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Instead of focusing, in the style of the “neural correlates of consciousness” (NCC) approach, on a single exemplary conscious experience—like the experience of “seeing the color red”—Tononi and Edelman asked what was characteristic about conscious experiences in general. They made a simple but profound observation: that conscious experiences—all conscious experiences—are both informative and integrated. From this starting point, they made claims about the neural basis of every conscious experience, not just of specific experiences of seeing red, or feeling jealous, or suffering a toothache. The idea of consciousness as simultaneously informative and integrated needs a little unpacking. Let’s start with information. What does it mean to say that conscious experiences are “informative”? Edelman and Tononi did not mean this in the sense that reading a newspaper can be informative, but in a sense that, though it might at first seem trivial, conceals a great deal of richness. Conscious experiences are informative because every conscious experience is different from every other conscious experience that you have ever had, ever will have, or ever could have. Looking past the desk in front of me through the window beyond, I have never before experienced precisely this configuration of coffee cups, computer monitors, and clouds—an experience that is even more distinctive when combined with all the other perceptions, emotions, and thoughts that are simultaneously present in the background of my inner universe. At any one time, we have precisely one conscious experience out of vastly many possible conscious experiences. Every conscious experience therefore delivers a massive reduction of uncertainty, since this experience is being had, and not that experience, or that experience, and so on. And reduction of uncertainty is—mathematically—what is meant by “information.” The informativeness of a particular conscious experience is not a function of how rich or detailed it is, or of how enlightening it is to the person having that experience. Listening to Nina Simone while eating strawberries on a roller coaster rules out just as many alternative experiences as does sitting with eyes closed in a silent room, experiencing close to nothing. Each experience reduces uncertainty with respect to the range of possible experiences by the same amount. In this view, the “what-it-is-like-ness” of any specific conscious experience is defined not so much by what it is, but by all the unrealized but possible things that it is not. An experience of pure redness is the way that it is, not because of any intrinsic property of “redness,” but because red is not blue, green, or any other color, or any smell, or a thought or a feeling of regret or indeed any other form of mental content whatsoever. Redness is redness because of all the things it isn’t, and the same goes for all other conscious experiences.
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