And So, Back to Finches
The forms of adult animal bone-muscle systems are influenced to a large degree by the forces that act on them while they are growing. Jaws and teeth have to bear the forces exerted when the animal chews its food, and these forces will depend in strength and direction on the kind of food the animal eats. The adult form of jaws and teeth that develops in many rodents, for example, can vary over wide ranges with changes in diet, brought about possibly by environmental factors or through a new habit spreading culturally through a population. If the new conditions or behavior become established, the result can be a permanent change in the expressed phenotype of the animal.
In 1967, a hundred or so finches of the same species were brought from Laysan, an island in the Pacific about a thousand miles northwest of Hawaii, forming part of a U.S. government bird reservation, to a small atoll called Southeast Island, somewhat southeast of Midway, which belongs to a group of four small islands all within about ten miles of each other. Twenty years later, the birds had dispersed across all the islands and were found to have given rise to populations having distinct differences, particularly with regard to the shapes and sizes of their beaks. 33 Clearly this wasn't the result of randomly occurring mutations being naturally selected over many generations. The capacity to switch from one form to another was already present in the genetic program, and the program was switched to the appropriate mode by environmental signals. The ironic aspect of this example, of course, is that observations of precisely this type of variety in beak forms among finches of the Galapagos Islands led Darwin to the notion that he was witnessing the beginnings of new species.
Confronting the Unthinkable
By the above, if a population of rodents, say, or maybe horses, were to shift their diet abruptly, the phenotype would change abruptly even though the genotype does not. The fossil record would show abrupt changes in tooth and bone structure, even though there had been no mutation and no selection. Yet the evolution read into the fossil record is inferred largely from bones and teeth. In his reconstruction of the story of horse evolution, Simpson tells that when the great forests gave way to grassy plains, Mesohippus evolved into Merychippus, developing high-crowned teeth through random mutation and selection, for "It is not likely to be a coincidence that at the same time grass became common, as judged by fossil grass seeds in the rocks." 34
It may indeed have been no coincidence. But neither does it have to be a result of the mechanism that Simpson assumes. If these kinds of changes in fossils were cued by altered environments acting on the developing organisms, then what has been identified as clear examples of evolution could have come about without genetic modification being involved, and with random mutation and selection playing no role at all.
Should this really be so strange? After all, at various levels above the genetic, from temperature regulation and damage repair to fighting or fleeing, organisms exhibit an array of mechanisms for sensing their environment and adjusting their response to it. The suggestion here is that the principle of sensing and control extends down also to the genetic level, where genes can be turned on and off to activate already-existing program modules, enabling an organism to live efficiently through short-term changes in its environment. Nothing in the genome changes. The program is set up for the right adaptive changes in the phenotype to occur when they are needed.
The problem for Darwinism, and maybe the reason why suggestions of directed evolution are so fiercely resisted, is that if there was trouble enough explaining the complexity of genetic programs before, this makes it immeasurably worse. For now we're implying a genome that consists not only of all the directions for constructing and operating the self-assembling horse, but also all the variations that can be called up according to circumstances, along with all the reference information to interpret the environmental cues and alter the production specification accordingly. Fred Hoyle once observed that the chances of life having arisen spontaneously on Earth were about on a par with those of a whirlwind blowing through a junkyard containing all the pieces of a 747 lying scattered in disarray, and producing an assembled aircraft ready to fly. What we're talking about now is a junkyard containing parts for the complete range of Boeing civil airliners, and a whirlwind selecting and building just the model that's best suited to the current situation of cost-performance economics and projected travel demands.
Intelligence at Work? The Crux of It All
So finally we arrive at the reason why the subject is not just a scientific issue but has become such a battle of political, moral, and philosophic passions. At the root of it all, only two possibilities exist: Either there is some kind of intelligence at work behind what's going on, or there is not. This has nothing to do with the world's being six thousand years old or six billion. A comparatively young world—in the sense of the surface we observe today—is compatible with unguided Catastrophist theories of planetary history, while many who are of a religious persuasion accept orthodox evolution as God's way of working. What's at the heart of it is naturalism and materialism versus belief in a creative intelligence of some kind. Either these programs which defy human comprehension in their effectiveness and complexity wrote themselves accidentally out of mindless matter acting randomly; or something wrote them for a reason. There is no third alternative.
