Emergentism
In philosophy, emergentism is the belief in emergence, particularly as it involves consciousness and the philosophy of mind, and as it contrasts (or not) with reductionism. A property of a system is said to be emergent if it is more than the sum of the properties of the system's parts.
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Emergentism involves a layered view of nature, with the layers arranged in terms of increasing complexity and each corresponding to its own special science. Some philosophers hold that emergent properties causally interact with more fundamental levels, while others maintain that higher-order properties simply supervene over lower levels without direct causal interaction. The latter group therefore holds a stricter definition of emergentism, which can be rigorously stated as follows: a property P of composite object O is emergent if it is metaphysically possible for another object to lack property P even if that object is composed of parts with intrinsic properties identical to those in O and has those parts in an identical configuration. Sometimes emergentist use the example of water having a new property when Hydrogen H and Oxygen O combine to form H2O (water). In this example there "emerges" a new property of a transparent liquid that would not have been predicted by understanding hydrogen and oxygen as a gas, but physicists would claim that they could predict the outcome of these two elements combining so it may not be the best of examples. But such is to be a similar case with physical properties of the brain giving rise to a mental state. Emergentists try to solve the notorious mind-body gap this way. One problem for emergentism is the idea "causal closure" in the world that does not allow for a mind-to-body causation.
John Stuart Mill outlined his version of emergentism in System of Logic (1843). Mill argued that the properties of some physical systems, such as those in which dynamic forces combine to produce simple motions, are subject to a law of nature he called the "Composition of Causes". According to Mill, emergent properties are not subject to this law, but instead amount to more than the sums of the properties of their parts.
Mill believed that various chemical reactions (poorly understood in his time) could provide examples of emergent properties, although some critics believe that modern chemistry has shown that these reactions can be given satisfactory reductionist explanations. This raises the possibility that the emergentist position is more a matter of epistemology than metaphysics.
More recently, however, physicist Erwin Schrodinger in his highly acclaimed work "What is Life?" pointed out that chemical isomers, which are composed of precisely the same individual atoms, though differently arranged, sometimes have similar properties and sometimes have completely different properties. This would seem to suggest that the emergentist position which Schrödinger argues is more a matter of metaphysics than epistemology. Although this might not be true since we can find anything classified as metaphysics explained by the emergentist point of view if we fully understand it. (See, at the isomer link previously cited, the differences between theobromine and theophylline.)
British philosopher C. D. Broad defended a realistic epistemology in The Mind and its Place in Nature (1925) arguing that emergent materialism is the most likely solution to the mind-body problem. Broad's definition of emergence amounted to the claim that mental properties would count as emergent if and only if philosophical zombies were metaphysically possible. Many philosophers take this position to be inconsistent with some formulations of psychophysical supervenience.
Samuel Alexander's views on emergentism, argued in Space, Time, and Deity (1920), were inspired in part by the ideas in psychologist C. Lloyd Morgan's Emergent Evolution. Alexander believed that emergence was fundamentally inexplicable, and that emergentism was simply a "brute empirical fact":
"The higher quality emerges from the lower level of existence and has its roots therein, but it emerges therefrom, and it does not belong to that level, but constitutes its possessor a new order of existent with its special laws of behaviour. The existence of emergent qualities thus described is something to be noted, as some would say, under the compulsion of brute empirical fact, or, as I should prefer to say in less harsh terms, to be accepted with the “natural piety” of the investigator. It admits no explanation." (Space, Time, and Deity)
Despite the causal and explanatory gap between the phenomena on different levels, Alexander held that emergent qualities were not epiphenomenal. His view can perhaps best be described as a form of nonreductive physicalism (NRP) or supervenience theory.
Ludwig von Bertalanffy founded General System Theory (GST), which is a more contemporary approach to emergentism. A popularization of many of the elements of GST may be found in The Web of Life by Fritjof Capra.
- Laughlin, Robert B. A Different Universe. 2005.
- Emergentism in the Stanford Encyclopedia of Philosophy, 2007.
- Emergentism in the Dictionary of Philosophy of Mind, 2007.
