Meaning and Structure in Biology and Physics: Some Outstanding Questions
F. David Peat
To take a one week course with David Peat
Talks given at Temple University Conference on Basic Issues in the Overlap and Union of Quantum Theory, Biology and the Philosophy of Cognition, Bermuda 15-21 April, 1988.
A text only version of this essay is available to download.
In a meeting of this nature, in which physicists and biologists come together to discuss fundamental concepts, and the ways in which the ideas of one discipline could act to transform the other, it is important to foster an open and creative dialogue. But it is sometimes difficult, for people of separate disciplines and training, and who have different scientific goals and overviews, to find a common ground. The purpose of this talk is to explore a number of frontier areas in which new radically approaches may be needed and in which physicists and biologists could stimulate each other's approaches. This talk also draws attention to potential areas of confusion and discord which may be blocking a more creative advance.
It was Neils Bohr who emphasized what he called complementarity in science. While this idea was first introduced with specific reference to the quantum theory, Bohr really felt that the idea of complementary had a universal application and extended to all forms of inquiry and knowledge. As Bohr put it, knowledge and the means of inquiry are inseparable. There is an essential wholeness to our investigations of nature, for the way we investigate things cannot be separated from the results we obtain. The genesis of this idea lies in the quantum theory where experimental results are dominated by Heisenberg's uncertainty principle and by the wave/particle duality. Ask a particular experimental question and nature answers in terms of waves, pose the question in another way and the result is in terms of particles. In the world-view of classical mechanics the concept of wave and particle are mutually exclusive and this too is the essence of Bohr's proposal--that the results of experiments on the quantum world are complementary or mutually exclusive.
Bohr believed that complementarity had a universal application and, in particular, it applied to biology and psychology. No matter if the means of inquiry are experimental, theoretical, philosophical or linguistic they are always inseparable from the nature of the answers we obtain. Investigate any system of sufficient subtlety by different routes and one will obtain complementary answers.
Complementary viewpoints will, therefore, be particularly apparent when biologists and theoretical physicists meet together, and if scientists are to have a deep influence on each others ideas then they must be especially sensitive to the complementary nature of their approaches and have the necessary intensity to engage in a truly creative dialogue together.
Another feature of these complementary approaches is that ideas and concepts, which on the surface may sound very similar, are associated with different meanings and are used in quite different contexts by physicists and biologists. The result can be the sort of linguistic confusion that the philosopher Wittgenstein spoke about. There is a danger of engaging in long and fruitless debates of great intensity, in which the parties emerge confused and frustrated because their views do not seem to have been taken seriously.
As Wittgenstein pointed out, words are like tools, they have many different functions. What is appropriate in one context may be inappropriate in another, and there is always the problem of confusing the functions of words and using their different meanings in insensitive ways. Indeed, cognitive psychologists have pointed to the way in which the human mind, when faced with an area of confusion, tries to suppress the perception of this confusion by keeping on working. It does this by, for example, "patching over" an area of ignorance by means of a series of arbitrary rules. In fact stopping all activity and confronting the ignorance or confusion would generate great anxiety, and the mind, therefore, prefers to continue its activity--even when this whole process is no longer fruitful. Once again physicists and biologists must be especially sensitive, in their dialogues together, that they do not become trapped in a maze of their own construction.
How then will it be possible for new concepts, ideas and approaches to evolve through this overlap and union of quantum theory, biology and the philosophy of cognition? In the case of the present meeting, the creativity of the participants presents no problem. What, therefore, seems appropriate is to address those areas of confusion in which notions are being used, by both disciplines in subtly different ways, to unfold the meaning of these complementary viewpoints and to discover those areas in which old and new ideas do not cohere.
In what follows I shall briefly sketch out a number of areas which are of particular interest to me, areas in which particularly difficult questions are posed and in which a new creative approach is needed. It is possible that deeper insights will be gained in these fields, not so much through new ideas, but through a process of clarification and dialogue. The areas I will talk about embrace physics, biology, artificial intelligence and the cognitive sciences and involve questions about order and chaos, language, meaning, mind and information, emergence, novelty and creativity.
