Monday, 15 June 2015

The edge of evolution

The domain of Darwinian evolution has expanded dramatically over the last 150 years. Darwinian evolutionary theory is now frequently applied to cultural evolution, the development of individuals and individual learning. More speculative extensions of Darwinism include ones that cover quantum physics, complex adaptive systems, cosmological natural selection and observation selection effects.

It is natural for observers of this expansion to ask: how far can the Darwinism go? Where is the the edge of evolutionary theory? What are the limits of Darwinism?

The questions relating to "Darwinism" might be criticized as being a bit vague - but we can replace these with similar questions about the domain of concepts such as fitness selection and adaptation - and have some more rigorous questions that more people are likely to be able to form a consensus about.

I think that the lesson of history is that the edge of evolution is farther out than we think. People are inclined to say that the edge of Darwinism lies at the outer edge of their personal understanding of it. However, we can see historically that Darwinism has repeatedly pushed into new domains, covering new phenomena.

Another possible position is that there's no real "edge" - instead evolutionary theory gradually breaks down as more and of its axioms are progressively broken. I think that it is clear that there's some truth to this perspective. However, evolutionary theory is fairly simple - and there aren't very many axioms to break. Nonetheless, we should not necessarily expect to find a single precipice at the edge of evolution - but rather a gradual disintegration in the form of some steps or a slope. This complicates the issue - but doesn't fundamentally alter the problem.

To finish this article, I have a characterization of where I think the edge of evolution is to offer. I think evolutionary theory applies to macroscopically irreversible systems. This gives it roughly the same domain as maximum entropy thermodynamics - which I claim it is very similar to. Part of the intuition behind this involves the link between selection (from evolutionary theory) and destruction (which leads to many macroscopic entropy increases).

This relationship is probably wrong in detail. There's nothing in evolutionary theory that forbids its application to macroscopic reversible systems. Selection need not necessarily be linked to destruction. However, this is the best, short characterization of the edge of evolution that I have. Without it, I am reduced to offering a laundry list of phenomena that I think that evolutionary theory applies to.

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