The Science and Humanism of Stephen Jay Gould

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Richard York and Brett Clark

Stephen Jay Gould was one of the most important evolutionary theorists since Charles Darwin. His enormous final work, The Structure of Evolutionary Theory, was published shortly before his death in 2002 and will long remain a key text for understanding the natural world and its development. The prominent left wing biologist Steven Rose argues that Gould's book represents "perhaps the most important advance in evolutionary theory since Darwin wrote The Origin of Species".

Gould was also one of the greatest modern popularisers of science. From 1974 to 2001 he wrote a monthly column in the US magazine Natural History. These articles were the basis of a series of books which are among the very best of science writing.

In these essays he covers issues in evolution, natural history and often way beyond. Sometimes he countered opponents, like creationists; sometimes he explained important scientific ideas and debates. The essays were always beautifully written and accessible but never oversimplified.

Gould drew heavily on history, art, architecture and much else including baseball, for which he had a passion, all of which he wove into his arguments to brilliant effect.

Gould was also a politically engaged scientist and made little secret of his leftist views. On occasion he was attacked for being a Marxist - though that was not a label he usually applied to himself. Gould certainly waged war against the right - throughout his working life he battled against the powerful forces in the US who push creationist views.

Another front in Gould's wars was with the IQ industry - the idea that there is a single measurable thing called intelligence, with the usual corollary that this "intelligence" shows genetic differences across races and classes. In 1981 Gould wrote the classic book The Mismeasure of Man which utterly destroyed these arguments.

But Gould was, first and foremost, a working scientist, a palaeontologist studying the fossil record of life on earth. This science was the foundation for all of his contributions to the nature of evolution. At the heart of Gould's arguments - and the core of his final book - is a fight over an understanding of evolutionary theory. In the last decades of the 20th century this battle was often dubbed "The Darwin Wars". These were fought between people like Gould and his allies, such as US Marxist biologist Richard Lewontin, and a group whose best-known figures include British biologist Richard Dawkins, famous for books such as The Selfish Gene, and non-biologists such as US philosopher Daniel Dennett.

Dawkins and others draw on the dominant theme in evolutionary theory since the 1930s known as the modern synthesis. Crudely put, it argues that the only evolutionary mechanism needed to explain the natural world and the whole of evolutionary history is natural selection (differential survival) operating at the level of the gene. All the rich patterns of life's history can be reduced to this single causal level and explanation, or so the argument goes.

Gould powerfully challenges this view, known as reductionism. He argues that while this mechanism is a vital part of evolution, it is only one aspect, a partial picture.

He argues that the natural world has emergent properties at different levels of complexity, and that you cannot reduce causal explanation down to a single level, but instead need to understand each level, and the relations between them. Gould argued that at each level of biological organisation - the gene, the individual organism, the deme (locally breeding population), the species and so on - selection could and did operate, and that understanding evolution meant understanding all these levels and the often complex relations between them.

This approach was grounded in a wider scientific and philosophical challenge to crude and mechanical reductionism. The argument is that you cannot reduce biology to chemistry, or chemistry to physics. Nor can you reduce psychology to biology, or human history to biology. To use a physical picture to illustrate, you cannot explain the behaviour of liquid water in all its features simply at the level of the physics of hydrogen atoms and oxygen atoms. Water has emergent properties which have to be understood at their level: such as liquid flow - with all its complexity.

Gould's view draws on a philosophical and scientific tradition which goes back to Karl Marx' s lifelong collaborator, and important writer on scientific ideas and understanding, Frederick Engels, which argued for this richer historical materialist approach to understanding the natural world, against crude reductionism.

Richard York and Brett Clark have done a great service by writing a concise and readable account of the key aspects of Gould's work - both his scientific ideas and some of his wider philosophical views. I heartily recommend their book to anyone wanting to understand Gould's ideas - and even more strongly recommend reading Gould's own work.

The Science and Humanism of Stephen Jay Gould is published by Monthly Review Press, £14.95