Symmetry, Structure and Information
Symmetry theory has proved the keystone of much of the important work in elementary particle physics over the past decades. It is also an important concept in biology, particularly for morphogenesis. What may prove interesting is the different way this basic concept is used in both fields.
It was the 19th century biologist and geneticist, and father of Gregory Bateson, William Bateson, who made an identification of symmetry with information, or rather with the loss of information. William Bateson had noticed that whenever a mutation, involving an extra hand or foot, occurs, it does so in a symmetric way. Mutation involving a right arm, for example, does not produce an additional, second, right hand but, rather a left and a right hand. At first sight this looked as if nature was going to some trouble in order to create its mutation--not content with producing a second hand on a limb it took the trouble to produce a hand of the opposite parity!
But, as Bateson pointed out, what is really happening is a loss of information. When genetic information is destroyed through mutation then nature is always forced into a more symmetrical form. Two hands that are mirror images of each other require less information to define them, that the symmetry-broken case of two right hands on the one limb!
Bateson therefore equated information with symmetry, structure and information:
An increase of symmetry = Loss of genetic information.
At first sight, this is a curious identity of two different concepts, symmetry and information. And, by implication, the more information that is being expressed or unfolded by a organism the more will its initial symmetry will be broken and the more complex will be its structure. The idea of information, in an active form, was, in fact, being introduced into biology.
In the developing organism the initially spherically symmetric cell divides in two, then four and so on. At each stage symmetry breaking occurs, with the more symmetric state giving way to one of lower symmetry and greater structure. It is therefore possible to speak of the symmetry broken states, with their more detailed structure as having greater explicate information. However, the actual process of differentiation itself is driven by active, implicate information within the cell itself--the genetic code. In other words the explicate expression of this implicate information is brought about through a progressive series of symmetry breaking steps. The developing organism represents a transformation between an implicate to an explicate order of information. And, where a loss of this implicate information occurs, as with a mutation, symmetries are restored.
Today we find information being used in a number of different ways and, in particular, the term "information" surfaced again and again in this conference within a variety of different contexts, from the structure of mind to the very subtle active information that, according to David Bohm, directs processes at a quantum level, it was also used in such fields as the language of the genetic code and communication between cells.
Bateson's term information--which his son Gregory Bateson defined as "the difference that makes a difference"--is given in the context of symmetry and structure. It is interesting, therefore, that a connection between symmetry and structure has also emerged within modern physics. A dominant idea in physics today is that structures increase in complexity through a process of what is called symmetry breaking. According to this argument nature's laws are written in the most general and most symmetrical forms However, the actual physical solutions involved do not always exhibit such symmetry but have the effect of "breaking" it. Such symmetry breaking is always associated with the appearance of new structure within the system, such as excitations or new elementary particles. These excitations could be thought of as containing a "memory" or shadow of the original symmetry. Hence, the breaking of a basic symmetry has the effect of increasing the structural complexity of a system. The equation of modern physics is
Symmetry Breaking = Increasing structure and complexity
To take an example, the law governing magnetism is symmetric in space, for it does not pick out a preferred direction. However a actual ferromagnetic possesses a North pole and clearly breaks this symmetry. Accompanying this symmetry breaking is the appearance of new excitations called spin waves. The lattice of a metal also breaks the basic translation symmetry of space, by virtue of its internal structure which has a lower symmetry than that of the most general translations and rotations in space. Again, the shadow of this original symmetry is now present within the phonons or thermal vibrations of the lattice.
Symmetry breaking has become of key importance in elementary particle physics where the forces of nature are initially assumed to be unified, at the Big Bang creation of the universe, within a more symmetric, universal law which is then progressively broken to reveal four separate forces. In addition, the elementary particles originally appear in a highly symmetrical pattern, having equal (zero) masses which are later differentiated though a process of symmetry breaking.
