It is sometimes raised as an objection to science, especially to medicine, that reducing complex issues to simpler terms produces loss of significance of the whole, which like Humpty Dumpty cannot be put together again. This is the 'holistic' criticism of science's reduction of complex issues into simpler parts or concepts. The converse of reduction is that when parts are combined, surprising or mysterious 'emergent' properties may appear — mysterious because reduction-descriptions are inadequate. A familiar example is the creation of water by the combination of the gases oxygen and hydrogen.
Just as the properties of water are different from those of its constituent gases, so, it is sometimes suggested, mind may be similarly emergent upon physical brain structure or activity. Douglas Hofstadter (1979) makes effective use of an analogy — originating from a paper (1911) by William Morton Wheeler — that though ants build their nests they cannot reconstitute them when they have been disturbed and the structure has been destroyed. To conceive that the functioning ants' nest is more than the sum of the ants is helpful when thinking about brain cells (which, also, individually do not understand, or see, etc.), and it is helpful to conceive of the cooperative functioning of brain cells in the process of understanding the mind. Knowledge of individual ants cannot explain nest behaviour and knowledge of individual brain cells cannot explain the mind, even though the nest is no more than ants and the mind depends entirely on brain cells.
Vitalist biologists such as Hans Driesch (1867–1941) have held that the functioning of organisms can never be explained from knowledge, however complete, of their parts because of a vital principle which relates to the whole but not the isolated parts. This doctrine precludes 'reductive' explanations drawn from analyses of the whole into parts that may be separately investigated and described. It implies that the biological and medical sciences are essentially outside the kinds of explanation by reductive analyses that have proved so powerful in the natural sciences. If this is so, biology (and psychology even more so) would seem to be essentially different in kind from physics. Is this holistic view of biology and mind justified? To consider this it is useful to look at simple machines and ask: do we find emergence when parts of a construction set, such as Meccano, are combined to make a simple working model? Putting the parts together in various ways creates very different mechanisms: cars, cranes, clocks, and so on. It is indeed remarkable that the same differently arranged parts may move as a car, lift things as a crane, or keep time as a clock. This can look like emergence beyond explanation — much as for organisms — though here we clearly have simple mechanisms with just a few parts.
The Oxford philosopher Gilbert Ryle tried (1949) to exorcize common concepts of mind that, implicitly or explicitly, dubbed the mind 'the Ghost in the Machine'. But even the simplest of Meccano mechanisms can look quite ghostly! Is this because they have emergent properties? If so, do they still appear ghostly in this way when they are fully understood? Or could it be that we do not yet completely understand simple machines reductively — though we may come to understand machines and organisms so fully that appearance of emergence vanishes, as analysis of the functions of their parts becomes complete?
A machine is assembled from component parts, yet how it functions may be explained by more or less abstract general concepts rather than in terms of its parts. Thus, how a clock keeps time is explained less by describing the parts and their mechanical interactions than from general principles, such as those stating why pendulums swing at a constant rate. We have to look beyond the parts of a mechanism to explain what the parts do. Moreover, there is no simple relation between a machine's structure and its function. A single part, such as the anchor of the clock's escapement, may have several functions, or several parts may combine to provide a single function. Similarly there is no simple correspondence of parts to functions in an organism. (Insights to relations between structures and functions of machines are powerfully expressed by Robert M. Pirsig (1974).)
It is tempting to believe that the high-level properties of organic systems must somehow be present in a rudimentary or dormant form in their parts. But such belief does little to explain how organisms function, and can lead (as with inorganic mechanisms) to notions of molecules, atoms, or even fundamental particles such as electrons having intention, or consciousness. Such notions are without verification, however, and must surely be dismissed (see falsification). We should prefer to say that mind emerges from brain function — if only because there is some hope of finding out what is so special about the brain. But it is hard enough to understand how organisms can be intelligent or conscious, even with all their interacting complexity, and to say that individual brain cells (or, even more extreme, that the individual molecules, atoms, or electrons of which we are composed) have intelligence or consciousness merely pushes the question further beyond answer.
The Cambridge philosopher C. D. Broad argued (1929) that the universe is inherently 'layered', to give emergences with increasing complexity that can never be predicted or explained from any knowledge of lower (generally simpler) 'layers' of reality. On this account, mind may remain beyond understanding despite knowledge of brain or other function — even though mind is causally given by physical functions. Moreover, most neurophysiologists, at least until recently, have held that brain and mind are essentially different — irreducibly two kinds of things — the causal connection (denied by Leibniz) notwithstanding. (See also mind and body; mind–body problem: philosophical theories.)
This duality may be criticized on the principle of Occam's razor, as postulating entities unnecessarily, though one might follow the physiologist Sir Charles Sherrington's (1906, 1940) opinion: 'That our being should consist of two fundamental elements offers, I suppose, no greater inherent improbability than that it should rest on one only.' By contrast the neurologist Wilder Penfield (1975) came to the view that the mind is the emergent characteristic of brain function and depends on physical processes of the brain. This is probably the prevailing view, though Broad's 'layers', limiting reductionist explanations, are largely ignored or denied.
Whether these dualist and emergent accounts of mind are so different, and just what each implies, depends on extremely difficult issues of what should be accepted as causal and what as emergent, and how emergence may be seen in causal terms. The answer seems to be that causal explanations require general concepts, or 'meta'-accounts, and that these can remove the mysteries of emergence, though not simply by 'reduction' to the parts. But so far an adequate meta-account for linking brain function to mind is lacking.
These issues have significance not only in science but also for anyone who wishes or needs to understand or apply scientific concepts, for the language, ideas, and aims of scientists differ according to the level of reduction in which they think and work. Thus a fundamental particle physicist or a cell biologist may find the concepts and aims of the neurologist alien and hard to appreciate — while the cognitive psychologist might as well be living in a different universe. And yet such universes of discourse have to be bridged for adequate understanding, and in many cases for effective research and action. Art and science have been described as 'two cultures'; but science is also divided within itself, with prestige accorded to the 'deeper', more 'fundamental' concepts — even though they may be inadequate to explain the way things are higher up the tree. And it is not clear even that this tree is rooted in the 'fundamental' sciences — for its 'levels' of explanation depend on the observations and intelligence of our minds at the treetop.
(Published 1987)
— Richard L. Gregory
- Bibliography
- Broad, C. D. (1929). The Mind and its Place in Nature.
- Hofstadter, D. R. (1979). Godel, Escher, Bach: An Eternal Golden Braid.
- Morgan, C. Lloyd (1923). Emergent Evolution.
- Penfield, W. (1975). The Mystery of the Mind.
- Pirsig, R. M. (1974). Zen and the Art of Motorcycle Maintenance: An Enquiry into Values.
- Ryle, G. (1949). The Concept of Mind.
- Sherrington, C. S. (1906). The Integrative Action of the Nervous System.
- — — (1940). Man on his Nature.
- Wheeler, W. M. (1911). 'The ant-colony as an organism'. Journal of Morphology, 22/2.
