Wednesday, 5 October 2011

Natural selection as a metaphysical system

*

I may be missing something, but I have seldom (although not never) been troubled by the conflict of Christianity and evolution by natural selection - because when properly considered, natural selection is a set of metaphysical assumptions.

http://charltonteaching.blogspot.com/2011/08/natural-selection-and-me.html

*

By metaphysical I mean that these assumptions are (obviously) hierarchically above those of science; and therefore natural selection is not testable by science.

(At least not testable by the doing of science - since a meta-theory which constrains and guides scientific hypotheses and their testing cannot itself be subject to these tests).

This has almost always seemed very obvious to me.

*

Of course, when progress is being made within a metaphysical paradigm, and when one is an 'expert' in that paradigm, there is a very strong temptation to assume and to assert that the paradigm is universally true (and that therefore one is an expert in 'everything') - and I have fallen into this trap, from time to time.

*

As I see things, the theory of evolution by natural selection says something like the following:

"Let's see if we can devise explanations for adaptation (the specific functionality of living things) without assuming any purpose towards functionality - adaptiveness simply arising as a consequence of the un-directed variation in reproducing entities and the effects that such variation might plausibly have on reproduction."

That competitive selection processes acting on reproducing entities will tend to amplify those variations which reproduce the most effectively, is not really controversial - it is hard to imagine why this would not happen.

But the key metaphysical assumption is concerned with the raw material upon which selection operates - in other words the assumption that the variation is un-directed.

*

(It is worth mentioning that variation is not random for the simple reason that in biology nothing is random. Randomness is essentially a mathematical abstraction, although maybe it occurs is some bits of physics - at any rate there is no randomness in biology, although one can sometimes assume randomness as a simplifying approximation.)

*

It is the assumption of evolution by natural selection that the source of variation upon which selection operates is un-directed - or, at least, may be assumed to be un-directed in the specific instance under consideration - which is critical.

That the variation actually is un-directed is not subject to test - indeed it is often impossible to test the assumption.

Instead, the theory of natural selection simply says, in effect: "Let's assume that the variation (e.g. of genes, or of some other reproduction-affecting information such as epigenetic variation) is in this instance un-directed, and see if we can construct a scenario which results in the observed phenomena".

I cannot see anything intrinsically wrong with consciously making this assumption, and with proceeding to reason on the basis of this assumption; and this is what I do when wearing my cap as an evolutionary theorist.

*

But there surely cannot be any reason for assuming that un-directed variation is the only possible basis for that variation upon which selection works; and to make such an assumption of universality is wholly arbitrary.

*

(Indeed, one cannot even be sure that un-directed variation applies even in any one specific instance - the most that can be done is to point at the results of making this assumption: saying, in effect: "Look! when I make this assumption it all seems to fit together very neatly with this set of observations and experiments!" However, another and different assumption, might - whether now or in the future - prove to be equally or more impressive in its coherence and scope. And then what?...)

*

I do not feel a need to go further than this negative statement: that the assumption of un-directedness is a metaphysical assumption.

I think we can be absolutely clear and certain that there are no grounds whatsoever for assuming that un-directed variations (such as genetic mutations due to radiation or copying errors) are the only possible form of variation that can ever form the substrate of selection processes.

How on earth would one even go about proving such an assertion? Certainly Darwin didn't attempt it - he merely offered a new explanatory metaphysic, an alternative. And, at any rate, nobody ever has proved any such thing.

*

Yet attempts to put forward alternative possible directed sources of variation (such as divine creation, intelligent design, chaos and complexity theory, or morphogenetic fields) are not scientifically proveable as against natural selection - because they are alternative metaphysical assumptions.

No amount of observational or experimental evidence can count either for or against metaphysical theories - since metaphysics is hierarchically above science: metaphysical is a name given to the assumptions which constrain a particular science.

*

The problem is that modern culture has no idea what to do about evaluating metaphysical theories - and so keeps on trying to evaluate them scientifically...

But if not by science, then how should metaphysical theories be evaluated?

Ah - that is an almost lost art. The activity by which metaphysical systems are compared and evaluated is called philosophy, and it was invented by the ancient Greeks and perfected by Thomas Aquinas - but almost nobody practices it today...

*