Friday, February 25, 2005

In Defence of Darwinism: The Ignorable Berlinski part 2


First, a few points on style
In an episode of The Simpsons, Homer has the following exchange with Lisa, after she announces her intention to become a vegetarian.
Homer: Are you saying you're never going to eat any animal again? What about bacon?
Lisa: No.
Homer: Ham?
Lisa: No.
Homer: Pork chops?
Lisa: Dad, those all come from the same animal!
Homer: Heh heh heh. Ooh, yeah, right, Lisa. A wonderful, maaagical animal.

You know how cringe-worthy it is when you're discussing something with someone who, to put it as politely as possible, isn't very bright, and after they run out of arguments they resort to clumsy sarcasm instead? Painful, isn’t it?

Reading Berlinski’s article “The Deniable Darwin”, which appeared in ‘Commentary’ magazine in 1996, is a bit like that. He hasn’t got all that much to say and he knows it, so he pads what should be a brief article of a few hundred words into a long and tedious tirade by adding reams of sarcastic purple prose.

(The most grating of these passages being his little coda designed to ‘mock’ the idea that random natural selection can create complexity, where he imagines a conversation with “Jorge Luis Borges one evening in a Buenos Aires café”: “I raise my eyebrows. Borges pauses to sip discreetly at the bitter coffee our waiter has placed in front of him, guiding his hands to the saucer.” And so on ad nauseam.)

All very well, and great fun for Berlinski I’m sure, but this bumf serves no purpose other than to obscure what little actual ‘argument’ he makes. Trim this fat to find the meat beneath, and the offerings are scrawny in the extreme.

The first five or so sections of the essay could be summarised thus:

1. The evidence for the Theory of Evolution is in some instances incomplete and open to more than one interpretation
2. Darwinists disagree with each other over certain things

Both true enough, but hardly earth-shattering. Of course you can interpret any evidence in different ways. The question is, which is the best explanation? Of course Darwinists disagree with each other about certain things. But they agree about some things, and those things are the content of the TofE which any opponent must address if he wants to undermine it.

Note that while Berlinski is held up as a leading light of the ‘Intelligent Design’ movement, none of these points are actually positive arguments FOR anything in particular. They’re just general attacks on darwinism.

The meat, such as it is, of his essay depends on the claim that darwinism’s account of ‘purely random’ mutation cannot account for the complexity and variety of life which we see in evolution and the natural world.

The Arguments
Berlinski argues for this in two ways, both of which appear in the sections “The Artificer of Design” and “The Head Monkey”.

(for this part of my article I am significantly indebted to H. Allen Orr, who is quoted by Berlinski as support, but who actually refutes ‘The Deniable Darwin’ in a letter to Commentary magazine)

The first argument, which I’ll call the ‘Language Jam Argument’, goes like this:

1) Darwinian evolution is based upon the notion of random mutation plus natural selection, at the level of DNA.
2) DNA is a discrete "alphabetic" language of A's, T's, G's, and C's that carries the code for all the phenotypes we find in organisms.
3) But random changes in languages, eg. English, creates gibberish.
Therefore, darwinism asks us to believe that evolution depends on random changes, when, by analogy with any other language, you should get gibberish – resulting in organisms being hopelessly ‘jammed’.

The argument is at least more sophisticated than the normal ‘how can random mutations create complexity’, in that he acknowledges that darwinism involves random mutations plus nonrandom selection for fitness.

But the flaw in Berlinski’s Language Jam argument is pretty obvious: it ignores the known facts. While random mutations which do render an organism so helpless that it dies are indeed common, so are all sorts of random DNA mutation which happen but simply do not ‘jam’ organisms. In fact, you need pretty sophisticated chemical science to find them at all.

As Orr puts it “The existence of subtle, functional, usable mutations in DNA is a simple fact that no amount of analogizing with computer programs can make go away. That random changes in computer programs -- but not DNA -- invariably jam things does not show that there is something wrong with Darwinism but that there is something wrong with the analogy.”

Actually, it’s worse than that for Berlinski. In another reply to the article, Karl F Wessel points out that numerous computer programs have in fact been run which replicate the processes of natural selection but do not ‘jam’:

The heart of David Berlinski's argument has been experimentally refuted, a result that is of more recent vintage than the obsolete mathematical metaphor he employs. In a 1986 experiment performed by Marshall Horwitz and Lawrence Loeb of the University of Washington, 19- base long messenger RNA promoter sequences were deleted from the genomes of E. coli bacteria and replaced by randomly synthesized sequences. Of the approximately 1011 possible sequences of the type, it turned out that many promoted the function of the deleted natural sequence (which confers resistance to tetracycline) as well as or better than the original. This was true even for a small subset of sequences randomly generated from two bases, i.e., from far fewer than 106 of the 1011. Nor did some of the most efficient sequences at all resemble the original.

Given this outcome and others like it, it is clear that something is radically wrong with Mr. Berlinski's analogy of biological genomes to computer programs. Either ge-nomes are nothing like programs, or else at least some programs are far more robust in the face of effects resembling natural selection than he imagines.

