep ultra violet. It uses these eyes in the close capture of prey where great precision is needed (it also has a powerful club with which it stuns its prey). There is every reason to believe that this creature’s eyes are superior to human eyes; in particular, it has superior color vision. Presumably we don’t know what it’s like to be a mantis shrimp, since its color phenomenology outstrips ours (compare the bat’s perception of sound). Its visual phenomenology is like Technicolor compared to our dull monochrome. It sees more colors and it sees them better.
This raises puzzling questions. First, it suggests that colors exist independently of vision: just as some colors exist independently of human vision, so there may be colors that exist independently of all (terrestrial) vision. For there could be a species superior even to the mantis shrimp in the perception of color, so that color does not consist in actually causing color experiences. The wavelengths of light clearly pre-exist perceivers and it seems right to say that things were red (say) before any animal saw them as red. We can try saying that they had a disposition to appear red, but then there is no categorical property that being red consists in. For various reasons it is preferable to accept that things have colors before being perceived as such. The mantis shrimp thus has access to mind-independent colors that many other animals have no access to. But it is a puzzle what exactly these colors are: not wavelengths, and not dispositions to appear—but then what? They seem neither objective nor subjective but somewhere between the two; they challenge the usual binary opposition of objective and subjective. They seem to have phenomenology written into them and yet they are not identical to anything in the mind. They are, we might say, objective-cum-subjective. Perhaps they are a primitive type of property that belongs neither to the world of physics nor to the world of psychology. Yet they belong to physical objects and are perceived by the mind.
But that isn’t the puzzling question I most want to talk about. Suppose we say that colors are secondary qualities in the classical sense—dispositions or powers to elicit perceptual experiences. Then we must ask whoseperceptual experiences: is it our experiences or those of the mantis shrimp? Since its color vision is markedly superior to ours we can’t identify the two, which means that the same objects can elicit different perceptions of a given color: red looks one way to them and another to us. Are there then two reds? No, there are two appearances of the same red. But the shrimp sees red better than we do, so it can’t be that our experiences are determinative: better to say that the shrimp’s visual system gets to decide. But then couldn’t there be perception of red that outclasses even the mantis shrimp’s? The problem is that colors admit of more or less accurate perceptions of their nature, but that is not compatible with claiming that colors are such dispositions. No one’s visual system gets to decide what red is, because the appearance of red to different perceivers varies: being red must transcend how red looks to different visual systems. Suppose we try saying that the best visual system on earth determines the identity of the colors, say the mantis shrimp’s: then it follows that if this shrimp goes extinct we should turn to the second best perceiver of color on earth; but this move shifts the identity of red from one subjective appearance to another. There must be more to the color red than its subjective appearance to sundry perceivers of red. Maybe our visually acute shrimp gets the closest to the true nature of the color red, with us running a distant second, but neither of us gets to determine the intrinsic nature of the color red. But then the traditional secondary quality view of color has to be mistaken.  That would be fine if we could see our way clear to identifying colors with physical properties like wavelengths, but that way is blocked for familiar reasons.  The upshot is that colors again emerge as sui generis basic properties belonging neither to physics nor psychology; they occupy a curious no-man’s land of the objective-cum-subjective. Perhaps the mantis shrimp sees red exactly as it intrinsically is (that is certainly an appealing thought), but this judgment of exact correctness presupposes that something outside the shrimp’s visual system fixes the nature of the property—the shrimp gets it right according to an objective measure. We, on the other hand, see it through a glass darkly, or through a haze laughably. We certainly can’t claim that our visual impressions constitute the very nature of the color red. No one’s do. Colors are like shapes in having a nature of their own that is logically independent of how they appear to this or that perceiver, simply because different visual systems represent them differently. We might be said to be color blind not only with respect to colors we can’t see but with respect to colors we can, since our visual system might be, as it were, legally blind with respect to the real nature of color. But legally blind perceptions of color are hardly capable of constituting the essence of color. The quality we are seeing, then, is not identical to a disposition to elicit imperfect perceptions of color in us; there is such a disposition, to be sure, but it cannot be the color. Our perceptive shrimp has a better claim to fixing the true nature of the color, but even she is not capable of constituting color properties (save per accidens).
The same point can be made about other sensible qualities: smells, tastes, and sounds might not reveal themselves to our specific sensory systems.  Animals with superior senses to ours might experience these qualities quite differently from us, and in ways closer to their true nature. Yet none may quite get to the heart of the quality in question—perhaps no animal on earth has ever experienced what sugar really tastes like. So we cannot assimilate such qualities to dispositions to appear in certain ways to existing perceivers, since these appearances may be more or less inaccurate or imperfect. So again, the traditional secondary quality account cannot be correct. This leaves us with an implausible physical reductionism or an acceptance of a range of puzzling qualities that are neither one thing nor another. The world of sensible qualities lies tantalizingly out of reach, perceived only as veridically as the perceiver’s limited senses allow. Human sensation, in particular, might be feeble and misleading compared to other “humbler” creatures. To be sure, we have big penetrating brains, but our sense organs might well be rather superficial and misleading even with respect to qualities with which we fancy ourselves well acquainted. We might have a rather poor idea of what red is—not as poor as a blind man’s, certainly, but pretty dismal compared to the mantis shrimp’s. If we had a hundred color receptors instead of three, the world of colors might have a startlingly different phenomenology for us. We might then see colors as they really are.
 The traditional secondary quality theory of color was proposed at a time when human biological superiority was presupposed—it was assumed that the human perception of color must be authoritative. In our post-Darwinian age we are far more ready to accept that the human species might not set the standard for veridical perception.