One of the most important scientific debates that has occurred and is occurring in the world today is a debate within the community of evolutionary biologists as to whether there is such a thing as 'group selection'. On one side, we have evolutionary biologists like Richard Dawkins, Steven Pinker, and Bret Weinstein, all credentialed members of the Intellectual Dark Web, who denounce group selection biologists, proclaiming, sometimes vehemently, not only that there is no such thing as group selection but that there is a consensus among evolutionary biologists that that idea of group selection is bad science, heretical, and that this consensus has existed since at least the 'seventies. On the other side, we have biologists such as David Sloan Wilson, who argue that group selection is a real force acting on living beings (to use a loose metaphor). Wilson invented a new model, which he presented to the world in 2010 I believe, called 'multi-level selection', proposing that group selection can occur if there is competition between different groups within a species. Despite appearances to the contrary, there is no consensus among evolutionary biologists that group selection is wrong– it just so happens that the opponents of this 'heretical' idea are more visible than its advocates and that the gatekeepers in charge of scientific journals, knowing a little but not a lot about evolutionary biology, view use of the term 'group selection' as verboten, forcing biologists who are sympathetic to Wilson's ideas to employ alternative terminology. In tonight's post, I wish to discuss a concept closely related to group selection known as 'kin selection'. I wish to show that the theories advanced by Dawkins et al, when combined with the idea of 'kin selection', lead to a logically incoherent conclusion. This might make me a disciple of the 'group selection' model but I will postpone a declaration of fidelity to one side or the other until I have finished thinking these issues through.
What is group selection? Group selection occurs when organisms behave in ways that benefit the group to which they belong without significant benefit to themselves; in the long term, this helps the group compete against rival groups of the same species, causing the group to grow and fission into other groups. These behaviours include cooperative behaviours, in which individuals work together on common projects, for instance the way beavers cooperate to build dams. These behaviours also include altruistic behaviours in which an individual helps others within its group at a cost to itself. Group selection, it is argued, can only occur in species that live in groups; animals that don't, that disperse, such as most birds, don't undergo group selective pressure. Of course, humans are obvious examples of organisms that behave cooperatively and sometimes altruistically, but examples of such behaviours reoccur throughout the animal kingdom. This leads to the idea of an 'altruism gene'. The apparent problem with the idea of an 'altruism gene', as was pointed out in the 'sixties, is that, in a population containing both altruists and non-altruists, the non-altruists will outcompete the altruists (because they reap the benefits of others' altruism without paying any cost), and eventually the whole population will become non-altruistic. When this argument was first put forward in the 'sixties, it was seen as the clincher that killed group selection theory. The modern rebuttal of this argument, however, is that the scenario invoked doesn't consider competition between groups. Wilson argues that if inter-group competition is greater than intra-group competition altruism can win. Consider prehistoric humans. It is reasonable to suppose that, in our hunter-gatherer days, we lived in tribes of say a dozen to fifty people, and that different tribes fought against each other for resources. A tribe that could behave cooperatively, a tribe in which some members behaved altruistically towards other members of the same tribe, would win out in the fight between tribes, and so we can easily imagine the growth and spread of an altruism gene arising from the success of altruistic tribes.
Presented this way, group selection theory seems quite reasonable. But many evolutionary biologists, such as Bret Weinstein, loathe it. One reason for this is the astounding success of the book The Selfish Gene by Richard Dawkins. The theory he popularised, known as the gene-centred view of evolution or selfish gene theory, propounds that we should look at evolution from the perspective of genes: organisms are vehicles for their genetic material, designed to survive and create as many genetic replicas of themselves as they possibly can. Individual organisms are inherently selfish – in fact, individual genes can themselves almost be described as selfish. If we accept the paradigm presented by Dawkins and his followers, we need to prove that somehow apparently cooperative and altruistic behaviours arise somehow out of self-interest, that these behaviours somehow serve the interest of an individual's DNA. Dawkins and his followers have presented several different hypotheses concerning morality that ostensibly do away with any need for group selection or an altruism gene. The three most important moral mechanisms they suggest are reciprocal altruism, indirect reciprocity, and kin selection, and the most important of these three is kin selection. It is kin selection I shall focus on in this post.
An idea basically equivalent to 'kin selection' is 'inclusive fitness', a concept introduced to the world by W.D. Hamilton in 1964. Hamilton argued that an organism will seek to help and support all other organisms who share a significant portion of its DNA. A mother will help and support her offspring because they have 50% of her genes. An organism will help its siblings because they share (on average) 50% of its DNA. An organism will help its nephew or nieces because they share (on average) 25% of its DNA and a cousin because they share (on average) 12.5% of its DNA. An organism will help those related to it, its kin, because this is an indirect way to enable its own genetic material to survive into the future. Seen this way, kin selection also seems reasonable, but there are a number of significant problems with it, as I shall discuss.
