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Evidence for a Materialist Theory of Mind by Sadiqi az-Zindiki As the domain of scientific explanation for natural phenomenon expands, it becomes commensurately less fashionable to attribute supernatural causation to what hitherto may have held greater mystery. A phrase has even been coined associating supernatural hypotheses with human ignorance: �the god of the gaps.� In the field of neuroscience, that phrase might be better rendered as �the soul of the gaps.� The supposition that if present day science cannot explain to total satisfaction the conundrums of self-awareness or the precise functioning of a memory formation there must be a transcendent element of the mind to fill in the blanks is a logical fallacy. The burden of proof is on the claimant. The immaterial soul does not become true by default. Indeed, materialist theories of mind have corroboration at both the macroscopic and microscopic levels � such that any theory of mind (with or without reference to a �soul� of some variety) would have to take into account the �circumstantial� gelatinous substances found in just an occasional cranium. Though much of the brain may still remain a black box opaque to human understanding, the materialist research project is not without its successes. Without making detailed reference to the history of neuroscience, the ability to find out details of cognition rests largely on the methodology of reductionism coupled with empirical tools for sensory enhancement. Taking a reductionistic-eye view, the mammalian brain is a control mechanism made up of specialized tissues and topographies linked up via the spinal cord to the ends of the body (cf. for control mechanism, Cziko, 2000, p.68-107). The brain can be subdivided into functional sub-organs like the hypothalamus, amygdala, and cerebral cortex. The cerebral cortex can then be further subdivided into modules of known function, such as speech processing or visual interpretation (though such a representation of the specialization of �labor� is not as discrete as a phrenologist�s map� e.g. an area may be associated with language but also be associated with facial movements, cf. Calvin, 1996, p.100). The gelatinous blob of yesteryear becomes a manifold agglomeration of specialized inter-networked cells. Those cells in turn are found to communicate through electro-chemical potentials and neurotransmitters. Instead of nebulous holistic mysteries, the ability to �divide and conquer� using different powers of magnification results in scientific problems that hold the possibility of solution. While science might not methodologically be able to disprove the set of all �theories� of soul, there is sufficient evidence to indicate that mind-brain or mind-body distinctions may not be as significant as has been thought. Recapitulating the words of Laplace in a new context, there is �no need of that [non-materialist] hypothesis.� Science offers probabilistic reasoning, not indelible certainties. That said, to speak of disproving the soul is a lot like disproving that at the center of each black hole is an invisible tootsie pop, or that when no observer, mechanical or otherwise, is looking, all non-observed matter morphs into physics-defying, immortal quantum sugarplums. Ludicrous as these statements sound, and unlikely from past inductive experience, it would be a feat to create an eliminative test. As such, reasons for not accepting the soul are more philosophical � the internal logic postulated for the soul may be contradictory (e.g., how do Siamese twins� souls interact) or the hypothesis in question may conflict with aspects of human identity that can be tested (e.g., human sexual predilections may be at a variance with the �natural� order assumed by the writers of the Bible and the Qur�an). To take one objection that comes to brain: �The traditional explanation of intelligence is that human flesh is suffused with a non-material entity, the soul, usually envisioned as some kind of ghost or spirit. But the theory faces an insurmountable problem: How does the spook interact with solid matter?� (Pinker, 1997, p.64) As Pinker notes, the immaterialist position must first attempt to find a place (�noplace?�) in physics (or beyond) for the non-material before attributing the non-material to a neurological process. Even if the non-material had somehow been verified by physics the immaterialist would have a new problem � selecting from the historical grab bag of souls one consonant with the evidence. The multiple, mutually contradictory accounts of the immaterial soul make it requisite for proponents to eventually make a scientific case for their version -- whether Cartesian dualist, jiva pantheist (reincarnated), or animist. If, on the other hand, they say it is unverifiable, not falsifiable, insoluble to reason, or must be taken on faith, a non-materialist hypothesis will never become a scientific theory. Whether maintaining the �prerogative� of faith or not, however, religious or philosophical claims about human identity may still be subject in part to a critical scientific examination, insofar as faith claims differ or coincide with parsimonious and empirically validated explanations. If a religious leader attributes mental illness to demon possession, the twin blades of Ockham�s razor and Galileo�s knife may provide alternate etiologies in contradiction to the faith claim. Instead of proclaiming the same etiology as Linda Blair and her pea soup, a scientific approach would try to isolate correlations between socioeconomic and physical variables. This is not to say that science can�t confirm a faith claim either: if a hypothetical �holy� text states that the brain is the fons et origo of cognition, a scientific examination may lend more support to that holy text on that point than to another faith claim that cognition takes place in the heart. Reducing the permutations