In the 1950s materialistic philosophy was carried to a new extreme in the so-called 'psychophysical (or mind–brain) identity theory'. By involved semantics it was affirmed that no difference exists at all between mind and brain, that they are one and the same, and only seem like two different things because we have used different languages and perspectives in our objective and subjective descriptions. According to this identity theory, there is no mind–brain relation; only a pseudo-problem remains that allegedly can be resolved with a proper linguistic approach. The materialist position as developed through the late 1960s was expressed by D. M. Armstrong, a leading proponent, as 'the view that we can give a complete account of man in purely physico-chemical terms', in a 'purely electrochemical account of the workings of the brain'. 'The mind is nothing but the brain.' 'Life is a purely physico-chemical phenomenon.' 'It seems that man is nothing but a material object having none but physical properties' (Armstrong 1968). The accepted superfluousness of consciousness for neuroscience was expressed by Nobel laureate Sir John Eccles in 1964:
- We can, in principle, explain all our input–output performance in terms of activity of neuronal circuits; and consequently, consciousness seems to be absolutely unnecessary! ... as neurophysiologists we simply have no use for consciousness in our attempts to explain how the nervous system works.
The neural infrastructure of any brain process mediating conscious awareness is composed of elements within elements and forces within forces, ranging from subnuclear and subatomic particles at the lower levels upward through molecular, cellular, and simple-to-complex neural systems. At each level of the hierarchy, elements are bound and controlled by the enveloping organizational properties of the larger systems in which they are embedded. Holistic system properties at each level of organization have their own causal regulatory roles, interacting at their own level and also exerting downward control over their components, as well as determining the properties of the system in which they are embedded. It is postulated that at higher levels in the brain these emergent system properties include the phenomena of inner experience as high-order emergents in the brain's hierarchy of controls.
Interpreted as holistic high-level dynamic properties, the mental phenomena are conceived to control their component biophysical, molecular, atomic, and other sub-elements in the same way that the organism as a whole controls the course and fate of its separate organs and cells, or just as the molecule as an entity carries all its component atoms, electrons, and other subatomic and subnuclear parts through a distinctive time–space course in a chemical reaction. As is the rule for part–whole relations, a mutual interaction between the neural and mental events is recognized: the brain physiology determines the mental effects, as generally agreed, but also the neurophysiology, at the same time, is reciprocally governed by the higher subjective properties of the enveloping mental events. These interact at their own level and correspondingly move their subsidiary constituents in brain processing. Although determined in part by the properties of their neural components, the subjective properties are also determined by the spacing and timing of the components. Thus the critical, multinested space–time pattern properties of the neuronal infrastructure, as well as the mass–energy elements, must also be included in the causal account.
The resultant mind–brain model, in which mind acts on brain and brain acts on mind, is classified as being 'interactionist' in contrast to mind–brain 'parallelism' or mind–brain 'identity'. The term 'interaction', however, is not the best for the kind of relationship envisaged, in which mental phenomena are described as primarily supervening rather than intervening, in the physiological process. Mind is conceived to move matter in the brain and to govern, rule, and direct neural and chemical events without interacting with the components at the component level, just as an organism may move and govern the time–space course of its atoms and tissues without interacting with them.
In the revised mind–brain model consciousness becomes an integral working component in brain function, an autonomous phenomenon in its own right, not reducible to electrochemical mechanisms. Exerting top-level causal influence in the direction and control of behaviour, the conscious mind is no longer something that can be ignored in objective neuroscience wherever an explanation of conscious activity is concerned. Subjective experience is given a use and reason for being as having a central, ineliminable causal role in brain function. A rationale is thus provided for the evolution of mind in a physical world.
The new mentalist view of consciousness as causal stands in direct opposition to the founding precepts of the behaviourist–materialist philosophy. The two explanatory frameworks are diametrically opposed and mutually exclusive. During the 1970s in the so-called 'consciousness' or 'mentalist' revolution (referred to also as the 'cognitive', 'humanist', or 'third' revolution), the new mentalist interpretation gained acceptance over behaviourism as the dominant paradigm of psychology. The shift from behaviourism to mentalism, or cognitivism, represents a shift to a fundamentally different form of causal determinism. The traditional micro-determinism of the materialist–behaviourist era, emphasizing causal control from below upward, gave way to a paradigm in which primacy is given to emergent top-down control, exerted by the higher, more evolved forces in nature over the less evolved. In the brain this means a downward control of the mental over the neuronal. However, the principle of emergent downward control (referred to also as 'emergent interaction' or 'emergent determinism') applies to all hierarchic systems in all science.
The new mentalism, combining tenets from previously conflicting views, tends to reconcile polar opposites of the past such as mind and matter, the physical and metaphysical, determinism and free choice, as well as 'is' and 'ought' and fact and value, in a unifying view of mind, brain, and man in nature. The new position appears metaphysical in its recognition of mental events as realities existing in their own form different from neural events, in endowing subjective phenomena with causal influence, and in placing mind in a control role above matter in the brain. At the same time, the interpretation appears to be materialistic in defining mental phenomena as being built of physical elements and being inseparable from the neural substrate. Because it is neither traditionally dualistic nor physicalistic, the new mentalist paradigm is taken to represent a distinct third philosophical position. It is emergentist, functionalist, interactionist, and monistic.
In the new mentalist terms, science no longer postulates that all operations of the brain and behaviour are determined mechanistically or physiochemically as in traditional materialist philosophy. Although the neuro-electrochemical mechanisms sustain and help determine any given course of action, the choice of action is determined largely at higher levels by conscious mental events. Willed choice involves the causal influence of subjective value priorities wherein one's personal wishes, feelings, and other mental factors override the subsidiary forces of the neural substructure. In other words we do what we subjectively wish to do. Free-will decisions are still caused or determined in the new scheme but acquire degrees of freedom and of self-control far above those of classic mechanistic determinism.
The shift of the 1970s in the scientific status and treatment of conscious experience carries far-ranging philosophical and humanistic, as well as scientific, implications. The mind has been restored to the brain of experimental science. The qualitative, colourful, and value-rich world of inner experience, long excluded from the domain of science by behaviourist–materialist doctrine, has been reinstated. The subjective is no longer outside the mainstream of objective science, nor something that will eventually be reducible in principle to neurophysiology. A logical determinist framework is provided for those disciplines that deal directly with subjective experience such as cognitive, clinical, and humanistic psychology. Scientific theory has become squared finally with the impressions of common experience: we do in fact use the mind to initiate and control our physical actions.
(Published 1987)
See also consciousness; mind and body; mind–body problem: philosophical theories.
— Roger Walcott Sperry
- Bibliography
- Armstrong, D. M. (1968). A Materialist Theory of the Mind.
- Sperry, R. W. (1966). 'Mind, brain and humanist values'. Bulletin of Atomic Science, 22.
- — — (1976). 'Changing concepts of consciousness and free will'. Perspectives in Biology and Medicine, 20.
- — — (1983). Science and Moral Priority.