We can start to see the problems with the kin selection hypothesis if we recognise that kin selection must follow from kin selecting behaviour and that this behaviour (by evolutionary biologists' own arguments) must be genetic. There must be a 'kin selecting allele''. If a woman is born who lacks the kin selecting allele, she will neglect and ignore her offspring, who will fail to survive past infancy, and so her lack of a kin selecting allele will not survive her. Logically, all humans must have a kin selecting allele. But this gene is also a selfish gene. And if all humans have the kin selecting gene, it is in that gene's interest for individuals to act altruistically with all other humans, regardless of how closely related they are. Combining selfish-gene theory with kin selection paradoxically leads to the evaporation of the concept of 'kin'. Dawkins is wrong, QED.
A second even more damning objection to the concept of 'inclusive fitness' is that, if it were true, logically, organisms would always mate with close kin. If I marry my sister our children would have, on average, 75% of my DNA; if I wish to ensure that I get as much of my DNA into the future as I possibly can, I would mate with those others around me who have the most exact copies of my genes. But this does not happen in the real world. I myself, although I am Caucasian, often imagine having sex with black women and asian women, even though they are only related to me very, very distantly indeed. There is an argument that humans and other animals seek out sexual partners who differ from us in important respects because this increases the likelihood that our offspring will survive and prosper. I may be weakly and anaemic but, rather than seek out another weakly, anaemic individual to reproduce with (and thus ensure that my weakly, anaemic genes pass on into the future), I instead look for a healthy, hale sexual partner to ensure that my offspring will have the best chance of succeeding they possibly can. If this argument is correct, an organism is driven to ensure it has as many offspring as it can regardless of how much genetic material its offspring have. Evolution takes place at the level of the individual, rather than the gene. Hamilton and Dawkins are wrong, QED.
There is a third objection to the concept of 'inclusive fitness'. When I presented the concept above, I said that an organism shares (on average) 50% of its DNA with its siblings. But this incorrect. Rather, I share over 99.9% of my DNA with my brother. In fact, I share over 99.9% of my DNA with all other humans. Yes, there are slight variations between humans (you might have blue eyes while I have hazel eyes) but, in aggregate, you and I are almost genetically identical. If there is an altruism allele, an allele which encourages an organism to help those who have much of the same genes, humans should help all other humans. We can go even further. A chimpanzee has 99% of the same DNA as a human, and a pig (according to a little research I carried out just now) is 84% similar at the genetic level to a human. Even bananas carry 50% of the same DNA as humans do. So, if inclusive fitness is a meaningful concept, humans should be driven to help individuals of other species because, in a sense, these other organisms are also related to us. Again, combining selfish-gene theory with kin selection paradoxical leads to the evaporation of the concept of 'kin'. Dawkins is wrong, QED.
The first and third objection to the concept of 'kin selection' I have raised in this post are roughly equivalent. If individual genes are selfish, individual organisms should all be universally altruistic because the other organisms they encounter, most especially those of the same species, all carry the same kin selecting allele and are almost genetically identical. Inclusive fitness leads to a paradox. The concept of 'inclusive fitness' developed within the same matrix, the same paradigm, as Dawkin's selfish-gene theory (although Hamilton's coinage of the term predated The Selfish Gene), but this paradigm is incoherent, collapses under the weight of its own internal contradictions. I have only discussed kin selection in this post but the two other proposed mechanisms for reconciling cooperative and altruistic behaviour with selfish-gene theory, reciprocal altruism and indirect reciprocity, I believe can also be shown to be untenable. Evolution takes place principally at the level of the individual organism rather than the gene. And it is reasonable to hypothesise that if selection occurs at the level of the individual as well as the gene, it could also occur at the level of the group. The picture I drew earlier of hunter-gatherer tribes competing with each other during prehistory, an inter-group competition that encouraged the emergence and propagation of altruism alleles, is sufficient explanation for morality among humans today, even though tribes had become villages, then towns, then city states, then nation states, and then have finally coalesced with each other totally to become the global community we live in today. The allele remains, even though between-group competition has vanished, either because evolution hasn't had time to weed it out or because it still serves a function in the present. I guess that, insofar as I myself am an evolutionary biologists, I am in the group selection camp, although I regard the debate between group selectionists and those opposed to them as diverting attention away from the fundamental question of whether evolutionary biology is itself correct or not. Just as evolutionary biology cannot explain homosexuality, there are many other features of human society it cannot explain, such as our appreciation of music and the reason we dream. Evolutionary psychology is seductive because it promises to explain everything, all human nature and the meaning of life – if one rejects it, what can one replace it with? Nevertheless, I feel that we need better answers.
At the beginning of this post, I mentioned Bret Weinstein. Wilson suggested a little while ago that Weinstein's views on the evolution of religion made him a group selectionist and this profoundly upset Weinstein. It was as if Wilson had called him a flat-earther. Bret's reaction is viewable on Youtube. I also recommend an essay by Wilson called "What Bret Weinstein Gets Wrong About Group Selection" which can be found on the Internet under that title. Apparently, Wilson has challenged Weinstein to a public debate about group selection. If Bret ever reads this post, I would like to recommend to him that he takes up Wilson's challenge. An honest debate about this issue could only be good for the world, and I for one would watch it.
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