Shufflebrain

Color manipulations also let us mimic human mental activities. For example, suppose we construct a hologram with green light. During reconstruction, suppose we use light with wavelengths longer than green-- red, for instance. The rule for "remembering" the scene, recall, is to use a wavelength equal to or shorter than the original. Thus the red light cannot regenerate the scene. But the hologram still has a memory of the scene, doesn't it? We simply can't decode it with red. As is the case with construction angles in the multiple hologram, displaying the information means satisfying certain conditions-- wavelengths, in the case of color.

Kilpatrick's scanning model might employ wavelength as well as angle of tilt to simulate the act of recalling a memory. (Indeed, the use of both would make a more versatile model.) Suppose we use a blue reconstruction beam, which has a shorter wavelength than green. Then we would produce a scene from a hologram that had been constructed with green light, although the color of the reconstructed scene would be blue instead of green. Suppose we don't know the original color. If we began scanning from the red end, we would pass through a considerable portion of the visible spectrum before any scene at all appeared. But once into and beyond the green zone, we would reconstruct the scene through a vast range of greens, blues, and violets and never know just what wavelengths had been used during construction.

Think of our own recollection process. How often have you scanned your memory to recall a past experience and, having recalled it, seen it in your mind's eye with different details from those of the experience itself? We almost never remember things perfectly. What would happen if we used red-green-blue in our model? We could vary the reconstruction wavelengths over a vast range indeed. We might contrive a wavelength mixture where, suddenly, everything seems to go blank (if we hit the counterparts of subtractive primary wavelengths). These properties give the hologram many features that Freud and his followers envisaged for the human mind.

Can we actually simulate the subconscious mind with holograms? A model is implicit in what I have already described. To illustrate it further, let's return to our green hologram. Suppose that during scanning we move off into ultraviolet wavelengths, beyond the visible region of the spectrum. There the wavelengths are shorter than green, and thus fully able to regenerate an image. But beyond the visible spectrum, the image would be invisible; and we would have to use special film or meters in order to detect it. Invisible or not, the image would burn itself into our retinas if we were foolish enough to look in its direction long enough, for the same reasons that we can suffer severe sunburns on cloudy days. Likewise, our physiology can come under incredible stress from thoughts, feelings, and so forth that do not surface in the conscious mind.

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Acoustical holographers also do very interesting things with color. In an excellent Scientific American article in 1969, Alexander Metherell (the same person who showed that holograms are about phase) reported his methods for making full-color holograms. He used sonic waves of three different frequencies, but frequencies whose ratios corresponded with red-green-blue . He then used mixtures of light to reconstruct multicolored scenes. Sound is not light, of course. Nor are sonic frequencies colors. Metherell's experiments dramatize the truly abstract nature of the hologram's code. He encoded color information not with wavelengths but with ratios of wavelengths.

Metherell's experiments suggest many features of mind we have already discussed. In addition, they hint at a physical model of language.

Modern theoretical linguists believe that languages do not evolve pell-mell from the raw sound-producing capabilities of our voice boxes, tongues, cheeks, teeth, and so on. All languages, they believe, follow certain general rules of syntax. Still, no matter how convincing the linguists' arguments are, German is not Korean. In Metherell's experiments, ratio was the rule. But to reconstruct a specific color, Metherell did have to pay attention to specific wavelengths. Wavelength ratio can serve as an analog of the general rules of syntax, and specific wavelengths can be models of the particular features of a specific language.