In point of fact, for several years people like John Koza of Stanford University have been using analogs of natural selection to evolve computer programs. Many of these evolved programs perform their optimizing tasks better than the best intentionally designed ones, providing the reductio ad absurdum of Mr. Berlinski's criticism.


So much for the Language Jam Argument.

The second argument against randomness producing complexity, which I’ll call the Monkey-Typewriter Target Argument, goes like this:

Berlinski starts with Dawkins’ famous analogy of the monkeys bashing at typewriters until they create an exact phrase from Shakespeare: “Methinks it is like a weasel”. The point of the analogy is to show that even though it would take billions of years for the monkeys to get this phrase if they were randomly hitting the keys, if you model it like evolution, saving each match and building upon it as in a recursive system, it doesn’t take that long for them to get it at all. So you have random mutation (the typing), plus natural selection (saving the matches to the original phrase each time, ie. once you’ve got the ‘M’ you save it and keep going til you’ve got an ‘e’, then save, then a ‘t’ and so on.)

Berlinski attacks this analogy by insisting that to have a ‘target’ of the phrase, you must have some kind of designer or monitor (a ‘Head Monkey’ ) who is overseeing the project, to make sure that all the time we’re getting nearer to our target of the phrase. Otherwise how will the monkeys know which letters to save? So in other words, darwinism, far from discarding a Designer, needs one to define the target and show how close we are to it.

So that’s the Monkey-Typewriter Target Argument. Can you spot the flaw? What is the original monkey typewriter analogy intended to show? It shows that, by saving favorable random changes, evolution can gradually build complex structures. So you do not need to wait for each part of a structure (all the letters in a phrase; the wings, eyes, feathers, digestive system etc of a bird) to appear miraculously at once. Natural selection is recursive: the output of the last generation feeds into the input of the next. It builds upon itself.

But, as Orr puts it in his response to Berlinski, the original analogy: “completely flubs another part of Darwinism: evolution does not, of course, work toward any "target." So how, then, does evolution know where to go? The answer is the most radical and beautiful part of Darwinism: it does not. The only thing that "guides" evolution is sheer, cold demographics. If a worm with a patch of light-sensitive tissue leaves a few more kids than a worm that cannot tell if the lights are on, that is where evolution will go. And, later, if a worm with light-sensitive tissue and a rough lens escapes a few more predators, that is where evolution will go. Despite all the loose talk (much of it, admittedly, from evolutionary biologists), evolution knows nothing of "design" and "targets."

So Berlinski ignores the non-teleological element of darwinism – which is absolutely fundamental and basic – and misinterprets the monkey-typewriter story as if it was meant to be a perfect analogy of all evolution, and not just a way of showing how natural selection builds upon itself.

I don’t think Berlinski is completely stupid, so I have to assume he does it deliberately, which is pretty poor show.


Balancing the scales
Let’s conclude with Berlinski’s own conclusion:




NO DOUBT, the theory of evolution will continue to play the singular role in the life of our secular culture that it has always played. The theory is unique among scientific instruments in being cherished not for what it contains, but for what it lacks. There are in Darwin's scheme no biotic laws, no Bauplan as in German natural philosophy, no special creation, no elan vital, no divine guidance or transcendental forces.


On the contrary. In lacking a recourse to divine guidance and transcendental forces, and in trying to work out the physical mechanisms for how something works without relying on magic, myth or mumbo-jumbo, darwinism is exactly like every other scientific theory worthy of the name.

What's unique is that darwinism is the only theory that is vilified for lacking these things. Nobody has an Intelligent Design theory of plate tectonics or diamond formation. If darwinism was limited only to explaining the natural history of plant-life, for example, I doubt there would be any such thing as an 'ID' objection.

ID exists because some religionists (not all) feel that darwinism threatens their beliefs. ID, with its false veneer of 'scientific enquiry' and its dressing of technical language, exists because Creationism has become an impossible position to hold and be taken remotely seriously. But ID is not a theory with any evidence from the natural world. There is only one source of positive evidence for it, which it shares with Creationism: the Old Testament.

To paraphrase a famous comment Salman Rushdie once made:

On one side of the scales is the Theory of Evolution: a massive body of incomplete, imperfect, but nonetheless considerable and ever-growing knowledge, painstakingly acquired from in-depth study of the natural world and constantly reappraised and tested. On the other is the Book of Genesis.

Only in Cloud Cuckoo Land, Kansas and Berlinski's head do the scales balance.

9 Comments:

Blogger Brit said...

Peter:

The problem here stems from a quite simple mistake that Berlinski and you make:

You take Dawkins' Monkey-Typewriter analogy out of context, and read too much into it.

The analogy is only designed to show that in a recursive system of mutation and natural selection, each new generation is not entirely randomly generated from afresh. The last generation is the input of the next generation.

It is written to answer a naive objection to darwinism: 'how can random mutatuion lead to complex organisms that work when the chances are infinitely remote?', and show that though mutation is random, selection for fitness is actually nonrandom. Because of this, you can get complex structures relatively quickly.

