Life permeates the Universe, and is striving to gain a foothold in matter.
George Bernard Shaw
Here we must consider the contentious issue of how the brain and mind relate to one another, if indeed there is any distinction at all. The question is complex, too much so to be given justice here, but essentially, it comes down to the difference between two conflicting interpretations based on 'dualism' and 'materialism'. Dualism, as originally conceived by Descartes, argues that the brain and mind are distinct from one another and interact, allowing for the existence of the soul or spirit. Materialism on the other hand was born out of the conviction that the mind is purely mechanical and non-distinct from the brain itself. Most people, even today, prefer to believe in some form of metaphysical non-materialistic dualism, but this idea has been in decline among academics for the last sixty years, and is dismissed by most contemporary experts on the subject. Even so, it has to be said that proving materialism through mechanical models is extremely difficult, if not impossible; this is reflected in what David Chalmers realistically termed the 'hard problem of consciousness'.
Among materialists, the debate has switched to whether consciousness can be understood in terms of computer programming, or if there is something non-computable about it which cannot be simulated in Artificial Intelligence. Basically, the same old argument, but with the idea of us possessing a soul removed from the equation. Some evolutionists have responded to the limitations of reductionism by adopting vague notions of 'emergence'. It would seem that within science, it is a sin to admit one does not know, therefore we end up with a situation where everyone 'knows' something different - perhaps this in itself tells us something about the nature of consciousness.
Descartes was the first scientist who attempted to seriously rationalise our conscious experience, suggesting a headquarters or central nerve centre as the seat of our mind. Initially, he proposed the pineal gland, based on the fact that it was centrally located and independent of both cortical hemispheres, but he would eventually abandon this idea. The origin of the pineal gland has been explained thus - hundreds of millions of years ago, our reptilian ancestors began to evolve a second pair of eyes on top of the head, presumably as an extra defensive warning system against attack from airborne predators. Before completion, the process was abandoned, leading to the under-developed extra set of eyes fusing with the cerebellum and going underground, so to speak, and leading to the formation of the gland. The pineal gland is often referred to as the 'Third Eye' found in the Sanskrit writings of the ancient Hindus and is associated with E.S.P. by mystics. The gland produces a hormone that affects sleep patterns.
Descartes' conception of a headquarters of consciousness, led to the popular belief in what Dennett refers to as the Cartesian Theatre, where all the various streams of our conscious experience arrive in chronological sequence to be viewed by our inner self; the audience. Dennett argues logically for a 'multiple drafts model', which takes into account the neurological reality of streams of consciousness terminating at various destinations situated around the brain, not necessarily sequentially and therefore termed as temporal and spatial smearing. Our eye movement leads to the perception of an event in one location of the brain; simultaneously, though not necessarily sequentially, memories of similar events are triggered along with descriptive language at separate locations, all these streams being coherently deciphered without ever having to come together in the same location.
What we experience as consciousness in terms of perceiving emotion, sensation, colour, movement and sound, has been designated 'phenomenal consciousness' or 'qualia', and has been considered to be non-impacting on our behaviour, whereas 'access consciousness', relating to acquired information, affects the way we control our behaviour. Subconscious events are taken to be outside of either phenomenal or access consciousness. Phenomenal consciousness has always been considered the most mysterious and inexplicable aspect of our mind's functionality and beyond neurological explanation. Non-materialists, such as John Eccles, considered phenomenal consciousness as being epiphenomenal; using the word in the sense that consciousness could not have been the product of natural selection and can never be fully explained in scientific terms. 'Heterophenomenology', as advocated by Dennett, denies the differentiation of qualia and considers all conscious functionality to be accessible, thereby removing any problem in explaining the totality of our consciousness in evolutionary terms. Heterophenomenology has been criticised for oversimplifying the issue and only addressing the easier problems of consciousness, but at least Professor Dennett has undoubtedly shown that at least some aspects of consciousness are not necessarily so mysterious as to be beyond the powers of explanation.
It has been said that the problem with this traditional argument about consciousness is that it has been going on since the days of Lock and Hume, without promising any satisfactory conclusion.
Quantum theories of consciousness have created even more divisions amongst the scientific community. Some physicists consider the idea to be a myth. Victor J. Stenger says:
'If Bohr and Heisenberg had spoken of measurements made by inanimate instruments rather than 'observers', perhaps this strained relationship between quantum and mind would not have been drawn.'
Just when biologists thought they had finally put the dualistic 'ghost in the machine' to bed, along came some quantum theorists to spoil things. In the words of Christof Koch and Klaus Hepp:
'Physicists, ignorant of modern neurobiology, are tempted to assume a formal or even dualistic view of the mind-brain problem.'
Some scientists are sitting on the fence and hedging their bets, whilst others remain skeptical, but open-minded. The best known and most fascinating theory of quantum consciousness is the 'orchestrated objective reduction' theory, jointly formulated by Roger Penrose and Stuart Hameroff. The theory is based on the non-computability of the mind and converges somewhat with Chalmers 'naturalistic dualism'. The quantum event chosen is Bose-Einstein condensates occurring in tubulin within neurons - problems concerning brain temperature may be overcome, but ultimately the theory relies on a yet to be formulated theory of quantum gravity. More conservative and classical-minded physicists aim to bring quantum consciousness within the parameters of monistic non-reductive physicalism, based on quantum entanglement. Yet others prefer to study wave particle duality in relation to quantum consciousness.
If we approach the emergence of consciousness from an evolutionary point of view, implying that the mind and brain are non-distinct from one another and subject to the same evolutionary processes as the rest of the body, we can consider our self-awareness as the inevitable result of the evolution of life in general. The process could have begun with complex macromolecules evolving the ability to act purposefully, as in Dennett's 'birth of agency'. The next stage could have involved single cell organisms developing a primitive form of consciousness - natural selection favouring organisms with the ability to make choices, as suggested by Marguilis and sagan. Such ability remained primitive in terms of consciousness, in the sense that computers are able to make choices. The motivating factor for the selection of such behaviour may have been its success in relation to the dynamics of predator-prey relationships, as postulated by Baringa, allowing an organism to avoid simply bumping into another organism which would devour it. The ongoing development of conscious experience could have been stimulated in terms of sensations, like pain and a sense of fear, motivating an organism to avoid life-threatening situations, along with a sense of taste providing a stimulus to find nourishment and pleasurable sensation, providing a reward for expending energy on reproduction, (Chalmers), the latter consideration having been taken to the extreme in humans.