HADD, adaptationism and the teleological naturalist

As human beings, we tend to want to know why things exist, and we assume that the purpose they serve is linked to the story of their origin. Human tools are created to function for a specific purpose and when we see functional things elsewhere (such as in biology), we tend to assume they exist in some sense because of their purpose as well.

This was highlighted for me in a recent walk in the Waitakeres, when a friend asked what the purpose of the barbs on a type of grass seed is (other than for vast quantities of them to get stuck in the leg hair of male human beings). It made perfect sense to assume that such a structure had a function and a purpose. Evolutionarily it makes sense to ask too – sometimes; in other cases, I think that on a naturalistic evolutionary account we should simply accept that stuff just happened to turn out that way, either through accident or through constraints imposed by pre-existing biological structures and processes.

This widespread search for purpose and preference for purposeful answers may itself be explained in part by reference to ‘HADD’, a hyper-sensitive agency detector device; a module (or set of modules) in the brain, which postulates agency on receipt of various kinds of input. An example of this is young children’s documented preference for teleological explanations of even natural features such as the pointyness of rocks – “so that animals can scratch themselves on them” is preferred as an explanation for this feature, over against “because stuff piled up over time to make them pointy” (or words to that effect). This kind of finding from psychological experiments is very well explained in Justin Barrett’s book “Born Believers”, that I’ve referred to before.

Now, it seems to me, that the ‘adaptationist programme’ which is quite popular in evolutionary biology – at least amongst popularisers such as Dawkins and Dennett, is a highly teleological one; albeit an attempt at a naturalised teleology. For the hard-core adaptationist, every (or virtually every) feature of organisms is an evolutionary adaptation and as such has an evolutionary purpose. The blossoming of evolutionary psychology or ‘evo-psych’ in recent decades is a great example of this penchant towards adaptationism amongst many scientists and pseudo-scientists.

If this suite of explanations are teleological and HADD turns out to be accepted as an explanation of other dispositions towards teleology (as in the case of religion), then much of the motivation for the adaptationist programme might well also be explicable by way of this ‘unreliable’ cognitive feature. But then, is adaptationism itself ripe for evolutionary debunking? (I may’ve said elsewhere, I think more fundamentally the underpinnings of scientific realism are themselves ripe for such debunking, but that’s a future project for me).

You may be wondering why I care about this. In short, simply because I find it interesting. Belief in God is unlikely to gain or lose much support whatever the relationship between HADD and adaptationism is – though, personally I can imagine (in a very loosely sketched out way) a teleological story working better or easier where adaptation is not the only driving force behind evolutionary innovation (by which I mean the creation of novelties, without necessarily implying any teleology in the immediate process of change) – but exploring this is perhaps another project for another time. I am intrigued by the idea of exaptation and evolutionary anticipation (heretical phrase though that is!) in any case.

P.S. as with a number of the philosophical or semi-philosophical posts I’ve made over the last couple of months, I think there is something, a small germ, in what I’ve said which is quite important and perhaps even novel here. So, please don’t steal my ideas and please do talk with me about them if they’re of interest. 🙂


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