Monday, April 10, 2006

irreducible absurdity

"If it would be demonstrated that any complex organ existed which could not possibly have formed by numerous, successive, slight modifications, my theory would absolutely break down." Charles Darwin, The Origin of Species
These words have always been taken as both challenge and solution to the problem of 'Darwinism' that creationists fear. Since Charlie is dead, he has undergone every sort of assassination upon his character in order to discredit his revolutionary theses: namely , the general concept of natural selection, that the diversity of life is the result of inherited changes which provide adaptive advantages; and the specialized concept of this evolution in humanity and apes sharing a common ancestor. Scientific evidence has only come to increase the certainty of these insights over the years, while chipping away at some of the hesitations and counter-arguments provided by Darwin himself, as he could not rely on any appeal to genomics or population statistics in his time. Those concerns would be backfilled by thousands of researchers over the next century and a half, most of which tends to be disregarded in the rush to label all of Darwin's arguments.

Notably ape-like in appearance, poor ol' Chuck makes an exemplary strawman, full of all sorts of doubts about the evolution of complex organs like the eye and the absence of transitional fossils. Look at Darwin;s character is the underhanded assertion behind most of their rhetoric: he was a flawed man whose arguments must be flawed in character. Even if it were true that morality makes good natural philosophy or for rigorous objective criticism of the world, bad people make excellent and brilliant insights all the time without recourse to divine inspiration(cf. Machiavelli) and good people can live their entire existence in blissful ignorance of the oft-unpleasant mechanics of things.

But there is a great market for balms of the mind, carefully tailored information to inoculate one against dangerous ideas and concepts. Memetics, some say, will prove to be as useful to understanding the progression of human culture as genetics and natural selection. I think that assessment is overly ambitious, but memetics seems to hold great potential for describing the postmodern sphere of intersubjective knowledge. To put it more plainly, intersubjective knowledge is things people as a group all 'know' but can't 'prove', like the existence of the soul. Memetics helps us to describe what happens when competing beliefs interact: how they can be replicated, absorbed and destroyed. Beyond the facile biological metaphor of "belief as virus", memetics shows us the objective effects of cognitive processes, how a 'normal' person can become slave to a cult's dogma or why little Sally is especially susceptible to this kind of ad. Thus the development of new creationist counter-arguments continues unabated by evidence or reality.

One of the most prominent has been the irreducible complexity of Michael Behe, This was later developed into total solipistic sophistry by William Dembski, who believes that he can prove design by an intelligent creator through statistical mechanics, but keeps the whole revelation so close to the vest that no one else knows what he's talking about. Thus these people take any counter as the point to complain about how their opponents 'don't understand my brilliant arguements at all' as they turn around and mischaracterize what the point of contention was. For instance, one of the irreducibly complex components were the humble flagellum, which was claimed to be impossibly intricate and thus incapable of being assembled from scratch, as it were. Another claim was that since we can see evidence of all of the forms which came between say, a fish and a terrestrial lizard, how can we discount divine intervention in these gaps in the fossil record.

Recently both of these arguments have been smashed into little pieces;
in Wikipedia :
Tiktaalik is a genus of extinct sarcopterygian (lobe-finned) fishes from the late Devonian period, with many tetrapod-like features.It lived approximately 375 million years ago. Paleontologists suggest that Tiktaalik was an intermediate form between fish such as Panderichthys, which lived about 385 million years ago and early tetrapods such as Acanthostega and Ichthyostega that lived about 20 million years later. Its mixture of fish and tetrapod characteristics led its discoverers to characterize Tiktaalik as a "fishapod". [2]

Tiktaalik is a transitional fossil on par with Archaeopteryx. Its mixture of both fish and tetrapod characteristics include:

* fish
o fish gills
o fish scales
* fishapod
o half-fish, half-tetrapod limb bones and joints, including a functional wrist joint
o half-fish, half-tetrapod ear region
* tetrapod
o tetrapod rib bones
o tetrapod mobile neck
o tetrapod lungs

The discovery was published in the April 6, 2006 issue of Nature [1] and quickly recognized as a classic example of a transitional form. Jennifer Clack, a Cambridge University expert on tetrapod evolution, said of Tiktaalik, "It's one of those things you can point to and say, 'I told you this would exist,' and there it is."
and the NYT:
New molecular biology techniques let scientists begin to reconstruct how the processes inside a cell evolved over millions of years.

Dr. Thornton's experiments focused on two hormone receptors. One is a component of stress response systems. The other, while similar in shape, takes part in different biological processes, including kidney function in higher animals.

Hormones and hormone receptors are protein molecules that act like pairs of keys and locks. Hormones fit into specific receptors, and that attachment sends a signal to turn on — or turn off — cell functions. The matching of hormones and receptors led to the question of how new hormone-and-receptor pairs evolved, as one without the other would appear to be useless.

The researchers found the modern equivalent of the stress hormone receptor in lampreys and hagfish, two surviving jawless primitive species. The team also found two modern equivalents of the receptor in skate, a fish related to sharks.

After looking at the genes that produced them, and comparing the genes' similarities and differences among the genes, the scientists concluded that all descended from a single common gene 450 million years ago, before animals emerged from oceans onto land, before the evolution of bones.

The team recreated the ancestral receptor in the laboratory and found that it could bind to the kidney regulating hormone, aldosterone and the stress hormone, cortisol.

Thus, it turned out that the receptor for aldosterone existed before aldosterone. Aldosterone is found just in land animals, which appeared tens of millions of years later.

"It had a different function and was exploited to take part in a new complex system when the hormone came on the scene," Dr. Thornton said.

What happened was that a glitch produced two copies of the receptor gene in the animal's DNA, a not-uncommon occurrence in evolution. Then, for reasons not understood, two major mutations made one receptor sensitive just to cortisol, leading to the modern version of the stress hormone receptor. The other receptor became specialized for kidney regulation.

Dr. Thornton said the experiments showed how evolution could and did innovate functions over time. "I think this is likely to be a very common theme in how complex molecular systems evolved," he said.
Of course, this had no effect for the creationists, who argue that this is not significant enough for their rigorous standards. Few people live long enough to see their beliefs so throughly discredited.

Español | Deutsche | Français | Italiano | Português| Ch| Jp| Ko

0 Comments:

:
:
:

BloggerHacks

Links to this post:

Create a Link

<< Home


All original material of whatever nature
created by Nicholas Winslow and included in
this weblog and any related pages, including archives,
is licensed under a Creative Commons
Attribution-Noncommercial-Sharealike license
unless otherwise expressly stated (2006)