|
|
|
|
|
|
What does it mean that humans are conscious, in the everyday sort of sense, and can science explain how and why it happens? Why are we conscious in the subjective way we are, when other creatures get along perfectly well without this particular capacity? In order to approach this question, Humphrey believes we must first describe the processes of consciousness in such a way that a Martian scientist would not only understand them abstractly, but factually (and empathically too, if that were possible). Seeing Red tackles this task with a directness and dignity seemingly not often achieved in current technical writing. Based on a set of lectures given at Harvard University in 2004, the book is completely engaging and comfortably authoritative. Humphrey draws on decades of study and reflection on mind, self, and consciousness. Readers of his earlier works will recognize Humphrey’s insightful premises, and will be yet again impressed with the robustness of his positions and ideas. (It is important to point out here that new readers as yet unfamiliar with Humphrey’s substantial body of earlier work will be just as impressed.) The central theme of Seeing Red appears deceptively simple, though it may take a bit of patience initially in order to grasp the implications of the book’s title. The point is that an understanding of consciousness can be inferred from an understanding of what goes into the processes of seeing red (or any other color, for that matter). Further, perhaps, one could say that consciousness and the sense of self are actually products of basic perceptual processing such as seeing red. But seeing red isn’t really as simple as it would appear. One component of seeing red is the primary sensation of it, and another is the viewer’s awareness of this sensation of redness and the perception of the red object or field. However, the human viewer also experiences himself or herself as the subject of the experience. That is, we both experience redness, and are aware of ourselves as the subject that is experiencing redness. Humphrey’s work has long supported an evolutionary process behind consciousness and the sense of self experienced by our species, and this book further develops the foundation for this approach. Whereas it was enough for early organisms to simply respond directly to the environment, evolution has gradually resulted in much more complex, internalized processes in our species (and many others of course). The ability to experience self as both subject and object depends on these processes. The phenomenon known as blindsight illustrates (so to speak) that sensation and perception are co-occurring rather than sequential processes, and thus are more complex than usually thought. Humphrey as a young scientist worked with a monkey whose visual cortex had been removed. As expected, the result of the surgery was apparent blindness. However, Humphrey found over several years that she nonetheless developed an ability to respond to visual presentation. This phenomenon has since been well documented in humans. In conditions where the eyes themselves are intact but the visual pathway or cortex is damaged or destroyed, some human experiencers are unable to “see” (and do report lack of visual experience) while in fact being subtly responsive to visual stimuli or scenes. One infers that there must be multiple pathways from the eyes (and probably other sensory systems) into our neurology, independent of the routes and processes that lead to conscious awareness. But how does this understanding of basic sensory and perceptual processing help us in understanding our type of consciousness? Humphrey explained in a postscript to Seeing Red, When a person smells a rose, he responds to what’s happening at his nostrils with a “virtual action pattern”: one of a set of action patterns that originated far back in evolutionary history as evaluative responses to various kinds of stimulation at the body surface – a form of bodily expression. In modern human beings these responses are still directed to the site of stimulation, and still retain vestiges of their original function and hedonic tone; but today, instead of carrying through into overt behaviour, they have become closed off within internal circuits in the brain; in fact the efferent signals now project only as far as sensory cortex, where they interact with the incoming signals from the sense organs to create, momentarily, a self-entangling, recursive, loop. The theory is that the person’s sensation arises in the act of making the response – as extended, by this recursion, into the “thick moment” of the conscious present; moreover, that the way he represents what’s happening to him comes through monitoring how he is responding. This thick moment (Humphrey’s coinage) is arguably where the self resides, conscious of itself as both subject and object and unbounded in time and space. And why did evolution produce our type of consciousness? Because the sense of self that humans alone experience has been, for our species, adaptive. Humphrey proposes that “Consciousness matters because it is its function to matter. It has been designed to create in human beings a Self whose life is worth pursuing.” Having a self that wants to survive, and that has its “thick moment” in which to internally represent time present and time past, has been an especially effective evolutionary strategy for us. This is the point at which readers will begin to explore those nagging philosophic questions about the meaning of consciousness and self, whether they really matter, if the “self” is only a time-limited if adaptive trick to perpetuate our version of DNA. In response to a plaintive inquiry about whether consciousness could survive physical death, Humphrey once wrote, “Consciousness is something we do with our brains. This is both good news and bad news. The bad news is obvious. The good news is that each moment of consciousness is, as you already know it is, amazingly precious.”
Keith Harris, Ph.D., is Chief of Research for the Department of Behavioral Health in San Bernardino County, California. His current interests include quantitative research with large datasets, behavioral genetics, and the shaping of human nature by evolutionary forces. |