The last few issues of the THES have seen a number of writers from many disciplines attempting to solve the problem of consciousness. Molecular geneticists, quantum theorists, mathematicians, cognitive scientists, neuro-physiologists, and artificial intelligence workers - all have a finger in the pie. And apparently for one `impure philosopher', Daniel Dennett, consciousness has been explained. Yet for many `pure' philosophers the problem seems as difficult as it seemed to the great philosophers of the past.
The problem concerns the nature of consciousness, and has at its heart a metaphysical assumption made by these various, largely non-philosophical writers; seduced by the success of physical science, they assume that nothing exists but physical entities and their properties. (As we shouldn't tie ourselves to a particular scientific theory, `physical reality' can be taken to mean the sum total of the ontological commitments physical science would accept.) What is meant by `physical' would be a way of describing the world which makes no reference to the point of view from which that description is given - to the subject. The deepest motivation for attempting to explain consciousness through brain processes seems to derive from a certain ontological intuition: given that what is respectable and rigorous is what is physical, scientifically explainable, there is no place for the subject (or the mind, or consciousness). In some cases there isn't any ontological commitment: all we're supposed to need is a systematic explanatory theory. But is such an intuition correct? And are there cogent independent reasons for accepting these explanations?
The problem is not whether consciousness can be explained in terms of or reduced to the physical; it contains at its heart a double challenge. Whatever equations a neuroscientist or other expert theorist may develop, whatever physical resolutions they advance, the phenomenon of consciousness will always remain: our understanding of consciousness (however vague, inadequate, or confused) is something that has to be presupposed if such theories are not to be left spinning in a void. Reductive or eliminative theories involve stripping off the leaves to find the real artichoke - but what is left is no longer an artichoke. I don't deny that these theories might succeed in explaining the workings of the brain. I do deny that such explanations would provide us with a picture, let alone the complete picture, of what consciousness is. Implicit in this denial is the first challenge confronting these theorists: how can what is left possibly add up to, constitute, result in consciousness? A satisfactory answer should enhance our conception by rejecting any attempt to understand consciousness in terms of theories that presuppose the answer to the central question.
All this might leave the various theorists unmoved; they might argue that the problems I raise are pseudo-questions - that I treat them as genuine philosophical questions only by refusing to accept their theories, leading me to make claims which are fundamentally misguided. Whatever the answer to such arguments, we are still faced with an independent problem about consciousness. This brings me to the crux of the matter. The different areas of discourse which attempt to explain consciousness all adopt purely third-person approaches. They develop theories, set up experiments, work out hypotheses, thrive on models and metaphors. A theorist might identify the different brain states, neurons, etc., constructing statements such as `consciousness is xyz', like `water is H2O', giving a complete explanatory theory of the brain. But even if it turns out to be just a matter of equations (although the first challenge must be answered before we accept them), there is still something left unaccounted for: the first person. It is the phenomenon of the first person itself that poses the second, clearest, and greatest challenge to the idea that these theories will give the general form of consciousness. The first person just is the anchoring point of each subject's system of self- reference, tying his concepts to objects in the world. It is precisely this phenomenon that is at the root of the irreducibility of consciousness, since no adequate conception of the phenomenon can be given in any explanatory theory without abandoning it or explaining it away.
Giving a complete explanatory theory of the brain does not imply anything about what it is to be conscious. What it is to be conscious is not a matter of equations, however compli- cated. It is rather to have passed over from the condition of the observer - the theorist - to the condition of the conscious subject. Now it might still be objected this time by some pure philosophers that the problem is unreal, and that the sense of irreducibility that I am defending is based on a misunderstanding: a confusion about the (Fregean) sense and reference of terms. But, and I am sure Frege would have agreed, this is where the analogies based on and the equations drawn from the discoveries of other physical entities collapse: there is no subject, no first-person mode of apprehension to be accounted for in water, in neurons, or in particles. That is why statements like "`You', your joys, and your sorrows [...] your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules" (Francis Crick, The Astonishing Hypothesis - THES 27.5.94) are simply fallacious. Statements, especially in this area, that contain phrases like no more than, or nothing but, almost invariably beg some fundamental question.
What distinguishes us from other natural-kind entities in the world is precisely our first-person perspective, the conceptual capacity to self-identify and self-ascribe. It is this capacity which promises a metaphysical underpinning of the view that we are in the physical world but at the same time resist reduction to or elimination from any description of it. Thus any attempt to reduce, eliminate, or ignore the first person by adopting the third-person perspective of science would be an attempt to erase consciousness itself. The irreducibility thesis I am upholding does not demand the priority of the first person, being based on a symmetrical metaphysics of subject and world, for our first-person mode of apprehension is not unaffected by the external world. The issues here are very complex and take me beyond the scope and limits of this article.
Philosophers like Descartes, Hume, and Kant realised how difficult the problem of consciousness really is. Having concluded that `I am nothing but a bundle of perceptions', Hume had the intellectual honesty to recognise - and lament in the Appendix - his inability to account for the very thing that had led him to that thesis: the self. It is the self (the subject, the `I', the first-person mode of apprehension) that is so adept at slipping through the nets of the various theories of expertise. Contemporary theorists, jumping on the bandwagon of consciousness, try to show how such a difficult problem can be sidestepped. They fail to convince us, for in their attempts to sidestep the problem, they sidestep the phenomenon of consciousness itself.
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