The idea of symmetry breaking has reached its most extreme form in modern superstring theory in which the origin of universe is conceived in a highly symmetrical form. All the physics we observe around us, the forces, masses and properties of the elementary particles, become an extraordinarily tiny, hyperfine correction produced by symmetry breaking. Edward Witten has taken this even further. Space-time itself with its particular choice of metric is the symmetry-broken form of an even more symmetric theory in which no particular space-time exists!
Modern physics has, therefore, come down firmly on the side of laws which must have the greatest symmetry and generality, indeed this is often taken as an example of Occam's razor. Structure emerges through a series of fortuitous symmetry breakings which go to build up the detail of the universe. It is almost as if, in the desire to obtain laws of increasing generality, science was pushing all the really interesting physics out of the window into the arena of symmetry breaking! According to this approach the universe is created with the minimum possible structure (or to use another concept, its implicate information vanishes) and evolves through a fortuitous series of symmetry breakings.
This is the direct opposite of the biological situation in which the growth of the cell is associated with a breaking of its initial symmetry and an increase of structure and complexity through the transformation of implicate information into an explicate structure. In this case the driving force of structure and symmetry breaking is not fortuitous but is the activity of the information enfolded within the DNA. (And here I do not wish to rule out the possibility that there may be additional sources of information.) Biologists, however, do not appear to have problems with Occam's razor!
But could it be possible that symmetry breaking within physics could also be the result of some underlying implicate "information"? Could it be that the most fundamental laws of physics may, in fact, be formulated in more subtle ways?. Roger Penrose, for example, has investigated one case in which the underlying laws of nature may not be in the most symmetric form. Penrose developed an alternative theoretical language (twistors) for investigating the properties of massless quantum fields associated with the graviton, neutrino and photon. His analysis shows than, contrary to the usual symmetry breaking approach, the right and left handed forms of these particles do not emerge out of a single symmetrical laws. Rather their handidness is built right into the underlying laws! According to Penrose the laws of physics may contain the basic asymmetries of the world we live it!
Another approach is to consider nature as arising, not out of some highly symmetric form, but from an exceptionally complex underlying order in which the symmetries themselves emerge as averaging procedures. In such a case physics would be brought more in line with biology in which symmetry breaking and the emergence of structure is an expression of the underlying generative, or implicate, information, while symmetry represents a loss or averaging of such information. This is certainly an area which warrants some serious investigation.
Another field that needs clarification, and would benefit from dialogue between biologists physicists and, incidentally, linguists, is this whole notion of information and the related notion of order. Information, as defined by Shannon and Weaver is, for example, inadequate for any serious discussion of linguistics--in which information plays a more active role in which the participants themselves act to generate meaning. In addition the notion of a subtle, or active form of information has been introduced by David Bohm. Discussion of this whole topic would be of importance in the fields of artificial intelligence, biology, cognitive science, physics and linguistics.
The Infinitely Subtle Order
Theoretical physics currently holds that nature can be described by a very few simple context-independent laws and that structural complexity emerges through symmetry breaking. A totally different way of looking at this would be to suggest that the symmetries we happen to see may be only approximately true, or the result of some averaging effect, and that the underlying laws themselves are far more complex and subtle.
David Bohm, for example, has suggested that these deeper levels are extremely subtle and act to "inform" or give form to the more gross levels--just as the subtle signal from a TV station gives form to the more gross energy in the TV set. One could also mention the importance of form in the wave function of quantum theory, indeed a particular antisymmetric form is responsible for the correlations dealt with in Bell's Theorem. Again form or information appears as an underlying theme.
In particular, information originating at a subtle level of matter acts at a more "gross" level. An example of this would be the unfolding of information, implicit within the genetic code, at the level of the cell. And here I am suggesting something more active and generative than is usually meant by "the genetic code". But there is also the possibility of other levels of increasing subtlety in nature, indeed, levels that merge into what we call mind. Or rather, that the material and the mental may be two particular orders of some more fundamental process.
Related to this whole question is the need for some new definition of what we mean by order. Physics and mathematics have had great success in describing relatively simple, mechanical forms of order, as well as what is normally called chance or randomness. What is lacking is a formal language for dealing with orders involving very high degrees of subtlety, such as the order of language, music, a conversation, a painting, an emerging life form, the weather, a non-linear amplifier, a river, sub atomic matter, a cell.
