Darwin and Design: Does Evolution Have a Purpose? Michael Ruse. Harvard University Press, Cambridge, MA, 2003. 371 pp. $29.95 (ISBN 067401023X cloth).

For a very long time, I have thought that Michael Ruse's best book was The Darwinian Revolution: Science Red in Tooth and Claw (University of Chicago Press, 2nd ed., 1999). Now I think that Darwin and Design has taken its place. Ruse's unifying themes in this book are design and complexity. He follows these twin notions from the ancient Greeks to Darwin's immediate predecessors and from Darwin himself and beyond to the present. Ruse makes this journey as painless as possible, in large part because of his delightful prose. He also strikes just the right balance between scholarship and comprehension: He knows all the technicalities of the literature that he summarizes, but he does not burden his reader with any of it unless absolutely necessary. I do not know whether Ruse wrote this book with scientists specifically in mind, but it is scientist friendly. Scientists should welcome an opportunity to get a rough idea of what philosophers, theologians, and other scientists and scholars have been trying to get at with respect to design and complexity for the past two thousand years.

Ruse sets out the response of each of his protagonists to three arguments: the argument to complexity, the argument from complexity, and the argument to design. Does the living world exhibit a level of complexity that seems to demand a special kind of explanation? If so, what conclusions can one derive from this complexity? Does it entail a supernatural designer?

Ruse divides his book into three largely chronological sections. First, he presents the various versions of teleology from the ancient Greeks to the Church fathers and such “modern” philosophers as David Hume, Immanuel Kant, and William Paley. Although Paley was nowhere near the philosopher that Hume and Kant were, he was the one who influenced Darwin most directly and extensively. Not infrequently in the history of thought, relatively unsophisticated authors have more impact on subsequent generations than do their more erudite colleagues. Darwin lived while the argument from complexity to design was at its height of popularity, set out time and again in a series of books termed the Bridgewater treatises. Darwin directed his one long argument in the The Origin of Species against Paley and the authors of the Bridgewater treatises. More sophisticated opponents would have to wait their turn. As Ruse puts it,

According to the usual story, after some initial resistance from Darwin's more religiously biased contemporaries, Darwin's theory triumphed. But in fact the amazing thing about Darwin's theory was how unsuccessful it was. Before Darwin, a few natural historians had suggested that species evolve, but the mechanisms that they set out were not very convincing. When Darwin referred to “my theory,” he meant his views about the processes that result in the evolution of species—chance variation and natural selection. After Origin, a fairly high percentage of scientists came to accept the idea that species evolve, but they were not all that enthusiastic about Darwin's mechanism. T. H. Huxley thought that evolution was more saltatory than Darwin supposed and did not think that natural selection was up to the task that Darwin had set it, while Asa Gray wanted to introduce a supernatural element into Darwin's theory.

To make matters worse, very few of the next generation carried on in the spirit of Darwin and Wallace, investigating the processes that lead to the evolution of species. Instead, they turned their attention to reconstructing phylogeny. Not until the end of the 19th century did a reasonably large number of biologists begin to investigate the evolutionary process itself, and they did so almost always as opponents of Darwin's theory. By now the story of the rediscovery of Mendel's laws at the turn of the century is overly familiar. I suspect that most biologists are puzzled when they read about the conflict between the Mendelians and Darwinians. How could the two groups of scientists not see that these two theories are compatible?

In any event, these disputes had one beneficial outcome: They forced biologists to start once again in earnest to work on understanding the evolutionary process itself. Under the leadership of Fisher, Haldane, and Wright, followed by Dobzhansky, Simpson, and Mayr, evolutionary theory was made more quantitative and testable. Ruse gives short but fair discussions of adaptationism, drift, the founder principle, mimicry, punctuated equilibria, levels of selection, game theory, kin selection, the comparative method, optimality models, and so on. He then turns to “formalist” critics. The contrast between form and function was commonplace in Darwin's day. Platonists, primarily Continental Platonists, placed much more emphasis on forms than did their meat-and-potatoes English contemporaries. A role for forms in evolutionary theory has been resurrected in recent years.

All of the preceding discussion prepares the stage for a return to a final treatment of complexity and design. Given all the improvements in contemporary evolutionary theory, how does the argument from design hold up? Ruse begins with nontheistic treatments of design: goal-directed system, functional organization, and human intentions. Then, in the last two chapters, he returns to the idea of God the designer. Here he must distinguish between the United States and the rest of the first-world nations. Only in the United States is the general public so opposed to Darwin's theory. By and large, our schools are not doing a good job of explaining evolutionary theory or the nature of science in general. According to the critics, unless one can see something with one's own eyes, it is “only a theory,” and theories are the sorts of things that one can accept or reject as one pleases.

How do present-day creationists handle present-day evolutionary theory? In large measure, they don't. Instead, they use recent disputes over the evolutionary process to argue that even scientists reject Darwin's theory. In the main, they simply trot out 19th-century objections to parodies of 19th-century evolutionary theory. A case in point is the phrase “chance variation.” When evolutionists say that variations occur by chance, they do not mean that they have no causes at all. The variations that function in the evolutionary process are “chance” only in the sense that they were not introduced for a purpose. They are caused—totally caused—but only by, say, an increase in temperature, not divine fiat. Evolutionary biology is totally naturalistic, as it must be if it is to count as science.