Friday, 8 February 2008

Design or Apparent Design?

It’s my intention to debate the issues, not personalities; but as Richard Dawkins is such a popular advocate of evolution, I’m going to start by referring to some of the things he says; partly, because I agree with some of them.

In particular, I agree with him that the biological world looks designed, but that the subjective perception of design in itself is not conclusive. In The Blind Watchmaker (Ch.2) he calls this the Argument from Personal Incredulity - e.g. ‘I don’t see how something as beautiful / complicated or whatever as ... could have evolved’. As he says, there’s not much point in saying that something-or-other could not have arisen by chance, because no-one is seriously suggesting that a mammal, flower, or even bacterium has arisen spontaneously by chance.

We need to fully take on board the non-chance process of natural selection and its potential for producing a very unlikely end-product through a long series of small stages where each offers a small advantage over its predecessor. As he puts it in God Delusion (p 121, my emphasis) :

What is it that makes natural selection succeed as a solution to the problem of improbability, where chance and design both fail at the starting gate? The answer is that natural selection is a cumulative process, which breaks the improbability up into small pieces. Each of the small pieces is slightly improbable, but not prohibitively so.

But it seems to me that he is so taken with the elegance of the idea of evolution that he assumes it must be true and does not actually expose it to scrutiny. That last sentence which I emphasised is merely asserted, never substantiated or even scrutinised. He says we should examine the issue objectively, but doesn’t practise what he preaches!

I have also read Dawkins’ The Blind Watchmaker and Climbing Mount Improbable, both of which extol the power of cumulative natural selection, yet neither examines the crucial issue of the likelihood of occurrence of the variations on which natural selection can act. Despite his comments about breaking down immense improbabilities into smaller steps, nowhere is there any attempt to quantify the probability of those steps. In discussing the possible evolution of the eye (Watchmaker, Ch 4) he assumes that it can be broken down into infinitesimally small steps (in order to improve their probability); but this is not correct because of the discrete nature of genes.

Bertrand Russell said:

This [design] argument has no formal logical defect; its premises are empirical and its conclusion professes to be reached in accordance with the usual canons of empirical inference. The question whether it is to be accepted or not turns, therefore, not on general metaphysical questions, but on comparatively detailed considerations.

I agree, and I sought to examine the theory of evolution in the necessary detail in my Evolution under the microscope. But Dawkins never examines it in detail; he merely relies on the elegance of the theory, and polemic (and, sadly, ridicule).

Design or Apparent Design? - the answer is in the detail.


d0uglas said...


it looks like you abandoned your blog after one posting, which is a pity. I'm currently reeading your 'Evolution under the microscope' book and really enjoying it. Am neither pro-evolution or against, just an interested observer in the debate. I am surprised however that you don't appear to have had a storm of angry responses to your ideas - or maybe you have, only they're not on the internet??

also you first published 7 or 8 years ago - would you say the arguments have moved on at all? if so, how and do you intend to update the world!?

excellent book anyway,


Nigel Timperley

David Swift said...

Thanks for your comment, and sorry it's taken so long to publish it. I'll respond in another post - soon (honest!).

David Swift said...


Sorry for delay - it’s just that I need to put earning a living first! But Easter w/e is a chance to catch up with other things.


Llamamom said...

I believe the math is correct if we say that "impossible" divided by "infinity" equals "still impossible." Dividing it into smaller pieces doesn't make it any more likely. I'm just sayin'.

Andrew Chapman said...

It's not only genes that have a discrete nature. There are discontinuities in functional systems also. It is sometimes the engineers who point these out - Stuart Burgess on the knee joint, Andy Macintosh on the respiratory system of birds. An elbow joint is made one way, with as I remember a simple hinge. A knee has a four-bar hinge, with two ligaments that cross each other.

Mammalian lungs have two-way air flow: breathe in breathe out. Bird lungs are unidirectional, even though the birds are breathing in and out of their trachea. This is accomplished with storage sacs (my term) which hold fresh air to then go into the lungs while the bird is breathing out.

In both these cases, I suspect that there is a real design discontinuity, so that it would be impossible to have something half way between one and the other. So for common descent one would need a creature with simple hinges in their lower or hind limbs giving birth to one with four-bar hinges in these limbs. Needless to say, it all has to be very precise with the right curvature in the bones that roll against each other, the ligaments formed and attached in the right places, and no doubt all sorts of nerves and brain connections to make it all work.