Towards an evolutionary thermodynamics of ecosystems

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1 Towards an evolutionary thermodynamics of ecosystems E. Tiezzi & N. Marchettini Department of Chemical and Biosystems Sciences, University ofsiena, Italy. Abstract The epistemological and thermodynamic bases to proceed towards an evolutionary physics are presented, having in mind the new theories of the Bruxelles's school (Ilya Prigogine). Namely the relationship between evolutionary thermodynamics and complexity of ecosystems has been taken into account, focusing the attention on the role of time, emergence and creation of events. Energy vs. entropy is discussed in more details, in terms of dissipative structures and Prigogine's thermodynamics. 1 Introduction Biological activity is a planetary property, a continuous interaction of atmospheres, oceans, plants, animals, microorganisms, molecules, electrons, energies and matter, all part of a global whole. The role of each of these components is essential for the maintenance of life. The relations and activities of the global biogeochemical system are life. The aim of science is to maintain these relations and characteristics, to live in harmony with nature, not to conquer it. This type of science comprehends complexity and uncertainty, it moves away from a deterministic-mechanistic view of the world in favour of a holistic and evolutionary view. Man can relate to the environment in many and varying ways in space and time. Although man has always manipulated and exploited the environment for his own purposes and well-being, in the last hundred years the acceleration of scientific and technological progress has aggravated and revealed the consequences of this exploitation. Recently, the global consequences have

changed our perception of the problem in an increasingly radical and widespread manner. The main aspects of the problem can be summarised as follows.

2 changed our perception of the problem in an increasingly radical and widespread manner. The main aspects of the problem can be summarised as follows. It is worth remembering that the irreversibility of the changes occurring and uncertainty about the entity and repercussions are the most alarming elements: - depletion of resources - local pollution (air, water and soil) and degradation of the biosphere (greenhouse effect and ozone hole) - erosion of environmental resilience - loss of biodiversity. As pointed by out Stephan Harding [l] "conventional science has provided many benefits, but it has also unintentionally contributed to the current ecological and social crises, characterised by the mass extinction of species, climate change and social breakdown. We have inherited conventional science from the scientific revolution of the 17th century. Bacon suggested that we must torture nature's secrets from her in order to gain dominion over nature for the benefit of humanity, that we must gain knowledge for control of nature. Galileo stressed the primacy of the quantifiable, affirming that subjective experience can tell us nothing useful about the world. Descartes asserted that the universe, including the human body, is a vast, inert machine, and that the screams of vivisected animals were to be disregarded, since for him they were no more than the creakings of mere mechanisms. Newton's equations appeared to verify this mechanistic world-view, as with their use scientists could accurately predict the movements of projectiles and celestial bodies. Two centuries arer Galileo, Laplace went so far as to comment that if it were possible to quantify everything in the Universe at a given moment, then its entire future could be accurately predicted using this new scientific method, including all subsequent human behaviour. This perspective strengthened the belief that the world is machine, having value only when converted by science and technology into objects useful for human purposes. Far from being a machine valued only according to utilitarian criteria, the world was experienced as a living being in its own right, infused with intrinsic value. The followers of Descartes and Laplace believed that science could provide total certainty and absolute predictability, but conventional science has recently been forced to admit that such claims are totally unachievable. Chaos theory has shown that even simple non-linear systems are inherently unpredictable." Recently Tomas Kiberger and Bengt Minsson [2] underlined the relevance of physics perspectives for economic processes: "processes in economic systems have important physical aspects that are essential for forming a useful theory. These processes involve conversion of energy and materials and formation as well as breakdown of structure. The conversion processes are of physical necessity dissipative, i.e. they involve production of entropy" and added "physicists have discovered a large number of immutable laws of nature. Some of these are particularly important for the social sciences. Foremost among these are

the first and second laws of thermodynamics. In the context of societal processes, these may be formulated as l. Energy is neither consumed nor produced in economic processes 2.