Determinism and Chance
The concepts of determinism and chance are also areas in which radical new insights may be possible, and in which both biology and physics can make contributions. These notions are significant, no only for pure science but because of the deep influence they have upon our world-view and our metaphysics. The notions of progress, control, goals, planning, directions, predictability and problem solving are based on informal ideas about determinism and chance which were derived from restrictive, closed, mechanical models. Today, however, the study of non-linear and chaotic systems have made a rich new set of metaphors available to us.
Western society is much concerned with the paradigms of progress, control, manipulation and with the notion that all problems can be defined and isolated so that solutions or cures can be found and corrections applied. This attitude of mind is bound up with a fragmentary approach in which systems can be divided and boundaries applied. But today we know that there exist non-linear, and quantum, systems in which the effects of boundary conditions can be extraordinarily subtle; systems that are infinitely sensitive to perturbations, and for which prediction is not theoretically possible. Control of such systems may be out of the question for any attempt at intervention will produce unexpected results.
Systems like these represent a rich new field for exploration with their infinite detail, regions of self similarity, bifurcation points, and areas of intermittency. They call into question the whole notion of boundaries, predictability, chance, determinism versus indeterminism, etc., and open the possibility for behavior that depend on contexts. This suggests that radical new changes in policy making and in the structure of human organizations is called for, as well as the need to question the supreme value which society has placed upon progress.
We have seen that the genetic code could be thought of as an implicate order of information which unfolds into the explicate structure of a living system. But what exactly is this implicate level? Is it sufficient to describe it in terms of the current paradigms of chemistry and biology? Is the genetic code simply a static, "ultimate level" for biology, or is it possible to regard it as the source of some context-dependent, generative order? Can the genetic code be explained exclusively in terms of a particular molecular geometry or does it have a more subtle origin?
I would like to suggest one way of explaining these questions. A code is something which operates within the context of a language- after all it cannot be strictly called a code in the absence of language. But what language is the genetic code a part of? What language is spoken by the cell? (See A.J. Ford and D. Peat, Foundations of Physics, December, 1988.)
Suppose we were to take this suggestion literally, that there does indeed exist a language of the cell, and of the whole organism. This would mean that, at some subtle level, a cellular language exists with all the richness , flexibility, syntax and semantics, poetry and ambiguity, ability to analyze and describe itself, to pose and get out of self-referential paradoxes as any other language. Such a language must be able to transcend logical types, to joke, and create new metaphors. This would be the language through which the intelligence of the cell chooses to speak.
When a child first learns to speak, everything it says is new, the child utters sentences it has never heard before. Is a similar creativity possible in biological systems. Does the cell possess poetry? And, when we speak of communication within biological systems, should this be taken to mean a simple passive exchange of information--in the sense of Shannon and Weaver--or could it imply the generation and sharing of meaning, a true communion? Clearly the notion of a shared meaning would be of great relevance to the health of the organism and the operation of the immune system.
These are highly speculative questions which bring together, yet again, such notions as symmetry, information, generative and implicate order, subtle and gross orders of matter, along with the idea of the meaning and health of the whole organism.
The order of time is tied up with the orders of progress, change, values in society etc. How are we to understand time? Are we trapped by time or is there something faster and more subtle than time? Is there something that transcends time, as we understand it in the evolutional and mechanical sense? And what is the meaning of time to the embryo in which all space and all time is rich in potential? Is there an order that lies outside of time? And how is consciousness tied to time?
Artificial Intelligence has done great service in sharpening and bringing into focus many of the traditional questions of cognitive psychology. We have learned, for example, that many of the tasks which give us a headache, like chess and arithmetic, can be carried out by a computer. While things we find easy, like language, catching a ball or recognizing a face, prove to be enormously difficult to the computer. So the whole notion of what we take to be intelligent behaviour is beginning to change.
