The Extended Phenotype

by Richard Dawkins

  Dawkins, like a philosopher, is primarily concerned with the logic of the explanations we devise to account for these processes and predict their outcomes. But these explanations are scientific explanations, and Dawkins (along with many others) wants to claim that their implications are scientific results, not just the tenets of an interesting and defensible philosophy. Since so much is at stake, we need to see if this is good science, and for that, we need to check out the logic down in the trenches, where the data are gathered, where the details matter, where relatively small-scale hypotheses about manageable phenomena can be actually tested. The Selfish Gene was written for educated lay readers, and glided over many of the intricacies and technicalities that a proper scientific assessment needs to consider at length. The Extended Phenotype was written for the professional biologist, but so graceful and lucid is Dawkins’s writing that even outsiders who are prepared to exercise their brains vigorously can follow the arguments, and appreciate the subtlety of the issues.

  For the professional philosopher, I cannot resist adding, there is a feast: some of the most masterful, sustained chains of rigorous argument I have ever encountered (check out Chapter 5, and the last four chapters), and a host of ingenious and vivid thought experiments (check out p. 143, and p. 241, among many others). There are even some sidelong but substantial contributions to philosophical controversies undreamt of by Dawkins. For instance, I take the thought experiment about the genetic control of mud-gathering by termites on pp. 202–3 to provide useful insight on theories of intentionality—especially on the debate I have had with Fodor, Dretske, and others about the conditions under which content can be ascribed to mechanisms. In philosophical jargon, pure extensionality reigns in genetics, and this makes any labelling of phenotypic traits ‘a matter of arbitrary convenience’ but not, for that reason, unmotivated by our interest in drawing attention to the most telling facts about the situation.

  For the scientist, there are testable predictions aplenty—about such varied topics as, for instance, wasp copulation strategies (pp. 78–9), sperm size evolution (p. 143), the anti-predator behaviour of moths (p. 147), and the effects of parasites on beetles and freshwater shrimps (p. 216). There are also crisp, clear analyses of problems—about the evolution of sex, conditions of intra-genomic conflict (or genomic parasites), and many other initially counter-intuitive topics. His cautionary review of the pitfalls to be avoided in thinking about the green beard effect and its neighbours is an indispensable vademecum for anybody who ventures into that confusing territory.

  This book has been required reading for any serious student of neo-Darwinian evolutionary theory since it first appeared in 1982, and one of the striking effects of re-reading it today is that it provides a time-lapse snapshot of the glacial pace of criticism. Stephen Jay Gould and Richard Lewontin in the United States, and Steven Rose in the United Kingdom, have long warned the world about the ‘genetic determinism’ that supposedly rises menacingly out of Dawkins’s gene’s-eye view of biology, and here in Chapter 2 we find all their most recent criticisms already handily rebutted. You would think that in almost twenty years his opponents would have come up with some new angle, some new crack into which they could drive a subversive wedge or two, but, as Dawkins remarks in another context in which there has been no evolution, ‘there is apparently no available variation for further enhancement’ in their thinking. How much more satisfying, when faced with the task of replying to your most vehement critics, to be able simply to republish what you said on the topic many years ago!

  What is this dread ‘genetic determinism’? Dawkins (p. 10) cites a 1978 definition by Gould: ‘If we are programmed to be what we are, then these traits are ineluctable. We may, at best, channel them, but we cannot change them either by will, education, or culture.’ But if this is genetic determinism—and I have seen no seriously revised definition from the critics—then Dawkins is no genetic determinist (and neither is E. O. Wilson, or, so far as I know, any well known sociobiologist or evolutionary psychologist). As Dawkins shows, in an impeccable philosophical analysis, the whole idea of the ‘threat’ of ‘genetic’ (or any other kind of) determinism is so ill-thought-out by those who brandish the term that it would be a bad joke if it weren’t a scandal. Dawkins doesn’t just rebut the charges in Chapter 2; he diagnoses the likely sources of the confusions that make this such a tempting charge, and as he notes, ‘There is a wanton eagerness to misunderstand.’ Sad to say, he is right.

  Not all criticisms of neo-Darwinian thinking are so misbegotten. Adaptationist thinking, the critics say, is seductive; it is all too easy to mistake an unsupported just-so story for a serious evolutionary argument. This is true, and time and again in this book Dawkins deftly exposes tempting lines of argument that run foul of reality in one way or another. (For a few striking examples, see pp. 72, 76, 155, 263.) On p. 38, Dawkins makes the very important point that a change in the environment may not just change the success rate of a phenotypic effect; it may change the phenotypic effect altogether! So much for the standard, and boringly false, charge that the gene’s-eye point of view must ignore or underestimate the contribution of changes (including ‘massively contingent’ changes) in the selectional environment, but the fact remains that adaptationists often do ignore these (and other) complications, which is why the book fairly bristles with warnings against facile adaptationist reasoning.

  The charge of ‘reductionism’, another standard epithet applied to the gene’s-eye perspective, is perversely inappropriate when levelled at Dawkins. Far from blinding us to the marvels of higher levels of explanation, the idea of the extended phenotype expands their powers by removing crippling misconceptions. As Dawkins says, it permits us to rediscover the organism. Why, if phenotypic effects do not have to honour the boundary between organism and ‘outside’ world, are there (multicellular) organisms at all? A very good question, and one that one probably wouldn’t ask—or ask well—if it weren’t for the perspective that Dawkins offers. Each of us walks around each day carrying the DNA of several thousand lineages (our parasites, our intestinal flora) in addition to our nuclear (and mitochondrial) DNA, and all these genomes get along pretty well under most circumstances. They are all in the same boat, after all. A herd of antelope, a termite colony, a mating pair of birds and their clutch of eggs, a human society—these groupish entities are no more groupish, in the end, than an individual human being, with its trillion-plus cells, each a descendant of the ma-cell and pa-cell union that started the group’s voyage. ‘At any level, if a vehicle is destroyed, all the replicators inside it will be destroyed. Natural selection will therefore, at least to some extent, favour replicators that cause their vehicles to resist being destroyed. In principle this could apply to groups of organisms as well as to single organisms, for if a group is destroyed all the genes inside it are destroyed too’ (p. 114). So are genes all that matter? Not at all. ‘There is nothing magic about Darwinian fitness in the genetic sense. There is no law giving it priority as the fundamental quantity that is maximized… . A meme has its own opportunities for replication, and its own phenotypic effects, and there is no reason why success in a meme should have any connection whatever with genetic success’ (p. 110).

  The logic of Darwinian thinking is not just about genes. More and more thinkers are coming to appreciate this: evolutionary economists, evolutionary ethicists, and others in the social sciences and even in the physical sciences and the arts. I take this to be a philosophical discovery, and it is undeniably mind-boggling. The book you hold in your hands is one of the best guide-books to this new world of understanding.

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