Deep Simplicity: Chaos, Complexity and the Emergence of Life

  • John Gribbin
Allen Lane: 2004. 272 pp. £18.99 0713996102 | ISBN: 0-713-99610-2

The search for simplicity is perhaps the most basic theme of all science. As the late social and political scientist Herbert Simon put it, the purpose of science is “to find meaningful simplicity in the midst of disorderly complexity”. In his new book Deep Simplicity, John Gribbin explores this theme in the context of two great movements of modern science — chaos and complexity — and argues that the discovery of simplicity hiding behind surface complexities will soon explain the origin of life itself.

Gribbin suggests quite plausibly that humans — and, by implication, our societies — are among the most complex things in the Universe. At the atomic level, individual particles follow relatively simple physical laws. It is out of the interactions of many particles, and then of objects made of them, that complexity arises, producing conductors and liquid crystals, biomolecules, living organisms, ecosystems and human culture. On a larger scale, the world again becomes relatively simple, for in the interior of a large planet, or a star, “gravity crushes any structure out of existence”. Complexity occupies a middle world, which is also, probably for good reason, our world.

The aim of the book is to explore how simplicity arises on this level, and how it can be identified. But first Gribbin establishes why complexity, or at least the appearance of complexity, should be expected.

The classical newtonian view of the fully predictable Universe dominated science for two centuries. But as Gribbin points out, this world view actually rested on a vast leap of faith — on the supposition that if scientists were clever enough to solve Newton's equations for any system of interacting particles, their solutions would be just as regular as the periodic motion of two bodies, reflected in the elliptic orbits of the planets about the Sun. In 1890, the French mathematician Henri Poincaré proved otherwise: that the resulting motion can be irregular and unpredictable, even when only three bodies are involved. “It may happen,” Poincaré wrote, “that small differences in the initial conditions produce very great ones in the final phenomena.” This, in modern parlance, is chaos, and it implies — in the more general context of dynamical-systems theory — that scientific prediction over long periods of time is generally impossible.

Gribbin tells the story of the modern rediscovery in the 1960s and 1970s of Poincaré’s insight. This is an exciting tale but has been told before, most notably in James Gleick’s bestseller Chaos (Heinemann, 1988). On the positive side, the discovery of chaos reveals that many highly erratic phenomena, ranging from chemical reactions to fluctuations in biological populations, may actually arise from very simple underlying dynamics. This is one way that simplicity often lies behind complexity.

Gribbin then weaves the story of chaos together with more recent developments, and with a host of topics now gathered together under the term ‘complexity science’. The book moves rapidly from spontaneous pattern formation to the mathematics of fractals and the idea of self-organized criticality, examining its relation to earthquakes, mass extinctions and a vast range of other prominently unpredictable phenomena. The book celebrates the contemporary emphasis, especially in physics, on seeking the explanation of complex phenomena through simple dynamical models of growth and evolution. The lesson is the same everywhere: what appears as surface complexity often has its origins in dynamical simplicity. Importantly, Gribbin points out that modern computers have played a central role in making the complexity sciences possible, altering not only the content of science but the way it is done.

Much of Deep Simplicity will be familiar to anyone who has read about chaos and complexity before, but Gribbin does his usually excellent job of making complicated ideas accessible to a broad readership, and the book would certainly make an excellent non-technical introduction to this way of thinking. One minor shortcoming is that the book could have been written in, say, 1998, and still contained virtually all the same material. This is a little disappointing, as the past five years have witnessed a flowering of the complexity sciences and their successful application to a broad range of scientific topics.

Gribbin is something of a phenomenon of science writing, judging from his prolific output over the past two decades. In Deep Simplicity, perhaps, he doesn’t quite succeed in showing how chaos and complexity will soon “explain the origin of life itself”. But he breathes life into the core ideas of complexity science, and argues convincingly that the basic laws, even in biology, will ultimately turn out to be simple.