Tuesday, April 28, 2009

Cranes vs. Skyhooks: Metaphors for Evolutionary Mechanisms

The Crane Metaphor for Evolutionary Mechanisms and a New Species!

Recently, Richard Dawkins, noted evolutionist and critic of religion, spoke before a gathering of American atheists to discuss various topics related to what he sees as the tension between scientific and religious thought. While unsurprisingly, the vast majority of his presentation dealt with the response to religious apologetics, he did make several interesting comments concerning evolution and the origin of life. Specifically, Dawkins raises the possibility of life’s having been seeded by a superior civilization, however, he argues, such a superior civilization “would have to evolved by some form of gradual process – probably in my opinion, rather similar to Darwinian natural selection – but if not Darwinian natural selection some kind of ‘crane’… rather than skyhook…” This seems to me to be a good metaphor for distinguishing between Darwinian evolutionary theory (and similarly naturalistic evolutionary theories) and the sort of pseudo-evolutionary theory described by C.S. Lewis in my previous post reviewing C.S. Lewis’ Mere Christianity.

This characterization of Darwinian natural selection as a crane and not a skyhook, which Dawkins appropriates from Daniel Dennett seems like an instructive metaphor for the following reasons: namely, that (a) evolution and natural selection are distinct, and that the latter is a mechanism for the former; and (b) the “crane” of evolution need not be limited to the single crane of Darwinian natural selection, but can accommodate other evolutionary theories (punctuated equilibrium, etc.). Interestingly, Stephen Jay Gould has taken issue with this latter feature of the metaphor, arguing that Dawkins/Dennett’s use of the metaphor is overly restrictive, since they attempt to use it to eliminate non-Darwinian evolutionary mechanisms – namely, Gould’s own aforementioned evolutionary mechanism – however, this charge seems spurious in light of Dawkin’s non-exclusive use of the metaphor.

A full recording of Dawkin’s presentation is available here on Dawkins’ website.

In other news, paleontologists have discovered the remains of a new form of primitive marine mammal, which they believe to be the missing link between seals and terrestrial mammals. The species has been named Puijila darwini or "Darwin's young marine mammal", in honor of Darwin.

Ben Picozzi

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