Charles Darwin's On the Origin of Species, first published in 1859, had two principal goals: to provide evidence that species had not been created separately ("each according to its kind") and to show that natural selection had been the main force behind their proliferation and decent from common ancestors. "If I were to give an award for the single best idea anyone has ever had," the philosopher Daniel Dennett wrote in his 1995 book Darwin's Dangerous Idea, "I'd give it to Darwin, ahead of Newton and Einstein and anyone else." Had Darwin needed a modern bulldog, Dennett would have been a good choice. He calls Darwin's idea that a complex cumulative evolutionary process by means of natural selection is the inevitable result of three simple factors–phenotypic variation, heritability and differential fitness–a "universal acid" that not only explains the biological world but eats its way through just about every part of the natural order. And indeed, Darwinism has successfully conquered scientific disciplines of all sorts, giving rise lately to such fields as evolutionary computer science, evolutionary economics, evolutionary ethics, evolutionary psychology, evolutionary epistemology, and even evolutionary medicine. A bulldog, it seems, was not needed.

Yet, Darwinism always has had and continues to have its critics. On the one hand, religious fundamentalists argue (or rather: declare) that there is no natural process of macro-evolution sufficiently strong to account for the evolution from simpler to more complex organisms through intermediate stages, and some of them even deny that micro-evolution, the cumulative change of a trait within a species, can be explained by means of natural selection. Interestingly, these critics get support from the field of biology itself. Some biologists argue (they really do argue) that natural selection cannot be the main, let alone the only, mechanism behind biological evolution. Stephen Jay Gould and Richard Lewontin famously held that Darwinians tend to assume far too readily that nature is adaptive, i.e. that virtually every organic feature of an organism contributes to its survival and reproduction, thereby ignoring alternative mechanisms of evolutionary change. According to Gould and Lewontin, organisms cannot be understood piecemeal, but must be analyzed as integrated wholes, with so-called 'Baupläne' that are constrained by factors like phyletic heritage, developmental pathways, and general architecture that are often much more important for the evolutionary process than natural selection. They have been joined in recently by researchers from a new field known as 'evolutionary development' ('evo-devo') who argue that latest biological thinking represents a significant contraction of the scope and power of natural selection, since even within a species the occurrence of novel forms apparently fails to correlate with levels of genetic variation sufficient to account for all morphological diversity. Apart from mechanisms such as mutation, translocation and duplication of genes, evo-devo argues, much novelty and biodiversity arises by alterations in gene regulation, and this suggestion has introduced an important new element into evolutionary thinking that goes beyond the Darwinian idea of natural selection.

That there is evolution, the fact of evolution, can nowadays hardly be denied. The How of evolution, however, in particular the idea that natural selection is evolution's main mechanism, is much more controversial. Maybe, then, Darwinism does need a modern bulldog after all. In case Dennett is unavailable, another philosopher is ready to help out: Michael Ruse, in his latest book Darwinism and Its Discontents.

Ruse's book introduces the central arguments, questions, and topics currently discussed in evolutionary theory and related areas such as the philosophy of biology, illustrating nicely how illuminating and powerful evolutionary analyses can be when used properly. Given his lucid and entertaining style and the broad terrain covered by his discussion, Darwinism and Its Discontents may thus be a valuable reading for the interested layman and the average undergraduate student. Nonetheless, Darwinism and Its Discontents also makes a valuable contribution to the debate–usually chiefly restricted to professional academics–about the status of Darwinian analyses and their role in the process of evolution, for Ruse is a uncompromising Darwinist (in the best possible sense of this term) and provides an ardent defense of Darwinian thinking, countering any attacks on it, whether they come from opponents to evolutionary theory in general or from opponents to Darwinian thinking in particular. I will first give a detailed and somewhat longer than usual overview over the terrain covered by Darwinism and Its Discontents to convey to those unfamiliar with the scholarly debates about evolutionary theory a better idea of the kinds of issues discussed, before I turn to some more critical remarks.

Chapter 1 is largely historical, providing an overview over the origins of Darwinism, in particular over the work of Charles Darwin himself. When one is talking about evolutionary theory, one must keep in mind a pivotal distinction: The term 'evolution' denotes a process of development from the simple to the more complex; as such, it is not to be conflated with the term 'natural selection,' which denotes one of several possible mechanisms that drive the process of evolution. While natural selection is a central topic for much of the remainder of the book, chapter 2 is primarily concerned with the process of evolution and its alleged status as scientific fact. Ruse addresses the charge that belief in evolution is not driven by 'hard' scientific evidence but by a chauvinist, intolerant, and doctrinaire philosophical naturalism according to which explanations of natural phenomena may not, by fiat, invoke any non-natural factors. In order to show that evolutionary thinking has a better theoretical foundation than merely an unsubstantiated trust in a philosophical doctrine, Ruse summarizes three scientific arguments for evolution, attributing them to Darwin himself: (1.) the direct evidence we have of cumulative evolutionary change, for instance in animal and plant breeding; (2.) the fact that we have to offer a mechanism, viz., natural selection, which explains the possibility of evolution in a natural world without appealing to any guiding force or 'foresight'; and (3.) the fact that evolution explains a range of diverse and otherwise unexplainable phenomena from fields like paleontology, morphology, embryology, or geographical distribution.

Chapters 3, 4, and 5 tackle three important questions for any Darwinist. (1.) The question about the origin of life: 'How could life have arisen from dead matter by purely natural means?' (2.) The question about the path of evolution: 'How did the development of the biological world proceed since the first appearance of animate life to us modern human creatures?' (3.) The question about the cause of evolution: 'How did the simple manage to evolve into the complex?' When discussing these issues, Ruse responds, among other things, to the charge that the idea of the 'survival of the fittest' often used to explicate the idea of evolution by means of natural selection is a triviality (since those that are 'fit' are just those that survive, so that Darwin's contention boils down to the tautology that those who survive survive), introduces the so-called 'gene's eye view of evolution' introduced by George Williams and Richard Dawkins and explains the virtues and vices of the use of optimality models in evolutionary thinking.

