why evolutionists shouldn’t be reductionists

An interesting thing I got from reading a phil bio book is that evolutionary explanations are problematic for the reductionist. It may not be a big deal, as I’ll try to explain later, but it is quite interesting (to me anyway).

The science of evolution describes current states of the biological world in terms of evolutionary processes occurring in the past – “no problem for the reductionist there surely”, you cry! “Just a collocation of atoms, sometimes taking on organismal forms in response to the vagaries of chance and necessity; what’s the problem?!”

The issue is that evolutionary explanation is in terms of “function” – evolution is said to select not for the particular arrangements of organic molecules in an organism’s future progeny per se, but rather for a particular function, i.e. a pattern of molecules oriented towards a particular (survival-conducive) goal. The nature of evolutionary explanation is that it deals in functions, in an orientation towards a goal, rather than in mere arrangement of particular atoms. So, there seem to me to be two problematic aspects – firstly the fact that the pattern selected for is replicated in future; the same pattern in different particular molecules. The pattern is ‘multiply realizable’, and I think this means that it cannot be described in terms of constituent parts (but I’m not sure …).  Secondly, the pattern is oriented towards a goal, the survival of the organism. This is more clearly problematic for the reductionist, as “survival of the organism” can be spelled out in a huge variety of possible scenarios when considered in terms of the arrangement of atoms.

Is this merely an explanatory deficiency of reductionism; is reductionism just a little (!) unwieldy when practiced strictly, so that scientists are forced to use convenient short-hand forms while knowing that deep down, the standard tools of physics are all a scientific purist would need? I don’t think so; if you’re a realist about evolutionary explanations, it seems to me that you are claiming a real role for ‘functions’ in science and the world, and these are not fully analysable in terms of their constituents, so provide a counter-example to reductionism.

Darwin’s tree of life – image from Wikipedia

… [there is more work to do here, including, in the long term, some exploration of what a ‘pattern’ is most plausibly actually constituted by – this will probably involve looking into the philosophy of mathematics & mind; we’ll see whether I get around to it. I also need to tidy up the distinction between reduction of explanations and reduction of things in the world.]

I’m well aware that one can be a non-reductionist materialist, and hold that there are natural laws above the level of mere physics, or such, without asserting the existence of something non-physical; in fact, this is the majority position amongst philosophers of science, as I understand. While I am no fan of reductionism, it is not, in a sense, ‘the real enemy’. However, the rejection of reductionism does open the door I think to interesting non-materialist possibilities and/or non-standard metaphysics. More on this as/if I work it out.


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