I believe that there is a whole tangle of questions that are grouped around AI, cognitive science, the neurosciences, psychology, etc., that may prove enormously difficult to resolve. In addition, it is important to go into the whole question of why computer "intelligence" is limited, and how it differs from the creative, non-lagortihmic possibilities inherent within the human brain.
For example, the following questions are all very different but tend to be confused together:
Can machines become intelligent?
Could machines have free will, goals, volition, choice, emotions etc.
Could machines effectively simulate human behavior?
Could machines solve the sorts of problems that humans solve and in this way carry out effective action (but maybe using different tactics)?
Can all human behavior be described through collections of rules and algorithms?
Is machine and human intelligence a software problem or a hardware problem?
Is mind determinate? Can it be explained in terms of brain?
Can the brain be described using the known physical laws?
Is there some emergent level associate with brain?
Must computers always operate according to fixed algorithms, rules or programs. Does the brain operate any differently? Or can we give a meaning to an unconditioned process? How else can we explain creativity?) In other words is there something within the mind that is not fixed, and is free?
Can all of physics be described in terms of algorithmic physics, or are there more subtle non-algorithmic levels?
Did life and the brain specifically evolve to exploit that curious boundary that lies between the quantum mechanical and the classical worlds?
Quantum Mechanics and Consciousness
There are some who believe that quantum theory may play a special role in the behavior of the brain. It seems to me that many interesting possibilities may lie on the borderline between the quantum and the classical. The human senses, for example, operate right down to the quantum domain. The brain clearly involves quantum processes and the synaptic level, and there may also co-operative, soliton-like behavior along nerve pathways, ( a phenomenon which also occurs at the classical level). Molecular recognition of enzymes and involving the immune system may also require some sort of quantum mechanical explanation.
What is of particular interest is those systems which exploit both "classical" and " quantum" behavior. Certain biological molecules may bridge this gap by having stable "classical" geometrical structures which can still accommodate quantum excitations. In addition there may be dynamical processes of the same dual nature. Is there, therefore, a level lying between the classical and in which new and more subtle forms of behavior could emerge?
Take the idea that the form of the wave function is significant in quantum theory. This certainly accounts for the correlated results associated with Bell's theorem. But could a particular form be responsible for inducing subtle correlations across the brain? In this way information operating at a very subtle sub-quantum level could then express itself through macroscopic correlations within a living brain. (See Peat--(to appear in book on Bell's Theorem)
Another idea- that biological molecules have evolved to exploit a particular scale at which a dual quantum/classical behavior exists? In addition biological systems may depend on various collective states for their operation and recognition processes. Such properties may depend upon a rich structuring of Hilbert space. (For such ideas, on classical/quantum behaviour, feedback and molecular recognition see Peat , Foundations of Physics, December, 1988)
Language and Vision
A key problem in cognitive science, Artificial Intelligence and the neuroscience is how we actually "see" a world out there. While much effort has been made into describing the early stages of vision in terms of algorithms and "hard wired" processing within the brain, this much deeper question remains essentially untouched. How is it that we can recognize a face ten or twenty years later, within different expressions and illuminations? What "language" does vision use? What, indeed, does it mean to "see" the external world? How does the act of vision depend on the whole meaning we give to a scene? How does vision relate to language? (As a clue I would suggest that one of the deepest ways of looking at human vision may be by considering how, in different ages, great painters have come to solve the problems of representing the visual world.)
Vision is essentially creative in nature, it is a paradigm for the other human functions in that it is intentional and creates the world. Vision is also tied up with the whole question of language and with the notion of the "meaning" of a system.
Health, Wholeness, Meaning
Clearly health is tied up with the notion of wholeness. The immune system is indivisibly linked to the meaning of the body, the live of the individual and to the values in society. Health is to do with a field of wholeness. It lies in the creativity of the organism and, clearly, when this is blocked sickness, rigidity and a mechanical response invades the individual and the whole of society.
Again and again, I feel that the same questions keep cropping up in this talk, each time returning in a new context. They are questions about language, order, meaning, communication, generative order, active information and I hope that in our discourses together we can give them a fresh meaning.
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