Saturday 21 December 2013

Universal Darwinism and the origin of life

One of the more coherent critiques of universal Darwinism I am aware of comes in the first part of the book Genetic Takeover: And the Mineral Origins of Life by A. G. Cairns-Smith. The author argues in some detail that there's no such thing as "prebiotic evolution", or "chemical evolution" - and the origin of life represented the dawn of the era of adaptation. He rejected the idea that you could draw on the concept of adaptation before the first self-reproducing agent existed.

We now know that this idea is wrong. There was copying with variation and selection before the origin of life. Evolutionary theory applies to a variety of non-living systems that preceded the first living things. The concept of "adaptation" also applies to such systems.

The rest of the thesis in this book seems little-affected by these more recent developments. Crystals still look as though they are the most likely candidate substrate for the first living things. The idea of a genetic takeover still seems to be highly significant.

Probably, universal Darwinism makes the probability of the origin of life seem larger - since invoking adaptation before the origin provides new paths and mechanisms via which life could arise.. However our main evidence relating to the likelihood of life's origin still consists of observations about its history on the planet and astronomical observations of other worlds - rather than arguments from physics or chemistry. So perhaps this doesn't make much difference.

However, universal Darwinism might help to illuminate possible pathways towards the origin.

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