Chapter 6 takes care of a number of scientific objections against natural selection as the main, or even sole, mechanism behind evolutionary change. Ruse responds to Gould and Lewontin's charge that natural selection is not the all-powerful principle Darwinians, blinded by the apparent success of adaptationist thinking, take it to be since there is no reason to think that most living nature is adaptive. He also discusses alternatives to natural selection, like drift, developmental constraints and self-organizing principles, concluding that although they may be important, they do not suffice to diminish the pivotal role of natural selection. Another important issue addressed in chapter 6 is Gould and Eldrige's claim that the history of life does not show the kind of smooth, gradual transitions ('phyletic gradualism') that one would expect if it were indeed the result of unaided natural selection in the way Darwinism envisages it and their alternative account of a 'punctuated equilibrium,' according to which long periods of evolutionary stasis are followed by rapid transitions from one form to another.

Chapter 7 is about humans, their evolutionary past, and the role of Darwinian thinking in the explanation of their evolution. The issues dealt with include the path evolution took since the human lineage separated from the most recent common ancestor we share with other primates, speculations about the causes of human evolution, conjectures about evolutionary explanations of characteristically human traits like thought or language, and the question what evolutionary thinking can contribute to modern discussions about race and other societal matters.

Like chapter 6, chapters 8 and 9 are concerned with rebutting a series of arguments that attempt to show that Darwinism is untenable, but here the focus is on more general objections that are not primarily rooted in recent new findings and developments of modern biology. Ruse points out that the abuse of Darwinian ideas in the thinking of social Darwinists during the late nineteenth and early twentieth century, in the argument for eugenics, and in the various race-theories that eventually culminated in German Nazism was based on a caricature version of Darwinism (deliberately or due to genuine misunderstanding) and not on a sound understanding of Darwinian theory. He also responds to the accusation, substantiated by an appeal to Ernst Haeckl's fraudulent drawings of embryos, Bernard Kettlewell's shoddy research on industrial melanism in the peppered moth, and the so-called 'Piltdown Man' discovered around 1912 in England which turned out to be forged, that the history of Darwinism is in fact a history of dishonesty and fraud, and not one of genuine scientific success as Darwinists contend.

Chapters 10, 11, and 12 are concerned with the role of Darwinian thinking in philosophy, literature, and religion. In the chapter on Darwinism and philosophy, for instance, Ruse attempts to show in what sense evolutionary epistemology and, perhaps more interestingly, evolutionary ethics are possible. Evolutionary ethics usually has a bad reputation because of its association with what is called the 'naturalistic fallacy,' the false idea that from the fact that the world is a certain way we can validly conclude that it ought to be that way. Committing the naturalistic fallacy has led to some very disconcerting views in the past–arguments in favor of eugenics, or in favor of the preservation of race-, class-, and gender-differences, to name only a few–and that continues to shed a bad light on Darwinism. However, as Ruse points out, entirely correctly, the disreputable attempts in the past do not establish that ethics is indeed a stumble block for Darwinists. The fact that we cannot move from an 'is' to an 'ought,' he argues, does not show that there can be no morality, no moral justification or moral responsibility–after all, during the course of evolution we have quite obviously developed an elaborate moral system. What the impossibility of an 'is'/'ought' transition does show, he admits, is that there can be no theoretical justification, based on evolutionary theory, for the particular moral system that in fact evolved. What the Darwinist has, thus, is ethics without (a metaethical) foundation.

I hope this somewhat lengthy summary enables the reader to judge for him- or herself whether or not Darwinism and Its Discontents might make a valuable reading. As far as I am concerned, I am not sure what exactly the intended audience of Ruse's book is supposed to be. The way he presents and arranges the material makes it plain that the book is intended for a broader audience. Given this, however, I am concerned that some parts may seem 'too academic' to most of the audience or simply exceed the capabilities of the intended reader. Ruse's discussion of Kauffman's principle of 'self-organization' as a major factor in evolutionary change, for instance, is way too dense to be useful to the uninitiated, and the same holds for his remarks about the possibility of evolutionary epistemology or evolutionary ethics in chapter 10 or for his brief exposition of the basic principles of population genetics in chapter 5. A further worry is that sometimes Ruse seems to err on the opposite side, simplifying things too much in his struggle to convince the reader of the truth and aptitude of Darwinian thinking, so that sometimes–for instance in the case of Ruse's arguments against Lewontin and Gould's critique of the 'adaptationist program' or alternatives from the field of evolutionary development–Darwinism seems to 'win' only because the arguments of its opponents are not discussed in enough detail. This brings me to a second point of concern. If Darwinism and Its Discontents is written for an audience with more expertise in the field, then Ruse's discussions sometimes seem to be too superficial, ending at exactly the point where things are getting interesting, for instance in his discussion of Kettlewell's flawed study of the peppered moth, where Ruse simply appeals to a more recent study of Michael Majerus without even mentioning the difficulties with Majerus' study that are currently debated in the literature.

Despite these grumpy remarks, I can recommend Ruse's book: it is interesting, engaging and thought-provoking. For the reasons given above, those who are primarily interested in and in need of an introduction to evolutionary theory or the philosophy of biology should be careful when reading it–or, if I may close with that personal remark opt for Griffiths and Sterelny's 1999 Sex and Death: An Introduction to the Philosophy of Biology.

© 2007 Sven Walter

Sven Walter, Ph.D., University of Bielefeld, Germany

Categories: Genetics