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Pre-Adaptation: In Evolutionary Explanations, Too Much Serendipity


Who is the author of the following statement?

In contrast [to trait loss], the gain of genetically complex traits appears harder, in that it requires the deployment of multiple gene products in a coordinated spatial and temporal manner. Obviously, this is unlikely to happen in a single step, because it requires potentially numerous changes at multiple loci.

If you guessed this was written by an advocate of intelligent design, such as Michael Behe describing irreducibly complex structures, you were wrong. It was evolutionist Sean Carroll and co-workers in a 2007 PNAS paper.

When a design person says it, it is heresy. When an evolutionist says it, it is the stuff of good solid scientific research.

The difference is the design person assumes a realist view (the genetically complex trait evinces design) whereas the evolutionist assumes an anti-realist view (in spite of all indications, the genetically complex trait must have arisen by blind causes).

To support their position, evolutionists often appeal to a pre-adaptation argument. This argument claims that the various sub-components (gene products, etc.), needed for the genetically complex trait, were each needed for some other function. Therefore, they evolved individually and independently, only later to serendipitously fit together perfectly and, in so doing, form a new structure with a new function that just happened to be needed. As Richard Dawkins once put it:

The bombardier beetle’s ancestors simply pressed into different service chemicals that already happened to be lying around. That’s often how evolution works.

The problem, of course, is that this is not realistic. To think that each and every one of the seemingly unending, thousands and thousands, of genetically complex traits just happened to luckily arise from parts that just happened to be lying around, is to make one’s theory dependent on too much serendipity.

Photo: A bombardier beetle, by Patrick Coin [CC BY-SA 2.5], via Wikimedia Commons.

Cross-posted at Darwin’s God.