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21 March 1998
Professor Mark Birkinshaw, William P. Coldrick Professor of Cosmology and Astrophysics, University of Bristol
Professor Birkinshaw started the day with a lucid account of the present state of attempts to produce a unified theory to explain the physical forces, and how this applies to the history of the Universe.
Of the four forces, three can be successfully combined in an acceptable theory called the Standard Model. This encompasses the strong nuclear force, the electromagnetic force and the weak force. All of these have their associated particles which act as carriers of the force and are known respectively as the gluon, photon and intermediate vector boson. Above a temperature of about 1027 K, all three forces behave in a similar manner.
The fourth force is gravity which has so far resisted efforts that are universally accepted to combine it with the other three. The principal difficulty is that gravity is adequately described by general relativity, which is a geometric theory, but the others are described by quantum theories.
The effects of gravity were illuminated by pictures using the largest known telescope in the universe; fortune has arranged that a galaxy at a distance of 750 million light years can act as a gravitational lens to ‘view’ another one 3000 million light years away! The latter has a distinctly blue tinge to it as it contained so many young stars when the light started its journey.
If we turn the clock back to 15 billion years ago, then we come to a time when the temperature was about 3000 K and the ionised plasma would have cooled to gas, which allows photons to pass unhindered. The microwave background radiation which can be detected in whatever direction we look dates back to this period. Recently variations in the strength and constitution of this radiation have been found that confirm that the Earth does indeed rotate about the Sun, and even measures the Sun‘s speed through space.
Further still back in time, the temperature would have been 1010 K and the electromagnetic and weak forces combined. The full Standard Model applies at a time when the temperature was even higher, within 10-26 seconds of the Big Bang. Before that we have only speculative models and before 1043 seconds they are ultra-speculative, requiring quantum gravity. It is perhaps no wonder that the most fashionable of the unified theories is known as M-Theory, where M may stand for Magic.
Professor C.J.S.Clarke Dean of Faculty of Mathematics, University of Southampton.
Professor Clarke emphasised that the notion of a Theory of Everything (TOE) resulting from a study of particle physics is not only wrong but dangerously wrong. There is need to assess the priorities and assumptions behind the word ‘everything’. In reality, this concept is a restrictive one, excluding many important aspects of human life.
TOE, emphasises the purely ‘intellectual’ to the exclusion of the ‘human’ aspects of mankind. It assumes that the quest for a TOE will have an end.
Evidence shows this not to be the case. Physics does not progress by increased unification, but at the price of greater complexity, and the uncovering of yet more problems. There is no indication that fundamental physics at the quantum level will have anything further to say about biology, psychology or consciousness. Fundamental physics should be studied in the noble spirit of human curiosity rather than as a means of explaining everything.
Current evidence suggests that many properties of our conscious world cannot ,in principle, be tackled by a science that builds from the bottom up. Knowledge of the brain at the neurone - level tells us nothing about what it feels like. Conventional reductionism fails to say anything about subjective experiences. The concept of TOE is a dangerous one. Firstly, it tends to focus on aspects of the universe that are totally independent of human action. For the particle physicist the universe is a body of eternal laws, which we need to learn and read. Ultimately we are reading something that is absolute and unchanging.
Secondly, it implies that TOE can be attained purely by intellectual means. Thirdly, the intellectual understanding of absolute laws would confer absolute control. Life would have reached paradise.
The real world, our world, in contrast to the physicists’ world of particles, laws and forces, is a world of complex and rich qualities. We know it not just through our intellect, but through our bodies. It is a world of delight and pain - the delight of intellect and the body, the pain of frustration and death. It is a world that we are actively creating and shaping.
Professor Clarke then discussed the reasons for the generally accepted importance attached to physics, and the consequences of this in terms of human values. In contrast to areas like psychology, a study of physics delivers reproducible results and certainty. The quest for certainty require us to focus on the material - on physics. Accordingly, we tend to build a technology based on this materialistic and reductionist science. This is where we look in order to exercise control. We may ask what effect this has on the psyche of humanity. The physical is valued not for itself but for its utility. The spiritual is totally ignored because it does not fit in with the reductionist world. Consequently we create a value system that denies much of what makes us human. To succeed, we are persuaded to master the technology, learn the language of science, ignore our emotions and repress our artistic creativity.
