Richard Dawkins did not invent naïve gene selectionism (see T&R X) but he spread it far and wide with the publication of The Selfish Gene. Let's follow his logic, beginning on page 6 of the 1989 paperback edition:
This book will show how both individual selfishness and individual altruism are explained by the fundamental law that I am calling gene selfishness. But first I must deal with a particular erroneous explanation for altruism, because it is widely known, and even widely taught in schools. This explanation is based on the misconception that I have already mentioned, that living creatures evolve to do things 'for the good of the species' or 'for the good of the group'.
There's the caution against naïve group selectionism. Good for you, Richard! Now for the explanation of why it is naïve:
[A] group, such as a species or a population within a species, whose individual members are prepared to sacrifice themselves for the welfare of the group, may be less likely to go extinct than a rival group whose individual members place their own selfish interests first. Therefore the world becomes populated mainly by groups consisting of self-sacrificing individuals. This is the theory of 'group selection', long assumed to be true by biologists.
Right! This explains how "for the good of the group" traits might evolve. Now for the explanation of why they might not evolve.
The quick answer of the 'individual selectionist' to the argument just put might go something like this. Even in the group of altruists, there will almost certainly be a dissenting minority who refuse to make any sacrifice. If there is just one selfish rebel, prepared to exploit the altruism of the rest, then he, by definition, is more likely than they are to survive and have children. Each of these children will tend to inherit his selfish traits. After several generations of this natural selection, the 'altruistic group' will be over-run by selfish individuals, and will be indistinguishable from the selfish group. Even if we grant the improbable chance existence initially of pure altruistic groups without any rebels, it is very difficult to see what is to stop selfish individuals migrating in from neighboring selfish groups, and, by inter-marriage, contaminating the purity of the altruistic groups.
Done. Allow me to make three observations about these passages.
1) Dawkins' portrayal of within- and between-group selection is utterly standard, and that's a good thing. Throughout the T&R series, I have stressed the simplicity of the group selection controversy. From Darwin to Dawkins, it's all about what I have called the original problem (see T&R II).
2) Dawkins implies that between-group selection (described in the second passage) is no match for within-group selection (described in the third passage), but he provides no proof. Models (such as the modified haystack model), experiments, and field studies are required to make this determination, not rhetorical flourishes.
3) The status of genes as replicators -- what Dawkins calls the fundamental law of gene selfishness -- is utterly beside the point. Genes are the replicators regardless of whether altruism wins or loses in Dawkins' own scenario (also see T&R X). Using the replicator concept to argue against group selection is arguably the greatest case of comparing apples with oranges in the annals of evolutionary thought!
I do not believe the cynical adage "science progresses -- funeral by funeral" but I worry that it might be the case for Richard Dawkins on the subject of group selection. In my dreams, I imagine him reading my modified haystack model and saying "Well done, David! I have been wrong all these years. It turns out that a gene coding for altruism can evolve on the strength of between-group selection, even when it is selectively disadvantageous within groups. I do think it is important to keep in mind, however, that when altruism evolves by group selection, it is still an example of gene selfishness because the gene for altruism is more fit than the gene for selfishness, all things considered."
Scientists would clap their hands red at such an act of nobility, but it hasn't happened yet. Instead, Dawkins has behaved like a cowboy fighting off the Indians in an old western movie. When one gun runs out of ammo, he grabs another and another. Here are three guns that have run out of ammo.
The selfish gene gun. As we have seen, this gun didn't have any bullets to begin with.
The vehicle gun. Recall that if individual organisms don't qualify as replicators, they must quality as something else to be so manifestly well adapted. That "something" is variously called "interactors", "targets", or "vehicles" (Dawkins' term) of selection. In one of Dawkins' famous metaphors, genes in individuals are like rowers in a rowing crew. Since they are literally "all in the same boat", they must "pull together" to win the race. As soon as Dawkins threw away the selfish gene gun, he started to claim that groups fail as vehicles because individuals in groups are not completely bound together in a common fate in the same way as genes in individuals. But this was never a requirement for group selection to occur! The groups in the haystack model and in Dawkins' own portrayal of group selection quoted above aren't like individuals in this respect, but they suffice for altruism to evolve despite its selective disadvantage within groups.
