The philosophy of social constructionism claims that the "nature" that scientists pretend to study is a fiction cooked up by the scientists themselves — that, as Bruno Latour puts it, natural objects are "the consequence of scientific work rather than its cause". In this view, the ultimate purpose of scientists' theories and experiments is not to understand or control an imagined "nature", but to provide objective-sounding justifications for exerting power over other people. As social constructionists see it, science is an imposing but hollow Trojan horse that conceals some rather nasty storm troopers in its belly.
Over the past decade, this hostile picture of science has become the conventional wisdom in many academic circles. In this book, the Canadian philosopher and historian Michael Ruse offers an empirical test of these doctrines. If social constructionism is true, he argues, then the political and moral content of a science should remain more or less constant throughout its history. If social constructionism is false, then these "cultural values" should be increasingly shouldered aside in favor of what he calls the "epistemic values" of science itself — predictive accuracy, internal coherence, consistency with other scientific theories, fertility, simplicity, and unifying power.
The example that Ruse chooses for his test is evolutionary theory, which is his special province as a historian. After surveying the works of 10 successive writers on evolution, Ruse concludes that epistemic values have advanced markedly at the expense of the cultural values. Back in the 1790s, the evolutionism of Erasmus Darwin (Charles's grandfather) was mainly a rhetorical prop for his Whig politics and Deism. Two centuries later, Ruse has to strain hard to squeeze a few drops of ideological content out of such recent work as Geoffrey Parker's studies of sexual selection in dung flies and Jack Sepkoski's analyses of the statistics of extinction rates.
Does this prove that the social constructionists are mistaken? Well, yes and no. "Science is special," Ruse concludes, "and this is because of its standards; the critics [of science] were wrong in arguing otherwise. But it is also true that science is not special, and this is because of its culture; the defenders were wrong in arguing otherwise." Even though explicit moral and political values gradually get pushed out of a maturing science, Ruse thinks that science remains saturated with other elements drawn from the surrounding culture. Scientific language, he argues, has to make use of metaphors, which drag in cultural themes and assumptions having nothing to do with science as such. For instance, scientists diagram evolutionary relationships as trees; "trees in our culture are associated with upward striving"; our culture associates the direction "up" with improvement — and therefore we tend to think of evolutionary change as progressive, tending always to make living things higher, better, or more advanced than their ancestors (p 239). And so on.
We can all agree that cultural themes commonly influence scientific thought. But I wasn't persuaded that they always do so, or that metaphors are as pervasive and important in science as Ruse thinks they are. In the particular case mentioned above, I doubt that the tree metaphor prompts us to think of evolution as progressive. After all, we also say that organisms are "descended" from their ancestors; but that metaphor doesn't tempt us to think of evolution as a downhill slide. It seems to me that the historical progressivism of evolutionary thought is just one aspect of a general post-Enlightenment optimism about the future. This optimism has more to do with erosion of belief in the Apocalypse than with the fact that trees grow upward.
Despite the book's subtitle, Ruse doesn't come to grips with the central question here: did evolution really occur? If it did, then there must be something profoundly wrong with social constructionism. I don't see how one can seriously contend that the world is a human construct if we concede that people evolved from nonhuman animals. Unlike the theories of non-historical, experiment-centered sciences like physics and chemistry, evolutionary theory seems fundamentally at odds with social constructionism. This might be why some prominent social-constructionist academics favor bringing creation science into the public schools.
Although Ruse is disappointingly inconclusive about his main topic, anyone who is interested in the "science wars" controversy or in the history of evolutionary thought will find this book fascinating and rewarding. The prose is masterful — relaxed, colloquial, rich in information, and suffused with flashes of malicious wit and delicious historical tidbits. (I will never again think of Erasmus Darwin without recalling Ruse's observation that he had a semicircular notch cut into his dining table, so that he could belly up to his food.) Ruse displays a marvelous gift for capturing the gist and importance of complicated scientific and philosophical arguments in a few words. His first chapter, an even-handed summary and critique of Popper's and Kuhn's conflicting views of science, is surely the best thing ever written on this subject in 24 pages. Taken together, Ruse's sketches of the ideas and careers of his 10 exemplars — the 2 Darwins, Julian Huxley, Dobzhansky, Dawkins, Gould, Lewontin, EO Wilson, Parker and Sepkoski — provide an entertaining outline of evolutionary thought, which touches on the works of a lot of other leading evolutionists and fits them into their historical and cultural context.
One caveat: Ruse is surprisingly harsh towards authors who wrote books for popular audiences, which he treats as a defect in their work. I can see his point where Julian Huxley is concerned, but I think he is unfair to Stephen Gould. Ruse's disdain for popularizers seems odd in a book that is itself so deft and ingratiating in making all these complicated issues accessible to the general reader.