3 the first and second laws of thermodynamics. In the context of societal processes, these may be formulated as l. Energy is neither consumed nor produced in economic processes 2. Every economic process results in an increase in total entropy." Western science conceives nature in terms of geometric rules and mechanistic laws. Newton's laws, for example, are reversible deterministic laws that imply certainty and assume that time is symmetrical between past and future. To "laws of nature" of this kind, Prigogine adds and counterposes the concept of "events". We know that such laws are not true for living systems, ecosystems, and the events of biology and ecology. In quantum theory and relativity, the two great revolutions in physics this century, the determinism and reversibility of Newton's laws are incorporated unchanged; uncertainty, irreversibility and the role of time are not accorded scientific dignity. This leads to a schizophrenic dualism between being and becoming, between the static description of nature and the irreversible behaviour of living things. It does not seem possible to reconcile classical physics and evolutionary biology. Darwin is left outside on the doorstep as far as certain branches of western science are concerned. On one hand we have the deterministic reversible "laws of nature", and on the other, the laws of thermodynamics and entropy ready to offer us the basis for a new evolutionary physics. The Greek word, entropy, means evolution. Today we know that chemical reactions and biological processes produce entropy or negentropy, distinguish between past and future, and are truly irreversible. We know that in systems far from equilibrium new structures are created, that order arises from disorder and that coherence can emerge. Prigogine underlines the existence of a time paradox: "laws of nature" on one hand that negate irreversibility; on the other, the fundamental time dimension without which it is impossible to conceive our existence. Neither biologically nor cosmologically can nature be described without distinguishing between past and future. We live in an ecosystem kept far from equilibrium by solar radiation. Economic systems and ecosystems are both in a steady state, far from equilibrium, and only dynamic evolutionary models based on irreversible, nonconserved quantities and functions can enable us to understand the complexity of the interactions between natural and man-made capital, between biosphere and system of production, between nature (of which we are part) and economic activity. This is the challenge of physics, economics and ecology for the new millennium. It will be played in the field of thermodynamics and its protagonist will be time. It will be necessary to resist the dual temptations of reductionism: that of separating the parts and eliminating relations, and that of separating a thing from its evolution, seeing it statically in the stationary moment that does not exist in nature. Time irreversibility and time asymmetry are intrinsic properties of nature and govern relations.

4 2 Energy vs. entropy: the scientific foundations of evolutionary thermodynamics An energy flow can lead to destruction (increase in entropy, for example a cannon ball) or organisation (decrease in entropy, for example photosynthesis). The same quantity of energy can destroy a wall or kill a man; obviously the loss of information and negentropy is much greater in the second case. Energy and information are never equivalent. The classical example of the mixing of gases in an isolated system shows us that there can be an increase in entropy without energy input from outside. The point is that E and S are both functions of state, but energy is intrinsically reversible whereas entropy is not. Entropy has the "broken-time" symmetry of which Prigogine speaks. In other words, entropy has an energy term plus a time term that energy does not have. Entropy has an intrinsic temporal parameter. Energy obeys spatial and material constraints; entropy obeys spatial, material and temporal constraints. The time term which is also linked to the quantity of information, does not prevent entropy from being a function of state, Intrinsic time [3], unlike a time interval, is a function of state. Entropy breaks the symmetry of time. If history and the succession of events are of scientific relevance, the concept of function of state should be revised at a higher level of complexity. The singularity of an event also becomes of particular importance: if a certain quantity of energy is spent to kill a caterpillar, we lose the information embodied in the caterpillar. But if this was the last caterpillar, we would lose its unique genetic information forever. The last caterpillar is different from the n-th caterpillar. Stories take place in a setting, the details of which are not irrelevant to the story. What happens in the biosphere, the story of life, depends on the constraints of the biosphere itself. Hence it is important to have global models of the biosphere in terms of space, time, matter, energy, entropy and information, with their respective relations. The 80th anniversary of the first Solvay Conference (radiation theory and the quanta) in 1912 was celebrated at the 20th Solvay Conference (quantum optics) in On this occasion, Prigogine observed that according to Bohr, the measuring apparatus had to be the intermediary between the laws of quantum mechanics, valid on a microscopic scale, and the world of classical physics. Before quantum mechanics, Prigogine continued, this problem did not exist because it was assumed that the dynamics of atoms and large bodies were the same. He went on to say, however, that in quantum theory, the situation was completely different. He asked how Schrodinger's equation could lead to irreversible processes if it was reversible in time. He added that Bohr's intuitions were now confirmed: in order to communicate with nature a common time was needed. It was necessary to read the results of measurements in "our" time, not in the time of Schrodinger's equation. Prigogine treats this problem mathematically in "Dissipative Processes in Quantum Theory" using Poincare's theorem, the model of Friedrichs and an