of soul espoused by sects and philosophers to a composite, however, it�s not difficult to determine that non-materialist theories would likely meet with greater popularity among general populations � scientifically supported or not. The soul has the force of thousands of years of tradition and in some metaphysics carries with it the enticements of blissful immortality. Additionally, human subjective experience is one of being in the �driver�s seat,� and no amount of reference to biochemistry or evolution may take away the feelings of personal incredulity that on an argumentative level may lead to a logical fallacy. (If, for example, a lack of rigorous understanding prevents many from understanding how natural selection could account for the spectacle of biodiversity, that emotive incredulity does not substitute for finding an inconsistency in that theory, and/or a better theory.) By way of contrast, the theory of material mind offers the boon of death everlasting and non-intuitive notions of human will (viz., it�s an illusion in a universe determined by matter, and particle randomness). Although to determine what shapes folk psychology is another line of research entirely, it�s not difficult to see how the materialist theory may more easily presented as �cold� by the entrenched traditions that rest on �saving souls.� The side effects of having pragmatic theories of mind, including anti-depressants, mood stabilizers, anti-seizure agents and electro-convulsive therapy apparently do not dispense popularity on the materialist theories, even if it is difficult to find any such fruits for immaterialist theories. The beneficial applied science that results from theoretical models of the material mind can be dismissed as readily as some people thank the supernatural for what can more directly be attributed to human effort and perseverance (e.g. the birth of multiples by fertility drugs is not often greeted with praise to pharmaceuticals). Clearly, an independent investigation must attempt to detach from the prominent value-laden concepts of human identity. Pascalian wagers carry with them anthropocentric presuppositions that echo the past justifications for geocentrism, and denial of common descent. Unlike stars or amoebas, by some providence, individual Homo sapiens will never be extinguished. The 100% death rate magically becomes its antithesis. Quite apart from human hopes and ingrained beliefs, is the question of which approach best explains the multidisciplinary observations of neurology, psychology, psychiatry, and animal research. Ethics dictate that neuroscience researchers cannot perform invasive and damaging procedures on humans to test all facets of the materialist theory, so the evidence for the material mind comes largely from natural experiments and the human penchant for mind altering substances (though with positron emission topography, magnetic resonance imaging and other non-invasive techniques for observing living tissue, limitations on controlled experiments are diminishing). By natural experiment, it is typically meant that a pre-existing medical condition results in an abnormal mental state, which if isolated enough (to act as a natural control) may provide insight into the function of the destroyed or altered brain areas. The ubiquitous textbook example cited in demonstrating personality alteration is the 1848 accident of Phineas Gage:
If there was only a certain set of social behaviors capable of deletion, immaterialists would have a wider gap to place their single syllable hypothesis. But other aspects of the mind are just as capable of deterioration and deletion, among them memory. Neurodegenerative illnesses and syndromes like Alzheimer�s, and to a lesser extent Parkinson�s disease (PD), have been repeatedly shown to affect memory, along with other cognitive processes. The two syndromes are thought to �share some aetiological factors which may represent interactions between the ageing process, environmental factors and specific genetic, toxic, infective and other factors.� (Mindham & Hughes, 2000, p.281). Though the precise mechanisms have not been worked out to the degree of organic brain disorders like phenyl ketonuria, Mindham and Hughes go on to describe anatomical irregularities associated with PD: �The basic lesions are the degeneration of the pigmented neurons in the pars compacts of the substantia nigra in the brain stem, the presence of Lewy bodies and accompanying gliosis.� In simpler language, the brains of PD sufferers look funny, and the pathology is indication of a material disease process. As human beings are not content losing their brain cells by accidents of fate, more examples of the mind being changed by physical processes can be furnished from the pharmacy of �feel good.� Reference books are crammed to the brim with mind altering substances humans are willing to snort, sniff, smoke, inject, and digest. One of the most popular, of course, is alcohol. The temporary effects of the most popular depressant are well known to many from first hand experience. But for habitual over-abusers, the change in brain chemistry and corresponding changes in mind go far beyond simple relaxation and loss of inhibitions:
The ability for brain damage and chemical exposure to radically alter behavior, memory, and perception, is wholly consistent with the mind being materially dependent on the brain. That physical changes to the macroscopic and microscopic structures of the brain can result in profound deficits and/or alterations of abilities creates a problem for some formulations of the soul. So far there is no evidence for any indestructible components of the mind, and so there is no reason to think the human self can be isolated from the nervous system. These bare and blunt facts amount to just one of the planks of the developing materialist theories of mind. References
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