Darwin's Black Box Opened:
Biochemistry's Irreducible Complexity
At the time Darwin formulated his original theory, nothing was known of the mechanism of heredity or the internal structures of the organic cell. The cell was known to possess a dark nucleus, but the inner workings were pretty much a "black box," imagined to be a simple unit of living matter, and with most of the interesting things taking place at higher levels of organization. With the further development of sciences leading to the molecular biology that we see today, this picture has been dramatically shattered and the cell revealed as the stupendous automated factory of molecular machines that we glimpsed in Michael Denton's description earlier. The complexity that has been revealed in the last twenty years or so of molecular biochemistry is of an order that dwarfs anything even remotely imagined before then.
These findings prompted Michael Behe, professor of biochemistry at Lehigh University in Pennsylvania, to write what has become an immensely popular and controversial book, Darwin's Black Box, 35 in which he describes systems ranging from the rotary bearings of the cilia that propel mobile cells, to vision, the energy metabolism, and the immune system, which he argues cannot have come into existence by any process of evolution from something simpler. His basis for this assertion is the property they all share, of exhibiting what he terms "irreducible complexity." The defining feature is that every one of the components forming such a system is essential for its operation. Take any of them away, and the system is not merely degraded in some way but totally incapable of functioning in any way at all. Hence, Behe maintains, such systems cannot have arisen from anything simpler, because nothing simpler—whatever was supposed to have existed before the final component was added—could have done anything; and if it didn't do anything, it couldn't have been selected for any kind of improvement. You either have to have the whole thing—which no variation of evolution or any other natural process could bring into existence in one step—or nothing.
The example he offers to illustrate the principle is the common mousetrap. It consists of five components: a catch plate on which the bait is mounted; a holding bar that sets and restrains the hammer; a spring to provide the hammer with lethal force; and a platform for mounting them all on and keeping them in place. Every piece is essential. Without any one, nothing can work. Hence, it has to be built as a complete, functioning unit. It couldn't assume its final form by the addition of any component to a simpler model that was less efficient.
An example of reduced complexity would be a large house built up by additions and extensions from an initial one-room shack. The improvements could be removed in reverse order without loss of the essential
function it provides, though the rendering of that function would be reduced in quality and degree.
Here, from Behe's book, are the opening lines of a section that sketches the process of vision at the biochemical level. Nobody has been able to offer even a speculation as to how the system could function at all if even one of its molecular cogs were removed.
When light first strikes the retina a photon interacts with a molecule called 11-cis-retinal, which rearranges within picoseconds [a picosecond is about the time light takes to cross the width of a human hair] to trans-retinal. The change in the shape of the retinal molecule forces a change in the shape of the protein rhodopsin, to which the retinal is tightly bound. The protein's metamorphosis alters its behavior. Now called metarhodopsin II, the protein sticks to another protein, called transducin. Before bumping into metarhodopsin II, transducin had tightly bound a small molecule called GDP. But when transducin interacts with metarhodopsin II, the GDP falls off, and a molecule called GTP binds to transducin.
Concluding, after three long, intervening paragraphs of similar intricacy:
Trans-retinal eventually falls off rhodopsin and must be reconverted to 11-cis-retinal and again bound by rhodopsin to get back to the starting point for another visual cycle. To accomplish this, trans-retinal is first chemically modified by an enzyme called trans-retinol—a form containing two more hydrogen atoms. A second enzyme then converts the molecule to 11-cis-retinol. Finally, a third enzyme removes the previously added hydrogen atoms to form 11-cis-retinal, a cycle is complete. 36
The retinal site is now ready to receive its next photon.
Behe gives similarly comprehensive accounts of such mechanisms as blood clotting and the intracellular transport system, where the functions of all the components and their interaction with the whole are known in detail, and contends that only purposeful ordering can explain them. In comparison, vague, less precisely definable factors such as anatomical similarities, growth of embryos, bird lineages, or the forms of horses become obsolete and irrelevant, more suited to discussion in Victorian drawing rooms.
The response from the evolutionists to these kinds of revelations has been almost complete silence. In a survey of thirty textbooks of biochemistry that Behe conducted, out of a total of 145,000 index entries, just 138 referred to evolution. Thirteen of the textbooks made no mention of the subject at all. As Behe notes, "No one at Harvard University, no one at the National Institutes of Health, no member of the National Academy of Sciences, no Nobel prize winner—no one at all can give a detailed account of how the cilium, or vision, or blood clotting, or any other complex biochemical process might have developed in a Darwinian fashion." 37
Behe unhesitatingly sees design as the straightforward conclusion that follows from the evidence itself—not from sacred books or sectarian beliefs. He likens those who refuse to see it to detectives crawling around a body lying crushed flat and examining the floor with magnifying glasses for clues, while all the time ignoring the elephant standing next to the body—because they have been told to "get their man." In the same way, Behe contends, mainstream science remains doggedly blind to the obvious because it has fixated on finding only naturalistic answers. The simplest and most obvious reason why living systems should show over and over again all the signs of having been designed—is that they were.