irreducible representation of the Liouville space. The mathematics is obviously beyond the scope of this work. Prigogine introduces the concept of "quantum chaos".

5 irreducible representation of the Liouville space. The mathematics is obviously beyond the scope of this work. Prigogine introduces the concept of "quantum chaos". In his treatise he defines the limits of orthodox quantum theory, obtains solutions with broken time symmetry, introduces irreversibility at microscopic level and associates life-times with dissipative processes. He inverts the traditional perspective that stable systems are the rule and unstable ones exceptions. He makes dissipation part of the basic microscopic picture. Prigogine concludes that measurement is a way of communicating with nature. Communication requires a common concept of time which emerges from dissipation. Instability, as a consequence of quantum chaos, appears at the basis of our possibility to communicate with the quantum world (the measuring apparatus and the system are described in the same way). He adds that Schrodinger's cat was a living creature and that life cannot be dissociated from irreversible processes. He goes on to say that Bohr was right in the famous debate with Einstein at the 5th Solvay Conference, but that when quantum theory was formulated, dynamic instability and chaos were not elements of normal physics. These concepts now emerged as essential for the selfconsistency of quantum theory. However, he adds, Einstein was right in supposing that the quantum mechanics of his time would not be the final form of quantum theory. In Prigogine's view, the subjective aspects of orthodox quantum mechanics have now been eliminated. The PoincarC divergence is a mathematical fact, independent of the observer. The new formulation of quantum theory forces us to accept a view of the world that incorporates instability and dissipation as basic elements. In this paper Prigogine lays the foundations for evolutionary physics. The scientific schizophrenia that divorced evolutionary biology and mechanics has been superseded: physics and biology are now united. We begin to glimpse the potential of new physico-chemical instruments for tackling the complex study of living systems and evolving ecosystems. The reproducible experiment is exposed for the myth that it was. Ecodynamic models are beginning to appear and give results in complex fields such as sustainable towns, integrated agroenergy systems, biomass and aquatic ecosystems. Physical chemistry comes down from its pedestal of theory and the study of unreal molecular monads and joins the real world, finding applications in nature, society, the hios and the oikos, without loss of rigour or scientific level. Physical chemistry, especially thermodynamics, can play a fundamental role in the description and study of complex ecosystems. This branch of chemistry defines intuitions of evolutionary physics such as entropy, irreversibility and complexity with mathematical rigour. The application of models of physical chemistry to environmental problems requires these intuitions, which are more than a hundred years old, and the scientific experience of all the theoretical and experimental methods gained since then.