The extended phenotype gun. When the vehicle gun didn't work, Dawkins decided to bury the vehicle concept altogether by describing genes as having extended phenotypes. Two examples of extended phenotypes are a bird's nest and a beaver's dam. The first is an individual-level adaptation in conventional terms; birds that build better nests raise more offspring than birds in the same group that build worse nests. The second is a group-level adaptation in conventional terms; beavers that build better dams are providing a public good for all of the beavers in the pond at their own expense. The fact that the genes result in alterations of the physical environment in both cases is irrelevant. In short, the concept of extended phenotypes doesn't address the original problem and certainly doesn't provide a novel solution.
With the Indians closing in, Dawkins has now started to throw chairs, bite, and kick. Consider his response to my recent article with Edward O. Wilson in American Scientist magazine titled "Evolution 'For the Good of the Group'"
Genes Still Central: David Sloan Wilson's lifelong quest to redefine "group selection" in such a way as to sow maximum confusion--and even to confuse the normally wise and sensible Edward O. Wilson into joining him--is of no more scientific interest than semantic double talk ever is. What goes beyond semantics, however, is his statement (it is safe to assume that E.O. Wilson is blameless) that "Both Williams and Dawkins eventually acknowledged their error [that the replicator concept provides an argument against group selection]...I cannot speak for George Williams but, as far as I am concerned, the statement is false: not a semantic confusion; not an exaggeration of a half-truth; not a distortion of a quarter truth; but a total, unmitigated, barefaced lie. Like many scientists, I am delighted to acknowledge occasions when I have changed my mind, but this is not one of them. D.S. Wilson should apologize. E.O. Wilson, being the gentleman that he is, probably will.
Gracious! What a hierarchical guy! Dawkins acts as if he is the No. 2 monkey, kowtowing to the No. 1 monkey (Ed) while dishing it out to the No. 3 monkey (me)! As Ed commented to me after reading Dawkins' comment, "What does he think--that you slipped me a Mickey?"
If you still have the patience, let me make a few observations about this gem of a tantrum. First, why on earth would Dawkins title his response Genes Still Central ? Isn't he ever going to get over the fact that selfish genes have no bearing whatsoever on the group selection controversy?
Second, I trust that I have provided ample evidence that the original problem has provided the basis for defining group selection for everyone, including Dawkins and myself. There has been no redefining.
Third, when it comes to semantic confusion, you can't beat selfish gene theory. Genes are "the fundamental unit of selection" but this has no bearing on the "levels of selection" controversy. A gene might be selfish because it is selectively advantageous within groups, or it might be selfish because it evolves in the total population all things considered. Individuals might be perfected "vehicles" of selection now, but we also need to use the term "vehicle" to explain how such perfection evolved. This is how the simplicity of the original problem has turned into a terminological quagmire.
Dawkins continued his tantrum on his website after Ed and I quoted the passage in The Extended Phenotype where he abandons the replicator argument and takes up the vehicle argument:
The Wilson quotation from The Extended Phenotype is a ludicrous attempt to justify their lying statement that I "eventually" acknowledged an earlier error. For one thing, The Extended Phenotype was published way back in 1982, which makes nonsense of Wilson's "eventually". But more important, the point I was making in 1982 (and would make again now) was a general one about the important distinction between replicators and vehicles...I was explaining that those models of group selection that had been proposed were vehicle models not replicator models. I was not for a moment suggesting that I accepted those models as valid. They were (and are) invalid vehicle models, as opposed to invalid replicator models.
There you have it from Dawkins himself. The word "eventually" is appropriate for the six-year period between 1976 and 1982, regardless of how much time has elapsed since then. Poor Richard is still trying to fend off the Indians with the butt end of his replicator gun ("genes still central") and vehicle gun ("invalid vehicle models"). If only Bill Hamilton was still alive to fight alongside and defend his brilliant ideas!
Fortunately, Bill Hamilton wrote plenty while he was still alive, showing that Richard Dawkins fights on alone.
To be continued.