We are gripped into a vicious circle. The more we struggle to incorporate ourselves into the fantasy of intellectual control and certainty, the more the exclusion of everything except the material leads to alienation and insecurity. The more insecure we feel, the more we struggle to reach the certainty of a complete Theory of Everything.
Professor John Dupre, Profesor of Philosophy, Birkbeck College, University of London
Prof. Dupre began by describing the historical background. The Theory of Everything (TOE) started with the attempt. so far unsuccessful, to develop a unified theory of fundamental forces in physics, as described by Prof. Birkinshaw in the previous talk. This concept was then enlarged, with an attempt to include all aspects of science in an Encyclopaedia of Unified Science, by the logical positivists in the period of, roughly, 1930 - 1960.
Unity of Science, or more precisely, the unity of the methodology of science, was considered as the working hypothesis underpinning the entire effort. The point of departure was to arrange science hierarchically, with the fundamental physical theory at the base, then molecular chemistry, molecular biology, and all the way to social science. With the hierarchy in place, the theories at the higher level were to be explained by those below hence reductionism, which was considered as another basic hypothesis. But the system, to be workable, needs bridge laws to connect the theories at one level with those at another. The unavailability of bridge laws, the fact that there is no practical way to reductionism, has made the programme obsolete. The unification of the fundamental laws of physics remains, however, a possibility actively pursued by quantum cosmologists in their search for a theory combining gravity with quantum mechanics. In a considerably restricted way that is the current meaning of the "Theory of Everything°.
Dr Alan Rayner, Reader in the School of Biology & Biochemistry, University of Bath
With the help of some of his own paintings, Dr Rayner took the gathering into the world of biology and the dynamics of living things, their organization, free-ranging yet constrained, competitive yet co-operative, and responding to changing fortunes.
He advocated seeing life in the round as opposed to the usual discretist approach concerned with demarcations between the inside and outside of everything to enable one to be sure of being definite and able to calculate. Discretism neglects the facts of passing time.
Life forms are leaky containers, separate from yet in communication with their environment. Boundaries of life forms are dynamic interfaces enabling them to feed the organism with the energy necessary for living. As an example of his thesis, Dr Rayner took the inkcap fungus, showing its mycelium, its production department as it were, grown in a grid whose cells were either rich in or lacking nutrients, to demonstrate how the organism adapted to conditions of growth and so managed its needs for energy. The mycelium made a beautiful pattern in itself.
Animals should also be seen as trajectories moving through space and time; he showed the patterns made by driver ants and wildebeeste migrating and following paths of least resistance. Like animals, plants and fungi compete for territory. Fungi of the same species compete or collaborate according to the compatibility of their genes; they seem to reflect the mergers, takeovers and the like in our own society. His observations led on to the idea of contextual dynamics, processes taking place across contextual boundaries to drive the transfer of energy and biological development. These processes, in his view, therefore drove evolution.
Life forms bridge gaps around them to deal with scarcity of nutrients according to evident principles of self organization. Randomness in behaviour is seen differently according to whether one's viewpoint is systemic or one sees it as a consequence of the action of boundary dynamics. Organisms respond to changing conditions by developing their boundaries to increase surfaces to absorb available energy, or, in face of scarcity, by withering or by developing into more closed conservative forms to survive.
Questions ranged from possible connections between the life and death of stars and the behaviour of biological boundaries, to evidence of consciousness in such life forms and how their past experiences of conditions plainly influenced their present actions. There was some disagreement as to whether his biological models could be applied to human society and economics.
Dr Carolyn Wilde, Dept. of Continuing Education, University of Bristol
What is the scope of everything in our question? It can only be that which is susceptible to theoretical explanation, which may not, of course, be everything. Although there are pertinent things to be gained from noting that the word ‘theory’ has its roots in the Greek word which is cognate with ‘theatre’ (beholding something separate) and ‘theology’ (the source of authority), in our more immediate context a theory is an attempt to explain or understand some phenomena in terms which can be generalised over relevantly similar phenomena.