6 3 Conclusive remarks As pointed out by Fabiana Malpelli [4] "we are on the threshold of a new age. We feel the weight of history without foundations. Ecological criticism, which is epistemological, ethical and economic together, is both criticism of human arrogance and of reductionism. The first implies an attitude of collaboration and respect (or even reverence). The second implies a search for ways of understanding and representing complexity, and therefore recognition of the complexity of the cognitive process, research into combined use of reason and sense. Among other things, this involves a reappraisal of the antiaesthetic assumption of Newton, according to which all phenomena (including thoughts) can and must be studied and evaluated quantitatively". She adds: " Because classical dynamics is an abstraction in a stable, ordered and deterministic cosmos, divorced from the world of qualities and sensory perception, it could only deny evolution as creator of novelty and complexity. In Newtonian cosmology, the dimension of time is an absolute dimension and motion is reversible or symmetrical with respect to the time coordinate. In the work of Einstein, a denial of irreversibility is dominant and the evolution of the world is relegated to appearance and illusion, counterposed to Plato's world of eternal truths: time is reduced to a spatial dimension and its symmetry and reversibility are ratified." Quantum physics, bifurcations and catastrophe theory introduce discontinuities as basic features of dynamic analysis. Irreversibility is recognised as an inalienable characteristic of natural processes. The thermodynamics of far-from-equilibrium systems developed by Prigogine and the Brussels school brings physical sciences closer to biological sciences and natural sciences closer to humanities. Results of these studies lead to the concepts of irreversibility, fluctuation, threshold, creation of order out of disorder. They have the capacity to bridge matter and life, being and becoming, providing models for understanding phenomena typical of life. Indeed, denial of the time dimension by classical dynamics underlies that disenchantment of modern man that characterises divorce from his environment. Man in his mutability clearly cannot identify with an atemporal deterministic world, perfect in its changelessness. A fusion between human and natural sciences would mean modern man overcoming his alienation; it involves a new look at the concept of time, that will at last lead to a coherent concept of physical reality. The illuminist dream of reason that seeks to dominate nature, rather than living in harmony with its rhythms, is generating monsters of one-way thought which do not observe the timing or modes of nature and know no bounds or limits. Ilya Prigogine 151 is right in claiming that " Science is a dialogue with nature. Over the past this dialogue has taken many forms. We feel that we are at the end of the period which started with Galileo, Copernicus and Newton and culminated with the discovery of quantum mechanics and relativity. This is a glorious period, but it led in spite of all its marvellous achievements to an oversimplified picture

7 of nature, a picture which neglected essential aspects. Classical science emphasised stability, order and equilibrium. Today we discover everywhere instabilities and fluctuations. Our view of nature is changing dramatically. At all levels we observe events associated to the emergence of novelties, we may associate with the creative power of nature. The most common evidence of complexity comes from phenomena at the macroscopic level. Here emphasis is placed on the origin of collective behaviour in multi-unit systems giving rise to new, emergent properties absent at the level of the units when isolated. Bistability, oscillations, chaos, pattern formation and turbulence in hydrodynamics, chemistry and optics provide typical examples. There is increasing awareness that complexity appears also at the microscopic level - for example in the form of complex distribution of molecular and nuclear spectra. The very origin of irreversibility is intimately related to the intrinsic instability generated by the underlying dynamics. Classical dynamics as well as standard quantum mechanics have been built on the paradigm of simple stable systems. As the vast majority of dynamics do not satisfy these conditions, the challenge is to elaborate formulations of dynamics applicable to these more representative systems." We are at the beginning of a "New Physics", incorporating dynamics, instabilities, chaos and irreversibility, an evolutive physics based on Prigogine's assumptions. Our life is not governed by atemporal and deterministic laws, but it is immersed in the flow of time, in constant relation with memory of the past and projection towards the future. References [I] Harding, S., From Earth System Science to Gaian Science, Proc, of the International School Earth and Planetary Sciences, in press, [2] Kiberger, T., Minsson, B., Entropy and economic processes - physics perspectives, Ecological Economics, 36, pp , [3] This parameter is related to the "internal time" and "natural time ordering" of Prigogine and to the concept ofthe arrow of time. [4] Mapelli, F., personal communication. [5] Prigogine, 1. In Tiezzi E., Fermare il tempo. Un'interpretazione esteticoscientifica della natura, Cortina Ed., Milano, 1996.

Dissipative structures in nature and human systems

Design and Nature IV 293 Dissipative structures in nature and human systems E. B. P. Tiezzi 1, R. M. Pulselli 2, N. Marchettini 2 & E. Tiezzi 2 1 Department of Mathematics and Informatics, University of