Tuesday, 14 August 2012

A critique of Richard Dawkins’ The Greatest Show on Earth: The evidence for evolution

5. Smoke and Mirrors - trying to obscure the challenge of embryology

As I said previously, it's evident that Dawkins realises the complexity of embryological development presents an insuperable challenge to an evolutionary origin; but, being committed to the evolutionary cause, he tries various diversionary tactics to dumb down that complexity.


First he goes to considerable lengths to argue that the popular portrayal of DNA being a blueprint is wrong. For example he says that, although a house can be built from a blueprint and a blueprint drawn from the house, it's not possible to deduce the DNA sequence from the form of the host body. Of course no-one is suggesting that DNA is a graphical representation, even in coded form, of the developed body; and this is so obvious that one might wonder why Dawkins takes the trouble to make the point. His reason is that, because it's obvious a blueprint must have a designer, he seems to think that by showing that DNA is not a blueprint he is showing that there is no need for its having a designer. As if the only way the input of a designer might be inferred is if they leave some sort of blueprint - which is obviously not the case.

DNA may not be comparable with a blueprint, but certainly it contains the information for developing an organism; so, quite apart from how that information is encoded, the important question is, How did that information originate?


He then turns to starlings to try to support his premiss that biology does not have a designer. Starling flocks may appear to act as a whole - perhaps resembling a troupe of ballet dancers; but, he emphasises, in the case of starlings there is no choreographer - each bird is merely acting individually (not independently, as it responds to those nearby). And so he extrapolates from this that there is no director behind the embryological development of organisms - he argues that each cell is merely following local rules.

To try to reinforce his argument, he describes how the behaviour of birds in a flock can be modelled mathematically, just by building in local rules for each bird to follow. But actually this serves to reinforce the point that, even with something like a flock of birds (whose behaviour is so much simpler than that of cells in a developing body) at bottom it rests on rules. Rules which, even in the case of his simple model, must but be conceived and formulated, coded into a computer programme, and then fed into a complex machine that can apply the rules for all the individuals - each stage requiring intelligence.

I shall explain later why his flock analogy falls woefully short of embryological development anyway.


This is taken even further with his other ‘analogy for development’ - origami. Dawkins accepts that, even though not a blueprint, DNA does contain the instructions for growing an organism. And, because embryological development includes (among many other things) the folding of tissues, he compares this with origami - using the well-known construction of a junk as an example.

Even at a very superficial level, this analogy falls well short of illustrating his evolutionary premiss, because he would have to assume that an origami junk had arisen simply through random foldings of randomly shaped pieces of paper - which of course is totally wrong. On the contrary, an artisan will first have conceived of the end product and then devised a way of constructing it - with the desired object in mind as he does so.

But the really amazing thing about embryological development is the way in which all of the development takes place internally - there is no external agent doing the folding etc. Dawkins acknowledges the importance of self-assembly, but yet again thinks that by modelling the process with a computer he is explaining it away.

He wrongly says that the scientists in question have ‘deciphered’ the embryological process whereby tissues can fold (p229). They have not done this at all; all they have done is mimicked one aspect - and that in only two dimensions rather than three. But the key point, yet again, is that, even with this considerably simplified system, it requires formulation and programming of the rules, and then using a computer to implement them.

It’s all very well for Dawkins to argue that development proceeds through the implementation of local rules (and does not require a grand plan, but I will contest that next); but even the implantation of local rules requires considerable input of information. And none of his examples even attempts to explain whence or how that information is derived.

Thursday, 2 August 2012

A critique of Richard Dawkins’ The Greatest Show on Earth: The evidence for evolution - cont...

4. Half-truths about proteins

It is clear Richard Dawkins realises that the complexity of embryological development poses a serious challenge to the theory of evolution, so he goes out of his way to gloss over the realities. The cornerstone of his approach is to try to argue that embryological development proceeds simply through the natural operation of local rules i.e. without an overall plan that would need a designer. I will explain subsequently how his attempted sleight of hand doesn’t work. Meantime ...

Unfortunately (for him), he tries to build up his case with reference to the structure of proteins; but it is his undoing because exposing his half-truths here makes it all the easier to explain the fallacy of trying to apply a similar approach to embryological development. As he says, proteins comprise linear sequences of amino acids, which fold up into a 3-dimensional structure which is essential for their biological function.

Protein molecules, simply by following the laws of chemistry and thermodynamics, spontaneously and automatically twist themselves into precisely shaped three-dimensional configurations. ... Any given sequence of amino acids dictates a particular folding pattern. (p236)

What he fails to say is that, simply because of the laws of chemistry and thermodynamics (his local rules), the vast majority of amino acid sequences will not fold at all. By not acknowledging this, he gives the false impression (false, but no doubt deliberate, as he must surely know this) that most amino acid sequences will fold in this way. Whereas in fact very few do - Douglas Axe estimated that only about 1 in 10^77 sequences have the potential to fold (Estimating the prevalence of protein sequences adopting functional enzyme folds; J Mol Biol 341(5):1295

Dawkins mentions only the specificity of proteins in terms of their ability to selectively bind their substrates (compounds they act on). What he ignores is their active sites - the parts of the proteins that have just the right chemical groups (derived from the right amino acids) in just the right places in relation to the bound substrates so as to catalyse reaction between them. Needless to say, taking these features on board as well, further compounds the specificity required of the amino acid sequence for e.g. an enzyme, and hence reinforces the prohibitive improbability against their arising by chance.

Dawkins comments that at present we are able to predict how some amino acid sequences will fold; and quite likely we will be able to do this for all before too long. But that’s only one side of the coin. What’s required is to identify an amino acid sequence that will fold, and once folded will perform a required biological function. Thanks to increased computing power and some ingenious programming, I expect that one day we will be able to design proteins to fold in a particular way, and maybe perform a particular function. But that will serve only to reinforce the case that functional proteins require a designer.

The nonsense that proponents of evolution would have us believe is that biologically active proteins, with their highly specific and hence improbable sequences, could arise by chance. Dawkins of course rolls out the usual evolutionary article of faith that complex proteins evolved from shorter/simpler precursors. But, as discussed more fully in my book, there are substantial objections to such a scenario.

  1. First is the question of folding. The forces between the packed amino acids (Dawkins’ local rules) that hold a protein in its folded state are so weak that there needs to be many amino acids involved, typically requiring a protein to be at least 70 amino acids long (see Protein structure and function by Jack Kyte) So it’s utter nonsense to suggest as some textbooks do, and Dawkins would have us believe, that proteins could have started off with just a handful of amino acids.
  2. Second is that key amino acids, such as those contributing to the active site, are generally scattered throughout the linear sequence of the protein, and are brought together only once the protein is folded. If proteins had evolved from short sequences, one would have thought that at least these critical amino acids (which necessarily would need to have been close together in a short protein) would still be grouped together; because to disperse them during the course of subsequent evolution would require constant restructuring of the protein.

It’s all very well for Dawkins to argue that proteins fold merely through the operation of local rules / natural forces. But what he fails to acknowledge is that operation of those rules results in something useful only if the underlying components are right - so far as proteins are concerned, that they have the right amino acid sequence. And the evidence clearly shows that natural selection acting on random mutations could not generate such sequences. Evolutionists merely cling to this hope as a drowning man clings to a straw.