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From: Oliver Morton
This is apropos of almost nothing, but I thought some people might be interested. A while back Jaron Lanier referred in EDGE to the "spectrum" of views on evolution, and the amount of debate and ill will seen around the place definitely suggests polarisation and opposition. But a spectrum is normally taken as one dimensional, and for a while it has seemed to me that positions in the evolution debates are not strung out along a line (no more than political debates are really well characterised by a single left--right spectrum). A better analogy (in the sense of more functional, I'm afraid, rather than more elegant) is to a simple phase space like the one mineralogy students learn to use when thinking about feldspars. Feldspars are minerals made of aluminium, silicon, oxygen and X; they make up most of the earth's crust. There are three extreme positions in the feldspar world; anorthite, where X is pure calcium (CaAl2Si2O8); albite, which requires only sodium, (NaAlSi3O8); and orthoclase, the most potassium rich (KAlSi3O8). The differentiating X elements, however, can be mixed and matched, so there are all sorts of combinations available. This is visualised by means of a triangle with the endmembers at the vertices. Plagioclase feldspars sit along the albite/anorthite side, differentiated by the ration of calcium to sodium; alkali feldspars are ranged along the albite/orthoclase side.
The point of all this is that there are three endmember minerals in the world of evolution, or at least in popular debates about it: Gouldspar, Dawkinsite and Goodwinclase. In Gouldspar, the role of the historical, contingent and conjunctural is maximised. In Dawkinsite the system is saturated with adaptation. In Goodwinclase, the role of structural form in and of itself takes pride of place. Between these there is a variety of different possible mixed positions, acknowledging a role for, say, history and structure, while being mainly adaptationist. I suspect that all the men after whom I named the minerals might protest that their views are exactly such complex amalgams. But these positions would be pretty close to the corners of the triangle.
This may seem a very tedious way of dressing up the obvious, but I find that it helps to explain why debates on evolution roll on (if in a jerky way - that's the nature of rolling triangles). It's because there is more than one way to be opposed to any of the end members. People whose views are completely incompatible can come together in their disagreement with a third party; two men in a pub in Oxford can join in heaping scorn on a professor in a far-distant Cambridge in good conscience, even though the pair of them are as far apart along one side of the triangle as each of them is from the object of their discussion along one of the other two sides.
Well, that's about it. Ideas from others about what spaces within the triangle are untenable (are there tenable positions that correspond to a half and half mixture of Gouldspar and Goodwinclase with no redeeming Dawkinsite, for example?) and which are occupied (where does Stu Kauffman fit?) would naturally be welcome, as would other ways of looking at the issue, the more baroque the better.
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