Are Neuroscientists Able to Explain Human Consciousness - Essay Example

Running Head: This house believes that neuroscientists will never be able to explain human consciousness This house believes that neuroscientists will never be able to explain human consciousness Authors Name Institution Name It would be an exaggeration to say that neuroscientists have no clue whatsoever to how consciousness is possible. In fact, neuroscientists have certain facts at hand that give them a hint. As whatever consciousness ultimately might be, it is somehow based on the workings of the central nervous system. This is something humans have not always known: For Aristotle, it was the heart, not the brain that was the seat of human mental life. In fact, Aristotle explicitly denied that the brain could be the sensory center. For centuries, the brain was considered to be a relatively unimportant organ, the main purpose of which was to cool the blood. By contrast, at present the brain is the most complex chunk of ordered material we have encountered in the universe so far. Consequently, perhaps it is not such a great miracle that that sort of a setup can give rise to something as peculiar as consciousness. Human conscious lives are the sea in which they swim, they consciously experience many different things, and they can think about the things that they experience. But it is not so easy to experience or think about consciousness itself. Given this, it is common within philosophy and science to identify consciousness with something smaller than itself, for example with some thing that we can observe, such as a state of the brain, or with some aspect of what they experience, such as ‘thought’ or ‘language’. Thus neurobiologist is the one who specializes in the study of the brain who can understand consciousness without reducing it in any way. Before the advent of modern neuroscience, consciousness was a subject for philosophical debate or qualitative psychological descriptions based on introspection. In some schools of psychology, such as behaviorism, it was placed outside of the scientific program, and considered to be a kind of epiphenomenon. More recently, cognitive psychologists have taken certain functional aspects of consciousness as neurally unanalyzed bases for their studies on human perception and even with a certain degree of success. Such a position does not go far enough, however. Any attempt to account for higher brain functions in terms of the physical organization of the brain itself and of its constituent neurons is confronted sooner or later with the need for a detailed analysis of consciousness based on brain structure. Neurobiologists begin to define ‘Consciousness’ ostensively by contrasting situations where it is present and absent—for example, situations where one is conscious of something as opposed to not being conscious of that thing. That is, consciousness can partly be defined in terms of the presence or absence of phenomenal content. ‘Mind’, by contrast, refers to psychological processes that may or may not have associated conscious contents. There is considerable evidence, for example, for a ‘cognitive unconscious’. And ‘soul’ traditionally refers to some essential aspect of human identity that survives bodily death. Another relatively safe bet is the claim that the way in which the world is modeled by an organism in its conscious experience has been biologically useful for the creature in its evolutionary history. This phenomenological model of the world has improved the likelihood of the organisms survival and the production of offspring more than other kinds of phenomenological organization have done or the absence of conscious experience could have done. Although it is difficult to trace the evolution of consciousness as long as we do not know the neurobiology on which it is based, it is encouraging that even ethologists have started to take the animals point of view and talk about their mental states and consciousness (Cheney & Seyfarth, 1990). Although philosophers never abandoned talk about consciousness quite as completely as did neuroscientists, consciousness was rarely treated explicitly as the main topic during the murky days of behaviorism. Identity theorists, by contrast, unashamedly asked the question, "Is Consciousness a Brain Process?" (Place, 1956). The three most prominent manifestations of the problem were the recurrent discussions and arguments about subjectivity, qualia, and intentionality. Perhaps the most remarkable landmark of the consciousness and subjectivity as the main focus of the philosophy of mind was the publication of Thomas Nagel classic article, "What Is It Like to Be a Bat?" in 1974. In this article, Nagel analyzed what it means for an organism to have conscious experiences: "An organism has conscious mental states if and only if there is something it is like to be that organism; something it is like for the organism" ( Nagel, 1974, p. 436). Moreover, he claimed that the various attempts to reduce mental states to this or that had all been unsuccessful, because they all ignored this subjective character of conscious mental experiences. By qualia, philosophers mean those properties of conscious experiences that define what the experience feels like for the subject. The taste of chocolate, the itch of a mosquito bite, the heat of the sauna, the shrill, chirping noise of a grasshopper, and the pale, yellowish glow of the full moon are qualitative properties of conscious experiences. The external physical causes of such experiences, the behavioral responses associated with them, or the neural impulses in the brain underlying them seem to be only accidentally connected with the experiences themselves. The qualia, by contrast, seem absolutely essential for the conscious mental states to exist at all. (Block, 1980a, 1980b; Jackson, 1982) The third important connection to consciousness came through intentionality, which was perhaps the central problem of the philosophy of cognition throughout the 1970s and 1980s. This was because the central concepts of cognitive science--like representation, belief, and perception--were intentional notions in the sense that such states are directed at objects and states of affairs in the world. The main task was to determine how intentional states can stand for something outside of themselves; how they can have content or semantics. The philosopher John Searle ( 1980) made a distinction between intrinsic intentionality and observer-relative ascriptions of intentionality : Only mental states can have intrinsic intentionality, but beings with intrinsically intentional mental states can ascribe observer-relative intentionality to any systems they like to treat as if having beliefs, perceptions, or representations. However, true intentionality has, according to Searle ( 1979), a necessary connection to consciousness: Only beings capable of conscious states can have intrinsically intentional