Apart from whatever sense in which the world is real, realness is also a quality projected upon it by the mind, a judgment concerning the status of experience.

     We may observe how structure in the input is preserved in various stages of information processing. If structure is considered the bare bones of reality, we may wonder how the mind fleshes out this skeletal structure with the qualities characteristic of the "show" of experience. If we consider structure or information to be, so to speak, the raw material of the factory of mind, how does it become the finished product we experience?

     But there is something fishy about this question, for 'information' and 'structure', far from being raw materials, are highly refined constructs in the cognitive domain of science. Structure is no more what remains, when the perceptual world is stripped of its qualities, than the outlines in a coloring book are what remain when the colors are removed from a photograph. An outline must be deliberately drawn in, structure must be intentionally imposed.

     Information or structure certainly can be considered the starting domain, the raw material of mind-- but only arbitrarily and conventionally. This is equally true of perception or sensation, which are sometimes treated as analog domains from which cognitive judgments are extracted. The problem is that one never experiences such a thing as a pure perception or sensation free from cognitive judgment. In other words, there is no such thing as a sense datum. Rather, a perception or sensation is a cognitive judgment. A pure musical tone, or a pure color not associated with a physical surface, is not an informationally superfluous filling in of some structured domain of sound waves or light waves (--an epiphenomenon!). Rather, these sensations are informationally rich judgments concerning the structure of those domains. Specifically, they are estimations of frequency. This is straightforwardly true in the case of sound: the experience of tone emerges as the wave fronts impinge too rapidly to be distinguished individually. But what is the sound of one wave lapping? It is certainly not a tone, which is the global effect of a collection of wave fronts.

     The case of color is more complex. Apparently, color is distinguished on the basis of the relative intensities of low and high frequencies, for which there are separate sets of receptors. Color vision does not operate, as once thought, through direct sensitivity to frequency. (The fascinating experiments of Land-- of Polaroid fame-- are instructive). Though frequency is not precisely the structure mapped by color experience, the latter nevertheless maps a set of relations in the world that is relevant to the organism. Both the experience of color and of auditory tone can be regarded as isomorphisms of structures in the world, alternatively described in domains created by reductive science. They are the experience, in the ordinary human cognitive domain, of those structures .

     In the case of sound, at least, the tone heard and the frequency measured by instrument are two equivalent expressions of the same cognitive judgment. (In the case of color, the relation may be slightly more complex). In both instances, in addition to this cognitive judgment, structure in the sensory apparatus itself may be projected into sensory experience-- since it can only be experienced as structure in the world. A clear example of this is the organization of the perception of sound into octaves. Vibrations of frequencies x, 2x, 3x, etc., are perceived as qualitatively the same note in different octaves. There is, of course, no such qualitative structure in the continuum of sound frequencies. The mind is responding rather to a quantitative structure through its experience of quality. The human eye perceives but one octave of the electromagnetic spectrum, which it divides into a quasi-discontinuity of colors. Yet it is apparent that if the eye were sensitive to a wider range of frequencies, perceived colors would repeat in a way similar to perceived octaves of sound, for the farthest ends of the humanly visible spectrum (violet and red) begin to resemble each other qualitatively . In both examples this is due to the similar reaction, by the receiving sense organs, to wavelengths that are multiples of each other. An oscilloscope also displays the same information: that a frequency and its multiples are congruent.

     The apparently mysterious, projective, filling-in faculty of mind is ubiquitous so virtually transparent. Only in perceptual anomalies do we notice it at all. These include completion effects, habituation, adaptations of various sorts, and other phenomena of projection. Some examples are given in the Appendix. But the question suggested by these phenomena, of how the experience of tone or colour arises from an analysis of frequencies (or some other construct in the domain of scientific description), engages us in a subtle misunderstanding, because the experience of sound or color is the subject's experience of analysed frequencies. The question suggests a homunculus in there (or a brain or computer) computing answers to problems formulated in the very cognitive domain one is trying to explain. Beginning with a demon in the machinery, we end up with the ghost in the machine. For no matter how good causal descriptions get at explaining the performance of perceptual systems, they never seem to demystify the miracle of experience. The experience of the little man, doing his calculations, is of symbols and quantities, dials and levers-- all in the domain of his sealed control room-- not of qualities such as color and tone in the world outside. Tones, colors, smells and other qualities may indeed be understood as completion effects. But they appear as superfluously filled in, within and distinct from some skeletal structure of information, simply because such structure was abstracted from phenomenal qualities in the first place. (This is the subject-object split on an intimate scale). The quality, for instance of greenness, is "filled in" between wave fronts of light in just the way that the quality of being fifty years old is filled in between one's fiftieth and fifty-first birthdays: that is, by intention. The irreducibly self-luminous quality of qualia is not a property of the world but an act of the intending mind. The mystery of how structure, mapped in neurophysiological processes, can result in experiences of color, tone, pain, or other qualities, is no more (or less!) mysterious than the process by which sound waves can carry meaning as words, or algebraic symbols come to be imbued with numerical significance.

     Nerve impulses, sense data, or other constructs in the domain of science, can be taken as the initial conditions for the cognitive processes in question-- but only by convention. By analogy, in an "interpreted" formal system such as the set of integers, we do not begin with a bunch of meaningless squiggles and then find referents for them, but rather we begin with the intuited meanings of numbers. Abstraction and generalization come as afterthoughts in the history of mathematics. The abstractions of numbers are then conceptually recycled as though they came first historically, since logically they do in the cognitive domain of abstract algebra. In the cognitive domain of psychology, there must similarly be some starting point in the chain of explanation, and so psychologists and philosophers have invented a variety of them. So be it. But either the starting point is the world-in-itself and not "the physical" (which is already a mental construct)-- and hence there is no question of the mental arising from the physical. Or there are specifiable conventions ("the physical") from which the qualities of experience unaccountably arise. Since science has chosen the latter course, we may have to live tolerantly with dualism, but we do not have to be hoodwinked by it.

     Intentional states are physical connections within an organism which are also logical connections within the mind of the organism as an informal system. The flow chart of behavior can be described logically or causally. In this sense, the mental is the physical, for they are two analyses of the same behavioural system. This identity still leaves out the fact of conscious experience, for they are both third-person descriptions. How do we get, finally, from third to first person? How does the object become subject? How does a system have experience, have a point of view? What is the solution to the Mind-Body Problem?

     We can recognize here the stalemate I have called the Problem of Cognitive Domains. For, ideas of 'logical connection' and 'intentional system' are abstracted from extensional experience, while we want to know how experience of the extensional world arises from "mere" logical connection within an intentional system. If we are not willing to accept as an answer that it arises by intention-- in the way that words come to have meaning-- then we are besotted still with the ineluctable fact of being conscious subjects in the first person. If intentionality is not acceptable as a solution, then I propose that we are forced to simply accept that there is indeed "something that it is like to be" an intentional system, just as we are forced to simply accept that there is a cosmos rather than nothing. The two great mysteries remain untouchable because we cannot get upstream from either existence or consciousness. Matter is, and our conscious experience is the point of view of the material systems inquiring about it.