This is not controversial in terms of this is how the system itself works: you can set up computer programs to demonstrate it (obviously it is controversial in terms of whether evolution is a system of this kind).

If you read the original book 'The Blind Watchmaker', the analogy is in its context and it is quite obvious that it is there to show just this one point, and is not meant to be a complete analogy for evolution.

You make another mistake:

In rel life, mutation is not 'constant changes' in each generation. Most organisms resemble their parents pretty closely. Mutations can be rare. Most mutations are neutral - they don't affect the phenotype one way or the other. Some are harmful. Very rarely a mutation might be beneficial, it will be consistent with survival long enough for the phenotype to reproduce, and over the succeeding generations it might become prevalent in the population.

The famous finches show this to be an observable fact. Even Orrin admits it: his gripe is not with this, but on the specific issue of speciation.

This process depends on fitness, nothing else, so doesn't necessarily mean greater complexity. Sometimes it does, but sometimes it means greater simplicity.

(Incidentally, the Berlinski article and those replies are nearly 10 years old - it's not a recent objection, and darwinism has survived Berlinski's 'attack').

February 26, 2005 8:33 AM  
Blogger Unknown said...

Peter,
I'll second Brit's comments and add a few examples where I believe evolution has reduced unnecessary complexity.

Snakes are descended from lizards that had four legs. Once the snakes's ancestors happened upon their unique form of locomotion, the legs became unnecessary and, over time, disappeared.

Likewise with tails for the apes, and ourselves.

Although it may not have involved any decrease in compexity, the evolution of dolphins and whales, from sea-dwelling fish to land-dwelling mammals, then back to sea-dwelling creatures certainly should put to paid the notion that there is any direction to evolution.

February 27, 2005 7:50 AM  
Blogger Hey Skipper said...

Brit:

First off, you are an unusually good writer, and including that cite to the letters in Commentary was a great addition.

While I am being somewhat OT here, I have noticed that virtually everyone frequenting BroJudd Industries [clearly this blog's sire] is an unusually good writer--Peter, I am looking at you--a skill that is not particularly widespread.

As anyone who has looked at the comments sections of many blogs will quickly realize.

Peter:

You wrote:

We never hear of any species shedding unnecessary complexities and evolving towards the simple. What species can you name that evolved from bi-ped to quadri-ped in order to ease up the birthing process? Or anything at all analogous?Actually, we do. Flightless birds on oceanic islands devoid of predators are one example. Another is the loss of eyes in cave dwelling fishBut that is a relatively minor point.

Brit's comment about the fundamental mistake Berlinski makes with regard to the Monkey-Typewrite analogy is exactly on point, however I would like to add one thing. Imposing some particular work of Shakespeare on "success" is a ridiculous, and unrealistic constraint, because it takes for granted that which isn't required.

In evolution, the only thing that counts is successful parents. So, to avoid using the analogy incorrectly, and thereby imposing unsupportable conclusions, the correct filter to typing Monkeys is not Shakespeare, but whether the resulting character string is meaningful, where meaning is any syntactically correct sequence within the chosen language's rules.

So the sequence "Monkey briar cliff din 2004 lawyer" is meaningful, but "Monkey biar cliff din 2004 lawyert" is not. Also, note that "Monkey briarcliff dan 2004 lawyer" is also meaningful.

This is not a nonsensical distinction--not only does life exist in a multitude of forms, but the blueprint may get changed anywhere, not just at the end. What's more, using Shakespeare as the criteria--rather than mere survival and reproduction--is to impose an end-state design that evolution does not require, then accuse evolution of requiring it because of the analogy.

Finally, his continual evocation of a Head Monkey is also disingenuous. The Head Monkey, that he insists is the source of design, is nothing more than the sieve of life and death, where life is defined solely by the passing on of genes to the next generation.

Berlinski is clearly very intelligent, and within mathematics, at least, extremely knowledgeable. My objections to the analogy as he uses it are basic grammar theory. That he fails to acknowledge the inappropriateness of his analogy I find disturbing.


Changing gears, in reading Berlinski's response I noted this sentence:

"... the elaboration of the human mind, an organ unlike anything else found in the animal kingdom..."

Oh, really. Completely unlike? Wholly without any parallel to, say, the Chimpanzee brain? It doesn't have any structures even remotely similar to reptiles? Its organization doesn't bear any resemblance to other mammals?

I suspect the answers do not support his assertion; given that he relies almost wholly on appeals to incredulity, this is not a minor point.

February 27, 2005 7:51 AM  
Blogger Hey Skipper said...

On a separate note.

Unfortunately, given my interest in this subject, and how various motivations manifest themselves in the arguments, I probably won't be posting much, if at all, for the next month.

I head to Minneapolis tonight for a month requalifying in the DC-9, and other than getting a chance to say Hi to Duck, will probably be incommunicado for the duration--despite being something of a techno-geek, I don't yet have a laptop.

February 27, 2005 7:56 AM  
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