Rottenness is all

John Maynard Smith

  • Order out of Chaos: The Evolutionary Paradigm and the Physical Sciences by Ilya Prigogine and Isabelle Stengers
    Bantam, 290 pp, $8.95, April 1984, ISBN 0 553 34082 4

This is an ambitious book which suggests that a new picture of the nature of the universe is emerging from the study of thermodynamics, and that this picture will heal the breach between the scientific and the poetic view of man. Prigogine’s distinction as a scientist – the Nobel Prize for Chemistry in 1977 – requires that we take his views seriously, at least on the first of these claims. The major part of the book is devoted to explaining, in non-mathematical language, the new science that the authors see emerging, and to which Prigogine helped to give birth. The ideas are hard, but I think they succeed. There are places, particularly in their treatment of quantum theory, where readers without some previous knowledge may lose the thread; certainly I did. But anyone prepared to make a serious effort will get some insight into what is happening.

In this review, I aim to do three things. First, I will explain the new thermodynamics; here I will try to follow the authors’ account, not criticise it. Second, I will say something about the relevance of their ideas to biology. Finally, I will comment briefly on their significance for man’s view of himself.

The authors see the history of the physical sciences as dominated by two apparently incompatible approaches, dynamics and thermodynamics. Dynamics, stemming from Galileo and Newton, sees the world as deterministic and reversible. As Laplace argued, it follows from the dynamical world picture that, given the positions and velocities of all the particles in the universe at any instant, an all-powerful intelligence could calculate the future. It also follows that if, at some instant, the direction of motion of every particle was exactly reversed, then the universe would return to the states it had occupied at earlier times. To put the same point in another way, if a film of some sequence of events was run forwards and backwards, it would be impossible for a viewer to tell which direction was correct.

This deterministic and reversible picture is as true of Einstein’s dynamics as of Newton’s. It has no place for our subjective view of time. It is as if the whole past and future were eternally present, although we are forced to experience events in a particular sequence, just as, in the cinema, the whole reel of film is present all the time, but we are forced to view the frames in sequence. This dynamic picture seems to be contradicted by everyday experience, not only of subjective time, but also of the irreversible nature of most events. Shown a film, we have no difficulty in deciding whether it is being run in the correct order. Smoke does not flow towards a cigarette end as the cigarette lengthens.

Since the beginning of the 19th century, scientists have been increasingly interested in processes that do not run backwards. This interest originated from an effort to understand heat engines. A steam engine converts the chemical energy in coal into mechanical work: you cannot run it backwards, to turn mechanical work into coal. It will help to consider a simpler example of an irreversible process. A drop of water falling on the surface of a lake causes waves, which spread out as concentric rings, diminishing in amplitude as they go, until finally they disappear, leaving the lake smooth once more. One never sees a series of concentric rings converging on a point, and propelling a drop of water into the sky. If we ask what has happened to the energy of the water drop when the lake finally becomes smooth, the answer is that the velocity of the water molecules has increased infinitesimally: in other words, the lake has got a little hotter.

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