Thursday, January 05, 2006
Contingency and Natural Form in Biology
Another idea is that of platonic forms. The idea is that biological systems follow a form that is built-in to nature. Denton's paper, The Protein Folds as Platonic Forms: New Support for the Pre-Darwinian Conception of Evolution by Natural Law, points out one aspect by which it appears that the platonic concept might be true -- the rules of protein folding.
The thesis is, despite the huge number of total proteins that we know about (hundreds of thousands or more), there is really only about 1,000 folding patterns that all of these proteins fall into. In addition, in these folds, the structures are stable -- they do not require outside help to keep them from being damaged through minor perterbations.
Thus, the protein folds cannot themselves be described through contingent language (well, not quite, but we'll get to that in a minute). The proteins folding patterns are part of the laws of physics, and are not necessarily encoded anywhere. They are "platonic forms" in that they are ahistorical, and arise by necessity anywhere that a protein-based system would be used.
The discovery of protein folds following platonic forms leads naturally into asking what other sort platonic forms might be available. I have heard that D'Arcy Thompson's work, On Growth and Form, talks about the laws of form that living things follow. While I own this work, I have not yet had the time to go through it. Likewise, I think that Following Form and Function has a great deal of material about this, but again, I have not read it.
So how does this affect creationary theory? Evolutionary theory? It doesn't affect either one very much, per se. The fact that we don't see life forming spontaneously today indicates that while certain parts of life may be governed by platonic forms, life itself is still very much contingent (and theistic philosophers will also note that the laws of physics by which the forms come about are likewise contingent, but that is really outside the present discussion). Creationists are fully within their rights to see that the God who designed physics also designed creatures to make the best use of it, and designed physics in such a way as to support life.
It does, however, have some effect on some of the arguments that are used against creationists about homology. If it may be allowed that some parts of organismal form is not contingent, but in fact one of only a few possible complete arrangements, then homology, in addition to being part of a "common design" as is often articulated, may be the result of there being only a finite number of organismal forms available. So, in addition to homology being a common design patter, homology may be also be an intrinsic property of physics, having nothing at all to do with an organism's history. Note that this is not evidence against evolution per se, only showing another way that the evidence used against creationists does not necessarily imply what the evolutionists say it implies.
Anyway, the point of all of this is to spur our thinking in other directions. That we need not think strictly in terms of contingent features, but also let ourselves think of the forms that may be bound up with the laws of physics that are controlling organismal form.
One thing that the paper pointed out that was really interesting is that many biologists throughout history have actually viewed function as secondary to form -- that function is a secondary adaptation to a natural form. An interesting viewpoint, and one that we can probably learn a lot from.