Values in scientific ventures

"The presence of a body of well- instructed men, who have not to labour for their daily bread, is important to a degree which cannot be over-estimated; as all high intellectual work is carried on by them, and on such work material progress of all kinds depends, not to mention other and higher advantages." Thus Charles Darwin, who when he was not making intellectual revolution could be as smugly self-serving as any eminent Victorian.

And what about when he was making intellectual revolution? Do assumptions such as these lie at the heart of his formulation of evolution by natural selection? The suspicion has lingered ever since On the Origin of Species and is still heard today as a more sophisticated descendant of Darwin's theory begins to make inroads into other disciplines. So the development of that theory makes an intriguing case study to help Michael Ruse deal with a wider contemporary preoccupation. Does science approach knowledge of reality, or is it simply the result of social and cultural values operating on the observations at hand?

Ruse, fresh from his monumental review of progressivism in evolutionary theorising in Monad to Man, is trying to do several hard things in this smaller book. He wants to cool the sectarian heat of the science wars enough to tackle what he regards as philosophically serious issues underlying the debate. And he aims to do so in a way accessible to the general reader. He succeeds pretty well on both counts, though that success takes a while to build.

The book starts with a nod to the Alan Sokal hoax, a physicist's celebrated lampooning of slipshod relativism. But Ruse is quick to aver that, despite some authors' excesses, the sociological turn in history and philosophy of science has produced material that is "simply stunning". Where does it leave the conventional picture of scientific knowledge? He dramatises the issues by drawing thumbnail sketches of Karl Popper and Thomas Kuhn, as representatives of objectivism and relativism, respectively. The way to resolve the issue between them - or their disciples - he suggests, is empirical.

There follows a treatment of ten evolutionary theorists, whose careers span more than 200 years. Ruse looks at the works and words of Erasmus Darwin and at his grandson Charles. The rest are 20th-century writers, starting with Julian Huxley and Theodosius Dobzhansky, moving on to the popular evolutionists whose disputes have fascinated so many readers in the past 25 years - Richard Dawkins, Stephen Jay Gould, Richard Lewontin and Edward O. Wilson. Ruse finishes with two important contemporary figures less well known to the public, Geoffrey Parker and Jack Sepkoski, one renowned for adaptationist studies of behaviour, the other for analysing the dynamics of change in the palaeontological record.

Much, of course, has changed. We begin with the energetic versifying of a country doctor who strung together anecdotes in the service of his progressivist philosophy, and end with brilliant technicians who test the predictions of computer models against mountains of painstakingly accumulated data. Along the way, Ruse suggests, we also see a shift from the dominance of cultural values towards epistemic ones. What matters in evaluation of theories are values, culturally supported to be sure, such as predictive accuracy, coherence, consistency, unifying power and fertility - values considered to help diagnose truthfulness. Those values have not changed much, but the determination to stick to them has.

There are obvious problems with Ruse's progressivist narrative, as he acknowledges. One is that many of the writers he examines have devoted enormous energy to promoting cultural values that they believe are underwritten by their science. He deals with this by trying to draw a clear distinction between "professional" and "popular" writing and by suggesting that the worthy scientists have expelled the cultural from their professional works.

This is unconvincing. Consider Wilson's 1970s trilogy, in which the final chapter of each book prefigures the next. Does the popular writing start somewhere in The Insect Societies, in Sociobiology , or not until we reach On Human Nature ? There may be a continuum here, but there are no clear demarcations. Even if we look at Wilson's more technical output in the journals, it is surely more satisfying for any proper biographical or historical treatment to see the work as all of a piece.

The second difficulty Ruse faces more directly. Even if the evaluation of theories is based on epistemic criteria, their formulation may still bear the impress of cultural values. The dependence of theorising on metaphor is as heavy as ever - whether we are dealing with the struggle for existence and natural selection or using the more recent language of adaptive landscapes, dynamic equilibria or arms races. Even in work of the highest professional standards, Ruse says, "through the language, the ideas, the pictures, the models and above all the metaphors that evolutionary biology uses, culture comes rushing right back in".

So is there a final answer to Ruse's overarching question? In theory, he suggests, it might be possible to dispense with metaphors. In practice, no scientist ever does, or even should. But this does not mean that subjectivism rules. In fact, he argues, this kind of history cannot speak to realism versus non-realism, only to whether science is somehow special. Even here, though, the answer is ambiguous. Science is special because of its standards, but also not special, because of its culture. Both objectivists and subjectivists are right, in other words.

This is a more satisfying conclusion than it sounds in summary because of the care with which Ruse works up to it. There is still much more to discuss, notably the role of communities of researchers, not just individuals, in building epistemic standards into scientific practice. But Ruse's consistently good-humoured book is a fine example for anyone who wants to approach the science wars constructively. And it gets pretty close to persuading the sceptical reader that popular epistemology might be a viable enterprise.

Jon Turney is senior lecturer in science and technology studies, University College London.