states. Thus, Searles idea was that only conscious beings can really perceive, understand, represent, or believe anything. Nevertheless, most of the work on intentionality had been made completely disregarding its connections to consciousness, and later Searle ( 1989, 1990, and 1992) launched a major attack against cognitive science ignoring consciousness. At the end of his Psychology: Briefer Course, James remarked, Something definite happens when to a certain brain-state a certain "sciousness" corresponds. A genuine glimpse into what it is would be the scientific achievement, before which all past achievements would pale. But at present, psychology is in the condition of physics before Galileo and the laws of motion, of chemistry before Lavoisier and the notion that mass is preserved in all reactions. The Galileo and the Lavoisier of psychology will be famous men indeed when they come, as come they some day surely will, or past successes are no index to the future. When they do come, however, the necessities of the case will make them "metaphysical." Meanwhile the best way in which we can facilitate their advent is to understand how great the darkness in which we grope is, and never to forget that the natural-science assumptions with which we started are provisional and revisable things. In the 1960s, another kind of evidence started to accumulate in neuropsychology that raised considerable speculation concerning the nature of consciousness. In short, it seemed very likely that a surgical division of the brain by the midline section of the cerebral commissures entailed a co-occuring division of the mind and consciousness. The cerebral hemispheres of these split-brain patients were separated from each other by sectioning the corpus callosum and other commissures that normally combine the hemispheres. Usually this was done in order to tame an unbearably violent case of epilepsy. After the operation, the patients normally recovered well, and nothing unusual could be noticed in their everyday behavior. However, in controlled laboratory tests split-brain patients manifested surprising dissociations of mental processes. A common experimental setting was something like this: The patient was asked to fixate his gaze onto the center of a screen. After that, two words were briefly flashed on the screen so that one of them was to the left of the patients fixating point and the other to the right. The exposure time was so short that it was impossible for the subject to scan the words with several fixations. Thus, it was ensured that from the left visual field information goes only to the right hemisphere and from the right visual field to the left--the projection areas are always in the contralateral sides of the brain. Split-brain research is a fine specimen of astounding empirical studies that made neuroscientists philosophize about consciousness and after a time-lag of some years for the news to spread, forced philosophers of mind to get acquainted with actual experimental settings and results. No general agreement was ever reached: Almost every possible interpretation of the phenomena had its own supporters. Thus, the pioneering neurophysiologist and Nobel laureate Roger Sperry argued that there are two independent minds, two actual streams of, consciousness flowing inside the split brain (Sperry, 1984). Another researcher in the field, Michael Gazzaniga, was more inclined to allow conscious status only to the verbally behaving left hemisphere ( Gazzaniga, LeDoux, & Wilson, 1977). But philosophers joined this game of mind counting and came up with even more incredible answers. Thomas Nagel ( 1979) concluded that "there is no whole number of individual minds that these patients can be said to have" (p. 163). Charles Marks ( 1981) favored a one-mind account of split-brain patients, although, he claimed, a two-mind account could not be rejected on logical grounds alone. Roland Puccetti ( 1981) argued that, in fact, each hemisphere has a mind of its own not only after commissurotomy but also normally for all of us, all of the time. Patricia Smith Churchland ( 1981) criticized this whole debate, pointing out that the paucity of theories concerning consciousness makes it difficult to know what the discussion is all about. She suggested that "being conscious" is at this stage of mind-brain science theoretically so ill-defined that counting centers of consciousness in the brain is a bit like asking how many angels can dance on the head of the pin or how many vital spirits pervade living organisms. In a nutshell, consciousness survived in neuroscience in the form of the annoying problems of subjectivity, qualia, and (intrinsic) intentionality. At the same time, it started to raise its head among neuroscientists as a consequence of curious experimental results that demanded theoretical interpretations in terms of subjective experience. Reference: W. James, Psychology: Briefer Course ( New York: Henry Holt, 1893), 468. Cheney D. L., & Seyfarth R. M. ( 1990). How monkeys see the world: Inside the mind of another species. Chicago: University of Chicago Press. Place U. T. ( 1956). "Is consciousness a brain process?" British Journal of Psychology, 47, 44-50. Nagel T. ( 1974). "What is it like to be a bat?" The Philosophical Review, 83, 435-450. Nagel T. ( 1979). "Brain bisection and the unity of consciousness". In T. Nagel (Ed.), Mortal questions (pp. 147-164). London: Cambridge University Press. Block N. ( 1980a). "Troubles with functionalism". In N. Block (Ed.), Readings in philosophy of psychology (pp. 268 -306). Cambridge, MA: Harvard University Press. Block N. ( 1980b). "What is functionalism?" In N. Block (Ed.), Readings in philosophy of psychology (pp. 171 - 184 ). Cambridge, MA: Harvard University Press. Jackson F. ( 1982). "Epiphenomenal qualia". Philosophical Quarterly, 32, 127-136. Searle J. R. ( 1979). "What is an intentional state?" Mind, 88, 72-94. Searle J. R. ( 1980). "Minds, brains, and programs". Behavioral and Brain Sciences, 3, 417-457. Searle J. R. ( 1989). "Consciousness, unconsciousness, and intentionality". Philosophical Topics, 18, 193-209. Searle J. R. ( 1990). "Consciousness, explanatory inversion and cognitive science". Behavioral and Brain Sciences, 13, 585-642. Searle J. R. ( 1992). The rediscovery of the mind. Cambridge, MA: MIT Press. Sperry R. ( 1984). "Consciousness, personal identity and the divided brain". Neuropsychologia, 22, 661-673. Gazzaniga M. S., LeDoux J. E, & Wilson D. H. ( 1977). "Language, praxis, and the right hemisphere: Clues to some mechanisms of consciousness". Neurology, 27, 1144-1147. Puccetti R. ( 1981). "The case for mental duality: Evidence from split-brain data and other considerations (with commentary)". Behavioral and Brain Sciences, 4, 93-123. Churchland P. S. ( 1981). "How many angels...?" Behavioral and Brain Sciences, 4, 103 - 104. Marks C. E ( 1981). Commissurotomy, consciousness & unity of mind. Cambridge, MA: MIT Press. Read More