The purpose of Michael Ruse's newest book is to "defend Darwinism from false (or misguided) friends as well as from real enemies" (p 237). To this end he revisits themes he has addressed at book length in the past, including: (1) providing a historical context for Darwin's theory (1979, 2003); (2) demarcating the appropriate relations between science and religion (2001); and (3) evaluating debates among those who consider themselves to be Darwinians (1979, 2000). There is thus a considerable range of topics in this book, with chapters devoted to whether Darwinian evolution can be considered a "fact", whether there are constraints on the power of natural selection, and whether evolution needs to tread within religious waters, among other topics. Because of this breadth, Darwinism and its Discontents should prove useful to those familiar with any of these controversial topics, whatever their level or area of expertise. It may not be an easy read for novices, however, as Ruse moves too quickly for someone without at least some background in these debates. Still, he provides many references for each of the topics covered, and a substantial bibliography. So readers are guided to whatever background material they may need.
Can we meaningfully speak of the "fact" of evolution? Chapter two addresses this issue by distinguishing different senses of both "fact" and "theory" (for "fact", consider the differences between "My car is green" and "The earth is in orbit around the sun"). Once simple observational descriptions are distinguished from inferences based on reliable evidence, there is no oddity or impropriety in labeling the evolution of organisms and their constituent parts a "fact". "Judged against the kinds of criteria and practices that we normally apply and use when making inferences, the evidence for the fact of evolution is very, very solid" (p 45). Indeed it is.
Ruse reviews a representative sample of direct evidence for both human-directed organic change and examples from nature (dogs and hybrid corn/industrial melanism and resistance to insecticides), to show that there is good support for the fact of substantial organic change, as well as for "selection" (artificial or natural) being causally efficacious in the process. Then he (correctly) argues that the bulk of the evidence for Darwinian evolution is indirect, and based on consilience (explanatory power, especially involving data from a variety of areas or by continuing to seamlessly cover new data). This is a good chapter for use as an antidote against creationist and "intelligent design" advocates who use non-scientific senses of "fact" and "theory" to try to tag Darwinian evolution as "philosophy" or even "religion" (thus on a par with supernaturalism).
Two chapters (five and six) consider one of the hottest areas of controversy within evolutionary biology, namely, is natural selection the only (or at least by far the predominant) cause of evolutionary change? Even non-specialists familiar only with the popular science literature will recognize echoes of this controversy associated with Stephen Jay Gould and Richard Dawkins (and their various supporters). To what extent can we assume adaptationism and/or optimality in our construction of evolutionary models? Do self-organizational, developmental, or structural constraints on functional characteristics of organisms shaped by natural selection limit its efficacy, or require additional explanatory models? Embedded within these general questions are issues such as (1) whether human-like intelligence was to be expected from the Darwinian process (or generally, whether "progress" is necessary or ubiquitous in evolutionary history); and (2) whether history and contingency or reverse-engineering and optimality provide better guides for understanding evolutionary processes.
To some extent intuitions here depend on what sort of data are taken as paradigmatic. If one stresses examples of arms races and cases that look very much like products of direct design, adaptationism and the ubiquity of selection may seem paramount. If instead one stresses "panda's thumb" sorts of cases that are relatively clumsy (or due to contingent historical pathways instead of near-optimal solutions to design problems), internal and external constraints may seem to exercise more of a role. Ruse, I think, does a good job of steering between Charybdis and Scylla here, while favoring adaptationism and the use of optimality models, at least methodologically. He explains his preferences while backing away from more extreme claims that seem to deny legitimate evidence for historical and other constraints (which only fuel popular debates that have generated more heat than light).
Many will disagree with the details of his assessment, but, given the present state of controversy, that is to be expected. Ruse certainly doesn't settle these issues here, but he does provide what I think is a reasonable and fair summary. Those not familiar with these issues could do much worse than beginning with these chapters. Those who are more knowledgeable (and/or partisan), will find a well-mannered and thoughtful treatment.
What about creationism and/or "intelligent design"? Here some readers might be a bit disappointed. While Ruse has weighed in on such issues through most of his professional career (see Ruse 1982, 2003, 2005), and has also participated in public debates and testified at trials, he says very little about "the enemy" in this book. To be sure, he shows clearly in chapter three that anyone opposing a basic evolutionary pattern in the fossil record or comparative anatomy or comparative molecular biology is not supported by the evidence from these areas. And in chapter twelve he makes it clear that no version of direct design can now hope to provide or supplement biological explanations (that is, natural theology has no scientific role to play), and takes a brief swipe at the bacterial flagellum totem that has become the icon of the intelligent design movement. On the other hand, this battle is not his major concern.
What he does say about evolution and religion in chapter twelve, however, is important. Characteristically, he distinguishes Darwinian evolution as science from any metaphysical position. Its authority extends to biological processes and structures, and no further. It simply cannot adjudicate issues concerning spirituality and the supernatural (though it can certainly exert its legitimate — and hard-earned — authority anywhere religiosity is extended to biological claims). This, too, is controversial, as anyone who has read Richard Dawkins's The God Delusion (2006; the title says it all) can testify. Still, I find Ruse's position both plausible and important, and well worth considering before weighing in on this issue (see also Ruse 2001, 2003).