True Complexity and the Associated Ontology

Dear Colleagues,

Science & Ultimate Reality

In recent years much attention has been given to the possibility of unifying the various forces of nature within a quantum mechanical framework and to the formulation of a so-called theory of everything. (See the paper posted in this thread by Lee Smolin.) The quest being carried on by modern physicists to identify the fundamental building blocks of the physical world began with the Greek Atomists. The philosophy that underpins it is reductionism: the conviction that everything in nature may ultimately be understood by reducing it to its elementary components.† But reductionism in general, and the philosophy of particle physicists in particular, has been criticized for committing what Arthur Koestler called the fallacy of nothing-buttery. The problem is that a complete theory of the interactions of particles and forces would tell us little, for example, about the origin of life or the nature of consciousness. It may not even be of value in describing phenomena as basic as fluid turbulence or the properties of bulk matter as mundane as metals.

Many scientists recognize that new phenomena emerge and new principles may be discerned at each level of complexity in physical systems that simply cannot be reduced to the science of lower levels. To take a familiar example, a person may be said to be living even though no atoms of their bodies are living. A reductionist might claim that the phenomenon of being alive is not really a fundamental or ultimately meaningful one, but merely a convenient way of discussing a certain class of unusual and complicated physical systems. But there is an alternative point of view that goes by the name of emergence. An emergenticist would counter the reductionist by saying that it is just as scientifically meaningful to talk about life processes and the laws that describe them, as it is to talk about subatomic particles.

A growing body of expository literature, along with discoveries such as the fractional quantum Hall effect, an electromagnetic phenomenon occurring at extremely low temperatures, has sharpened the focus of debate between reductionism and emergence. It is clear that emergence has relevance wider than physical science.† Other disciplines, particularly psychology, sociology, philosophy and theology, are also vulnerable to reductionism.† If emergent phenomena are taken seriously, then it seems we must take seriously not only life but also consciousness, social behavior, culture, purpose, ethics and religion. For instance, philosophers and theologians debate the vexed issue of whether right and wrong are just human conventions or whether the universe has a moral dimension, perhaps itself an emergent property, but nevertheless real.

George Ellis is a physicist and mathematician at the forefront of the school that takes emergence seriously. A general relativist from the University of Cape Town, he is also co-author (with Nancey Murphy) of On The Moral Nature of the Universe, as well as being co-author (with Stephen Hawking) of The Large Scale Structure of Space-Time. His paper moves the discussion of the symposium beyond physical cosmology into the realm of observers and ontology.

Paul Davies


True Complexity and the Associated Ontology

by George Ellis

Summary:

True complexity, with the emergence of higher levels of order and meaning, occurs in modular hierarchical structures, because these form the only viable ways of building up and utilising real complexity. This is made possible by the existence of atomic structures that allow complex bio-molecules such as RNA, DNA, and proteins with their folding properties and lock-and-key recognition mechanisms, in turn underlying membranes, cells (including neurons), and indeed the entire bodily fabric and nervous system. This is the basis of life [1] and the human brain [2]. The principles of hierarchy and modularity have been investigated usefully in the context of computing [3], and particularly in the discussion of object-oriented programming [4], and it is helpful to see how these principles are embodied in physical and biological structures. They enable simultaneous top-down and bottom-up action, with responses based on stored information and past history. This is the basis of the effectiveness of higher levels of emergent order in terms of enabling higher-level phenomenological regularities of behaviour, described in the language suitable to that level of the hierarchy and underlying effective theories of behaviour at each level.

However there is of necessity a major decentralisation of control from the higher to the lower levels, incorporating many feedback control loops both at each level and between levels, as is required in order to handle requisite variety [5] and the associated information loads [6]. The development of such complexity in living systems requires both a historical Darwinian process of natural selection [1], which develops and stores genetic information characterising the nature of the biological family involved, and a developmental process which uses positional information to control the reading of this genetic information [7] . This sets the context where brain development takes place on the basis of the principles of natural selection, which also apply in utilising genetic information in each individual [8], as is required both because the stored information is far too little to control brain development by itself, and because this allows the brain to optimally adapt to the local environment.

Given this complex structuring, one can ask firstly, what is real, that is, what actually exists, and secondly, what kinds of causality can occur in these structures? Developing previous work by Popper and Eccles [9] and Penrose [10], the view put will be that (i) there is a reality to each separate level of the physical system in this hierarchical structure, (ii) there is a reality to human thoughts and emotion, (iii) there is a reality to the possibility space that determines what is and what is not possible (at the lower levels of the hierarchy, this is characterised by inviolable physical laws, whose ontological status is however unclear), (iv) there is a reality to logical and mathematical structures (which† relate in an unknown way to physical laws). These claims are justified in terms of the effectiveness of each kind of reality in influencing the physical world; however different kinds of reality have different natures. Whether the highest or the lowest level is `ultimate reality' is open to debate, and can lead to metaphysical and theological speculation.

The key point about causality in this context is that simultaneous multiple causality (inter-level and within each level) is always in operation, and any attempt to characterise any partial cause as the whole (as characterised by the phrase 'nothing but') is a fundamentally misleading position (indeed this is the essence of fundamentalism). This is important for example in terms of answering claims that any of evolutionary biology, sociology, psychology, or whatever are able to give *total* explanations of specific properties of the mind. Rather they each provide partial and incomplete explanations.

Finally, fundamental physics underlies and enables this complexity. The basic question for physicists is what are the aspects of fundamental physics that allow and enable this extraordinarily complex hierarchical structure to exist, where the higher levels are quite different than the lower levels [11].† The proposal by† Schweber [12] that the fundamental feature is the renormalization group is inadequate to encapture the whole of this complexity (precisely because fundamentally different kinds of structure and behaviour occur at the different levels). Is it the general nature of quantum theory (e.g. superposition, entanglement, and decoherence), or the specific nature of quantum field theory and/or Yang-Mills gauge theory that is they key, or is it rather the specific potentials and interactions of the standard particle physics model and its associated symmetry groups? To what extent is it dependent on specific constants such as the fine structure constant, or specific particle properties (existence of three families of quarks, electrons, and neutrinos for example)? What feature of physics is the key to existence of truly complex structures? Whatever it is, this must claim to be the `truly fundamental' feature of physics.

References:

1: Neil A Campbell: Biology (Benjamin Cummings, 1990)

2: Alwyn Scott: Stairway to the Mind. (Copernicus - Springer, Berlin: 1995)

3: A S Tannebaum, Structured Computer Organisation (Prentice Hall, Englewood Cliffs, 1990)

4: Grady Booch: Object Oriented Analysis and Design with Applications (Addison Wesley)

5:† W Ross Ashby, An Introduction to Cybernetics

6: Stafford Beer: Brain of the Firm (Wiley, New York. 1981).

7: Lewis Wolpert et al: Principles of Development. (Oxford University Press, Oxford. 1998)

8: Gerald Edelman: Neural Darwinianism: The Theory of Neuronal Group Selection

9: Karl Popper and John C Eccles: The Self and its Brain: An Argument for Interactionism† (Springer, Berlin. 1977)

10:† Roger Penrose: The Large, the Small, and the Human Mind. (Cambridge: Cambridge University Press. 1997)

11: Phil Anderson, `More is Different'. Science 177 (1972), 377

12: Sylvan Schweber: `Physics, Community, and the Crisis in Physical Theory'. Physics Today, November 1993, 34.

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