Two things are directly relevant in this account of theory. First, as with any effective explanation, there must be some distinction between the description and the explanation. But this simple condition already brings with it difficulties for the idea of a theory of everything. For the terms in which we describe something may be fundamentally different from those in which we give the explanation - the terms in which physics or chemistry explains the world we ordinarily experience for example, or the experience, are of a radically different order from how we describe what we see and feel. Thus, already, we face the problem of the relationship between experience - how we are
conscious of ourselves and the environment we are in - and theory, which essentially involves processes of abstraction and calculation which in principle can be repeated by anyone with the appropriate expertise. This is one familiar version of the perennial philosophical problem of the relationship between the knowing subject (the conscious human being) and the object of knowledge, which goes by many names, the most general and problematic one of which is, perhaps, reality. In the context of modern science, however, we use the term nature for that realm which is the object of enquiry. But the concept of nature is itself regulated through the very methods recognised as constituting proper objective enquiry. Thus the distinction between the natural and the supernatural is itself contested within the methods of the natural sciences and the scope of any enquiries defined by those methods.
And secondly, the minimal account of theory with which I began obviously raises questions about what counts as valid generalisation and what constitutes relevantly similar phenomena, which, in turn, involves principles of classification. But how we classify things typically depends on our interests. Science in the Western tradition begins with the attempt to define what basic sorts of things there are independently of any specific interest and to give the most economic account of the laws or principles governing their changes and interactions.
At the beginning of the modern period the philosopher Descartes attempted to put the New Sciences on philosophically secure foundations. Two things about his project are especially relevant to our question here. First, he began with the method of scepticism: to doubt all which could not be given some logically secure foundation. And he described the system of knowledge which he thought could be derived from his indubitable foundations by means of an architectural metaphor, as an edifice or house. In this house, the various rooms would be interconnected and each storey would rest on the one beneath. Although when Descartes was writing there were no sciences of the human subject, on his model, sociology and psychology would in time take their place on the higher floors.
Although Descartes’ arguments were challenged from the very beginning, the progressive idea of knowledge which they implied had a deep and pervasive influence on both the professional and popular image of the nature and scope of the natural sciences. In principle the edifice could be completed. But it was also a crucial part of Descartes’ argument that the mind that thinks or constructs this edifice of knowledge must be of an essentially different stuff from the material reality into which it enquires. Thus there was from the start of Descartes’ project the intractable problem of the place of the knowing subject in this great building. In this half of the Twentieth Century different attempts are made to bring the human mind and its workings within the scope of scientific theory, not merely in terms of the laws governing its effects in human behaviour, but more substantially in terms of the electrical and bio-chemical workings of the physical organism centred in the human brain.
Yet two things remain problematic. Since it cannot be a condition of knowledge that we are infallible about everything, what is to count as the foundation for any unified theory must in principle remain revisable. And since the way in which the conscious person experiences and represents the objects of enquiry cannot be reduced without residue to the physical processes which are in some way necessary for that experience, the reflexive requirements of representation obstruct the very idea of a theory which will encompass everything, including its own theoretical construction. Perhaps most significantly, the values which inform the sense people make of their lives are similarly not reducible to any naturalistic explanation without loss of a complexity which is of a different order from that involved within biodeterminist explanation.
These considerations have their counterparts within physics itself and the place of the observer within scientific enquiry. They also have had a somewhat baneful influence on that sort of philosophical thinking which is ‘Relativism’. But in acknowledging that the results of an enquiry are inevitably presented in terms of the interests and method of that enquiry (and how else could it be?), it neither follows that the constraints on truth within that enquiry are either arbitrary or merely conventional nor that all sorts of enquiry are in some vague and general way equally subjective. The fact that there cannot be a systematic theory of everything that can be theorised does not in itself challenge the possibility of objectivity and truth in our enquiries into things beyond our immediate human concerns.