Michael Ruse is the Lucyle T. Werkmeister Professor of Philosophy and director of the history and philosophy of science program at Florida State University. He is the founding editor of the journal Biology and Philosophy, and is the author, coauthor, editor, or coeditor of some 38 books, beginning with The Philosophy of Biology, which appeared in 1973. Reading Ruse is always entertaining and frequently enlightening as well. His latest book, Defining Darwin: Essays on the History and Philosophy of Evolutionary Biology, is no exception. Ruse doesn't tell us who his intended audience is, but the book appears to be aimed at the interested nonspecialist who is encountering a semischolarly treatment of Darwinism for perhaps the first time. The essays in the book move along at a brisk clip, seldom tarrying to delve into any specific topic in great detail. The effect is to give the reader a broad overview of Darwinism from its seminal expression in the Origin to the latest debates, thereby whetting an appetite for more.

The book consists of 10 essays on evolution-related topics, 5 of which have been previously published. The essays are grouped (very roughly) in chronological order, with sections of the book dealing with the Origin of Species (one essay), and then three essays each in sections examining “The Early Years” (essays on Kant and evolution, Darwinism and mechanism, and Alfred Russel Wallace), “The Middle Years” (essays on Spencer, Julian Huxley and G. G. Simpson, and evolution and the novel), and “The Later Years” (essays on evo-devo, Darwinian explanations of religion, and evolution as a religion). Each section is preceded by a brief note helpfully describing the essays in that section and pointing out the (sometimes subtle) thematic connections among them. As the subtitle of the book suggests, this is a work on the history and philosophy of evolutionary biology. What becomes clear as one reads the essays is that, for Ruse, the historical and philosophical issues are symbiotically related, with history providing a context for evaluating issues of philosophical significance and philosophical analysis highlighting the historical contexts requiring greater elucidation. Although on a number of occasions (see especially the essay on Huxley and Simpson) Ruse explicitly dons his historian's hat to make a particular point, then explicitly replaces it with his philosopher's cap to make a different point, for the most part the historical and philosophical claims work synergistically and provide mutual illumination.

The underlying theme of the essays and the question that animates them, Ruse tells us in the preface, is the big question of objectivity and subjectivity in science: “Is science about an objective reality and is the aim to describe and understand that reality as best one can, or is science a far more subjective enterprise, influenced by the culture of the day and as much a creation as an invention?” (p. 9). The answer that emerges in the pages of this book is, to a close approximation, “yes.” One way to appreciate this point, Ruse suggests, is to consider the central role of metaphors in science, which provide a “middle way” between the objective and the subjective. As Ruse explains in his essay on “Darwinism and Mechanism”:

The idea that organisms and their subsystems are “machines” is a case in point. According to Ruse, “Seeing nature's parts as machines, as mechanisms, as contrivances, is absolutely crucial for Darwin. Like a vampire before a virgin, the metaphor takes on new life” (p. 63). A key Darwinian research strategy is to think of organisms and their parts as if they were machines, and then to engage in reverse engineering to discover why they are as they are. One of Darwin's books, On the Various Contrivances by which British and Foreign Orchids Are Fertilised by Insects (1862), is a classic of this type of reasoning. The idea of organisms and their parts as machines was common in the intellectual milieu in which Darwin wrote, starting perhaps with the work of René Descartes in the 17th century, and finding its apogee in the natural theology of Archdeacon William Paley. Yet insofar as this metaphor leads the scientist to discover the true causes of natural phenomena, it produces objective knowledge. Scientific knowledge is thus both deeply influenced by the culture in which it is produced (the “subjective” element), and also objective in the sense of providing genuine insights into nature. The big question of objectivity and subjectivity in science is thereby neatly resolved—so long as one doesn't press it further.

As always, Ruse's prose is eminently readable. (The irreverent essay on the hapless and unfortunate Alfred Russel Wallace borders on the hilarious.) Many of the essays read as if they are informal lectures, and indeed Ruse tells us that all of the essays in the book were tried out in lecture halls. He writes as someone with a deep and intimate familiarity with all things Darwinian, permitting the narrative to carry the reader along with a sense of seeming effortlessness. Ruse's comments about Darwin's Origin of Species apply equally to the present work: “His warm and easy style makes it exceptionally easy to follow his thinking. Few will come away confused as to the points he is making” (p. 18). Ruse achieves this mellifluous effect by using broad brushstrokes to make his points rather than by delving deeply into his topics or by seriously wrangling with objections or counterarguments. One gets the sense that Ruse wants to keep the discussion moving. The result is jaunty readability at the cost of some precision, although given the presumed target audience for this book, this seems like a fair trade.

Whether readers will agree with all the points Ruse makes is another matter. Occasionally he makes claims plausible enough for readers who simply want to enjoy a good read, but that might raise eyebrows among those who have devoted their professional careers to understanding evolution and evolutionary biology. For example, he writes, “the chief feature of the organic world is its adaptive or organized complexity” (p. 21). To be sure, adaptation is certainly one of the chief features of the organic world that deserves our attention, but there are others as well—biological diversity, for example. What aspect of nature one chooses to privilege for explanatory purposes may seem insignificant, but it can have consequences for how one comes to understand the evolutionary process and for which problems one deems worthy of serious attention.

Likewise, many problems over which much ink has been spilt (e.g., whether evo-devo is in tension with an adaptationist view of evolution, how Darwinian and Christian worldviews can be reconciled, etc.) are dealt with in a fairly breezy manner; Ruse implies that he doesn't see what all the fuss is about (e.g., p. 216). Early in the book he writes: “Evolution is true and natural selection is its mechanism. No more, but certainly no less” (p. 26). This is shockingly simplistic (presumably deliberately so, since Ruse assuredly understands better than most how dauntingly complicated the issues really are). Ruse's energetic writing style and unbounded enthusiasm for an adaptationist interpretation of Darwin's theory can as easily convey to someone coming to these issues for the first time, or without much training in the history and philosophy of science, that most of the interesting problems arising in connection with Darwin's theory are pretty easy to solve with just a bit of historical investigation and philosophical analysis (hence the tongue-in-cheek title of this review). To achieve the breadth of historical sweep and concise take-home message he is seeking, Ruse has to skim the surface of many topics that could easily be subjects for sustained discussion. This is, however, a minor shortcoming that hardly begins to detract from the great value of this book. Its intended audience is likely to come away with a fresh understanding of Darwin's great theory, and with gratitude to Ruse for being such an engaging and convivial tour guide. Defining Darwin is a valuable contribution to the literature emerging from the bicentennial celebration of Darwin's birth. It deserves a wide readership.