Saturday, 15 December 2012

Tim Tyler: Wilson, Darwin's Cathedral (review)


Hi. I'm Tim Tyler, and this is a review of this book:

Darwin's Cathedral: Evolution, Religion, and the Nature of Society by David Sloan Wilson

This is a relatively early book by a scientist looking at religion. Religion is a messy subject, which only a few scientists have attempted to deal with. Wilson's thesis is that religion is functional, and that its associated benefits accrue to groups of humans. He compares religious communities to beehives - on the grounds that their members cooperate with each other much as members of a bee hive do.

What are we to make of David's thesis? Bees in hives cooperate because they are extremely close relatives - since they are all daughters of the same queen. However most humans in religious communities are not anywhere near as closely related. So, in terms of DNA genes, the relationship between religious communities and bee hives is pretty far fetched. However, religious communities also share their memes, and a reasonable fraction of their memes is shared between community members. In particular the memes associated with their religion are often present in the form of near-identical copies in different members of the same religious community. Cultural relatedness does not necessarily lead towards altruism between the hosts involved, but it can do so. Much depends on the nature of memes in question and the strength of the host's memetic immune system. Memes don't have a free ride in manipulating the behaviour of their host - since they must compete with the other memes in the host and the host's own DNA genes. However with large coadapted meme complexes many memes can gang up together in an attempt to influence their host by force of numbers. That's exactly what religious memes do - and they evidently do have considerable success in influencing their host's behaviour. So, a comparison with bees may have something to it - though memetic relatedness between humans from the same religious group is probably not as high as genetic relatedness between bees within hives.

Another of the ideas David advocates is that religion is "functional" - by which he seems to mean adaptive to humans or groups of humans. He contrasts this position with "religion as a byproduct" hypotheses, economic theories involving religion as a form of transaction with alleged supernatural agents and the idea of religion as selfish memes. I think most consider religion to frequently be adaptive to its hosts. Religious people typically have more kids than secularists, often quite a lot more. One of the insights into the subject from cultural evolution is that when talking about the adaptive function of some aspect of religion, the DNA genes of the hosts are not the only possible beneficiary - religious traditions may be treated as cultural symbionts which have adaptations that benefit themselves. Wilson acknowledges the possible viability of such hypotheses, but categorises them in such a way that they compete with his own preferred explanation. He categorises adaptive theories of religion into those that invoke benefits to individuals, those that invoke benefits to groups, and those that treat religion as a cultural parasite that often evolves at the expense of individuals and groups. However, real religions vary considerably in the extent to which the interests of their memes is aligned with the the interests of the DNA genes of their hosts. Those religions which are transmitted primarily vertically down the generations can be expected to have evolved to have interests aligned with those of their hosts. Cultural and organic evolution pulling in the same direction explains the cases where religious groups typically have many children. By contrast, evangelical religions depend less on vertical transmission with respect to their hosts, and spread virally even between unrelated hosts. Such religions can be expected to be less in tune with the interests of their host's DNA genes, and more inclined towards redirecting host reproductive resources into meme propagation via evangelism. They will tend to be nastier religions.

David's correctly identifies kin selection at work - though he classifies it as group selection. Since group selection and kin selection are now widely thought to be equivalent, this is a valid perspective. However he doesn't really identify it as a cultural phenomenon. Indeed he seems to identify cultural evolution with the idea of "demonic memes" that act as parasites on humans - and then largely ignores it. Instead he proposes human groups as the beneficiaries of selection on religions. This seems like a muddled way of looking at the situation to me. Instead, the humans genes are weakly kin-selected, the religious memes are strongly kin selected - and the genes and the memes coevolve in a symbiosis. The interests of the memes and genes are somewhat aligned - largely due to the component of vertical transmission of religious beliefs. I felt that David's treatment of the topic muddled together cultural and organic evolution.

It is possible to ask whether religion is adaptive without distinguishing between cultural and organic evolution. I compare this approach to asking whether smallpox is adaptive. Through much of human history, smallpox helped groups of humans with smallpox to obliterate other tribes of humans who lacked it. Evidently smallpox is an adaptive trait at the group level. While partly accurate, this analysis is unorthodox - and misses out much of interest about the relationship between the smallpox virus and its human hosts. David's explanation of religion is like this. He just says it is adaptive at the group level - without teasing apart the relationship between the cultural and organic components of the system involved.

David does display some understanding of cultural evolution in this book. He invokes Calvin and Plotkin's idea of "Darwin Machines", uses it to explain how the brain evolves in a Darwinian fashion and then goes on to explain that human culture evolves. The section near the start of the book about cultural evolution is quite reasonable - as far as it goes.

Memetics isn't the only rival theory which I felt David treated unsympathetically. He also contrasts his approach with the idea of religion as a by-product. While functional explanations and "by-product" explanations can be seen as being opposed, it is pretty evident that the various "by-product" theories of religion have a lot going for them. The "Hyperactive Agent Detection Device" idea, is correct, for example. "By-product" hypotheses explain quite a few aspects of religion. Also, some of the traits which religion is thought to be a "by-product" of are themselves adaptive traits - so "by-product" hardly means the same as "non-adaptive". I think we should accept many of the "by-product" hypotheses concerning religion - without necessarily granting them everything.

It would be nice to have a scientific understanding of religion, not least so we can build new and better religions that draw from the best parts of their historical practices while missing out their toxic elements. However to do that we need to understand which bits of religion are desirable and which are not. Some things are obvious: yoga and meditation are good while hellfire and the oppression of women are not. However with other practices, things are not so clear. Just saying that religions are adaptive doesn't really help to identify which are the useful practices.

At the end of the book, David explains that a grant from the Templeton foundation helped to finance the book. The Templeton foundation is famous for paying scientists to say nice things about religion. I expect this funding source will turn off some readers.

Studying religion seems like a dirty job for a scientist - but someone has to do it. David Sloane Wilson seems to be OK with the topic. However back in 2002, he seemed to be rather hampered by his preference for explanations based on group selection and his reluctance to conceptually separate out cultural and organic evolution. Also, alas, this book isn't terribly readable. I found the long section analysing Calvinism in the middle to be especially tedious. I recommend that those interested in David's work should read Evolution for Everyone first.


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