Defining Evolution

When I read the title of this piece (Theologians Lobby Successfully to Change Definition of Evolution | Cosmic Variance | Discover Magazine)I was prepared to get angry. But instead I am embarrassed on behalf of those who are complaining about the change (which happened more than ten years ago).

Apparently the US National Association of Biology Teachers was persuaded to delete the word “unsupervised” from the following statement:

The diversity of life on earth is the result of evolution: an unsupervised, impersonal, unpredictable and natural process of temporal descent with genetic modification that is affected by natural selection, chance, historical contingencies and changing environments.

Now apart from its awfulness as a bit of language this is indeed wrong on several counts.

Perhaps most importantly, it appears to deny the predictive capacity that is essential for a “scientific” theory. In fact, the theory of evolution does have some predictive capability (though albeit of a stochastic nature). So the unqualified use of  “unpredictable” must be inappropriate.

Also, although it does not require supervision or purpose, the theory of evolution makes no statement regarding their absence. So to include the word “unsupervised” was indeed just plain wrong.

This, of course, is the source of the problem. Some scientists, such as Jerry Coyne want to “characterize evolution and selection as processes lacking mind, purpose, or supervision”. Of these the first is unquestionable since a mind is a property of a thing or creature itself and so if one is not included in the theory then it doesn’t “have” one. But the other two are more problematic. Of these the last one is easiest to deal with. Since supervision of anything or process can be external to that thing or process and does not necessarily imply the capacity or will of the supervisor to intervene the fact that the theory does not require supervision and shows no evidence of intervention does not preclude its being watched over nonetheless. In fact it could be said that I am “supervising” it right now! As to purpose, since evolution presumably isn’t a conscious entity with an intent of its own this must refer to its having been set up (or resulting from something set up) for some purpose by a prior agent. There is of course nothing in evolution which requires such a purpose, but as with supervision, there is nothing which precludes it either. We may have no evidence of supervision or purpose but lack of observed evidence is not evidence for absence, and so to deny supervision and purpose is to take a religious position that is not required by the science. So it is odd to see Coyne’s position supported by Sean Carroll despite his apparent belief that “organizations that bill themselves as ‘centers for science education’ and ‘associations for science’ and ‘academies of science’ should not take stances on matters of religion.”

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