Saturday, 29 December 2012

Tim Tyler: Williams, Plan and Purpose in Nature (review)

Tim Tyler: Williams, Plan and Purpose in Nature (review)


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

Plan and Purpose in Nature: The Limits of Darwinian Evolution by George C Williams.

George Williams is an expert in Darwinian evolution, and this book is an attempt to condense his knowledge down into a format which is easily digested by those new to the field. It is very readable and entertaining book.

It covers basic issues in evolutionary biology, particularly adaptationism, the unit of selection, sexual reproduction, senescence and medicine.

Williams embraces the term "The adaptationist program" - saying he almost selected it as the title of his book. This phrase originated with Gould and Lewontin - and was intended as a term of derision. No doubt Williams is making a point by using the term, but I would have preferred that adaptation enthusiasts left it alone - making it harder for critics to point at instances of the alleged phenomenon.

The book was published in 1996 - and I thought it was interesting to see what had changed since then. Williams offered an explanation for sexual reproduction that invokes generating diversity to help adapt to novel environments. For example plants like strawberries reproduce using runners and vegetative reproduction locally, but produce sexual seeds for transmission of offspring to a diverse range of remote environments. That is not a completely unreasonable explanation, but the modern way of putting it invokes parasites. If it wasn't for the need to evade parasites, the environment would often not change fast enough to favour sexual recombination. Williams does mention parasites, but they aren't the main feature. Another area where I noticed there were some oddities were in the chapter on senescence. The disposable soma theory and the antagonistic pleiotropy theory of aging are given without being named - and Williams emphasizes how senescence of living bodies is nothing like senescence of machinery - saying:

In thinking of senescence, the analogy to the wear and tear, or corrosion, or other process that ultimately causes an artificial device to fail is utterly misleading.

I think that the relationship here is close enough to not deserve being described as "utterly misleading". Indeed these days we have new modern theories of senescence - like "reliability theory" - that apply to both machinery and bodies, that highlight the relationship between senescence in both kinds of system.

The section about group selection has stood the test of time reasonably well. Williams says that most animal groups are not functionally organized, and that most groups are "just mobs of self-seeking individuals". That's true - though these days people might take more care to mention the possibility of cooperation with kin - i.e. genetic selfishness, not individual selfishness.

The section about medicine is welcome as well. However, while Darwinian medicine sounds nice, we seem firmly embedded in the era of "drug company" medicine, with little sign of an end in sight.

At the end of the book there's a section on philosophical implications. Williams describes the product of natural selection as immoral. He says "although the biological creation process is evil it is also abysmally stupid". His example of the horrors of natural selection is infanticide by males, which he argues is natural and adaptive - though obviously infanticide by males is certainly not adaptive in many modern societies today - since it is likely to result in extended incarceration. Williams endorses Dawkins' proposed rebellion against the selfish replicators and responds to naturalistic moralities with condemnation. This is a common position these days, but human morality sits firmly in the domain of evolutionary theory, and if your theory of evolution doesn't explain it, you need to rethink it. I figure that evolutionary theory offers reasonable explanations of morality that we don't need to apologize for.

Anyway, this is still a fine book - though perhaps some learned readers might find it too simplistic.


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