Consciousness
Something is conscious if there is something that it is like to be that thing. This widely accepted definition, proposed by philosopher Thomas Nagel (1974, reprint 1997 p. 519), emphasizes the subjective character of conscious experience, which is the fundamental obstacle to its scientific investigation. Scientists have no objective access to conscious states (even their own) so consciousness can only be studied scientifically by indirect means, and some believe that a complete scientific description of the world can and should be made without reference to consciousness at all. However to exclude conscious decisions from the causal chain of events would undermine all ethical and legal systems based on personal responsibility for consciously willed actions.
In the 1980s, neurophysiologist Benjamin Libet showed that when subjects were asked to make a voluntary movement at a time of their own choosing, brain activity initiating the movement (the readiness potential) routinely preceded by about half a second the conscious decision to make the action. Many people interpreted this as scientific proof that conscious choice and freewill are illusory, which would fit with the view that the physical universe is causally closed and deterministic. Libet himself safeguards personal freedom of action by arguing that although the brain's non-conscious readiness potential initiates an action, there is still time for the conscious mind to monitor and abort the process before the action is carried through.
Libet's work was an early example of scientific research into consciousness that combines objective information about brain activity with subjective reports from experimental subjects concerning their conscious states. Earlier generations had been handicapped by the need to choose between subjective and objective methods. Typical of these were introspectionism, pioneered by German psychologist Wilhelm Wundt (1832–1920), which depended on individuals analyzing their subjective thoughts, feelings, and perceptions into thousands of basic mental sensations, and the behaviorism of John Watson (1878–1958) and his successor B. F. Skinner (1904–1990). Watson rejected introspection, maintaining that if psychologists wanted to be real scientists they must study objective, verifiable data, which meant observable behavior. Such was his influence that consciousness was effectively banned from psychology for half a century in the mid-1900s.
The scientific study of consciousness was rehabilitated in part by new technologies that allowed the working of the brain to be objectively studied while mental processes were being carried out. The electroencephalogram (EEG), recording electrical activity in the brain, was available from the 1930s and used by Libet among others. Brain scanning techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), developed in the 1980s and 1990s, enabled detailed observation of active areas of the brain at work and confirmed the hypothesis that mental states are closely related to the physical condition of nerve cells (neurons). Neuroscientists were now able to observe the areas of neural activity associated with particular conscious experiences reported by human subjects, or deduced from the behavior of animals such as monkeys. Various systems in the brain were investigated, from individual cells to large networks and pathways of interconnected neurons, in the quest to identify possible neural correlates of consciousness (NCCs).
The exact relationship between conscious experience and the physical brain, and how and why some brain processes are conscious at all, is the core dilemma. David Chalmers, Director of the Center for Consciousness Studies at the University of Arizona at Tucson, has dubbed it the Hard Problem. In the mid-twentieth century the influential Oxford philosopher Gilbert Ryle (1900–1976) dismissed Descartes's dualist concept of mind-body relation as the ghost in the machine, and opened the way for various materialist accounts of consciousness. By the turn of the millennium most consciousness researchers embraced some form of non-reductive materialism, which holds that mental states are wholly caused by the physical brain, but have some quality over and above the sum of their molecular components. Variations on this theme include property dualism (mental states exist as properties of underlying physical states), dual aspect monism (the mental and the physical are two ways of looking at a single underlying reality), emergentism (consciousness emerges at a certain level of complexity), and panpsychism (every material object has an actual or potential degree of consciousness).
Treating consciousness as a real aspect of the physical world brings it back into the realm of scientific inquiry and removes the suggestion that it is an epiphenomenon, lying outside the causal nexus of the universe. But it does not automatically refute the claim that free choice and moral responsibility are delusions. The physical world of which consciousness is a part still appears to be deterministic, at least according to classical physics. Researchers into artificial intelligence, for instance, have drawn parallels between neuronal activity in brains and the processing of information in computers The question of whether the conscious mind itself is computational, that is, completely describable mathematically and therefore in deterministic terms, is hotly disputed.
Deterministic views are challenged within science by evidence from quantum physics, although its relevance is disputed and some of the claims speculative. For example, Oxford mathematician Roger Penrose proposes that in certain special conditions, found in the microtubules within brain cells, quantum systems provide the physical mechanism that brings about noncomputational conscious events. From a different starting point, Berkeley physicist Henry Stapp argues that quantum theory can explain how consciousness plays a creative role in shaping events and creating the world as humans know it. These views are frequently criticized, but at the very least, quantum theory puts a large question mark over the old assumption that the universe is a collection of objective facts that are (in theory at least) completely knowable.
Consideration of the ethical questions posed by the investigation and manipulation of consciousness falls under the sub-discipline of neuroethics. But the challenge to produce an account of conscious experience that provides an adequate basis for morality at all, and is at the same time both philosophically and scientifically robust, lies at the heart of all consciousness studies.
Bibliography
Chalmers, David J. (1996). The Conscious Mind: In Search of a Fundamental Theory. New York: Oxford University Press. A technical book, written by a philosopher making use of scientific research, mostly accessible to the general reader. The stance is non-reductive physicalism.
Dennett, Daniel. (2003). Freedom Evolves. New York: Viking Press. A representative title from many by this popular philosopher of mind. Written from a reductive viewpoint for both professional and general readers.
Freeman, Anthony. (2003). Consciousness: A Guide to the Debates. Santa Barbara, CA: ABC-CLIO. A non-technical introduction that includes extracts from classic texts.
Libet, Benjamin; Anthony Freeman; and Keith Sutherland, eds. (1999). The Volitional Brain: Towards a Neuroscience of Freewill. Exeter, UK: Imprint Academic. Collected essays by scientists and philosophers.
Nagel, Thomas. (1974). "What Is It Like to Be a Bat?" Philosophical Review 83(4): 435–450. Reprinted in the 1997 book The Nature of Consciousness: Philosophical Debates, eds. Ned Block, Owen Flanagan, and Güven Güzeldere. Cambridge, MA: MIT Press. A seminal paper raising the need for philosophers to address subjectivity.
Popper, Karl, and John Eccles. (1983). The Self and Its Brain: An Argument for Interactionism. London: Routledge. Two eminent authors make the case for the unfashionable dualist approach to mind-body interaction.
This is the complete article, containing 1,186 words
(approx. 4 pages at 300 words per page).