Acknowledging the Alternative: Intelligent Design
Others whom we have mentioned, such as Denton, Hoyle, Spetner, express similar sentiments—not through any prior convictions but purely from considerations of the scientific evidence. Interest in intelligent design has been spreading in recent years to include not just scientists but also mathematicians, information theoreticians, philosophers, and others dissatisfied with the Darwinian theory or opposed to the materialism that it implies. Not surprisingly, it attracts those with religious interpretations too, including fundamentalists who insist on a literal acceptance of Genesis. But it would be a mistake to characterize the whole movement by one constituent group with extreme views in a direction that isn't really relevant, as many of its opponents try to do—in the same way that it would be to belittle the notion of extraterrestrial intelligence because UFO abduction believers happen to subscribe to it. As Phillip Johnson says, "ID is a big tent" that accommodates many diverse acts. All that's asserted is that the evidence indicates a creative intelligence of some kind. In itself, the evidence says nothing about the nature of such an intelligence nor what its purpose, competence, state of mind, or inclination to achieve what we think it should, might be.
The argument is sometimes put forward that examples of the apparent lack of perfection in some aspects of biological function and adaptation mean that they couldn't be the work of a supreme, all-wise, all-knowing creator. This has always struck me as curious grounds for scientists to argue on, since notions of all-perfect creators were inventions of opponents more interested in devising means for achieving social control and obedience to ruling authorities than interpreting scientific evidence. Wrathful gods who pass judgments on human actions and mete out rewards or retribution make ideal moral traffic policemen, and it seems to be only a matter of time (I put it at around 200–300 years) before religions founded perhaps on genuine insights for all I know are taken over by opportunists and sell out to, or are coopted by, the political power structure. In short, arguments are made for the reality of some kind of creative intelligence; human social institutions find that fostering belief in a supreme moral judge is to their advantage. Nothing says that the two have to be one and the same. If the former is real, there's no reason why it needs to possess attributes of perfection and infallibility that are claimed for the latter. Computers and jet planes are products of intelligence, but nobody imagines them to be perfect.
Those who are persuaded by religious interpretations insist on the need for a perfect God to hand down the absolute moral standards which they see as the purpose in creating the world—and then go into all kinds of intellectual convolutions trying to explain why the world clearly isn't perfect. I simply think that if such an intelligence exists it would do things for its reasons not ours, and I don't pretend to know what they might be—although I could offer some possibilities. An analogy that I sometimes use is to imagine the characters in a role-playing game getting complex enough to become aware that they were in an environment they hadn't created, and which they figure couldn't have created itself. Their attempts to explain the reason for it all could only be framed in terms of the world that they know, that involves things like finding treasures and killing monsters. They could have no concept of a software writer creating the game to meet a specification and hold down a job in a company that has a budget to meet, and so on.
I sometimes hear the remark that living things don't look like the products of design. True enough, they don't look very much like the things we're accustomed to producing. But it seems to me that anyone capable of getting self-assembling protein systems to do the work would find better things to do than spend their existence bolting things together in factories. Considering the chaotically multiplying possibilities confronting the development of modules of genetic code turned loose across a range of wildly varying environments to make what they can of themselves, what astounds me is that they manage as well as they do.
These are all valid enough questions to ask, and we could spend the rest of the book speculating about them. But they belong in such realms of inquiry as theology and philosophy, not science.
Is Design Detectable?
How confident can we be that design is in fact the necessary explanation, as opposed to some perhaps unknown natural process—purely from the evidence? In other words, how do you detect design? When it comes to nonliving objects or arrangements of things, we distinguish without hesitation between the results of design and of natural processes: a hexagonal, threaded nut found among pebbles on a beach; the Mount Rushmore monument as opposed to a naturally weathered and eroded rock formation; a sand castle on a beach, distinguished from m
ounds heaped by the tide. Exactly what is it that we are able to latch on to? If we can identify what we do, could we apply it to judging biological systems? William Dembski, who holds doctorates in mathematics and philosophy from the Universities of Chicago and Illinois, has tackled the task of setting out formally the criterion by which design is detected. 38 His analysis boils down to meeting three basic conditions.
The first is what Dembski terms "contingency": that the system being considered must be compatible with the physics of the situation but not required by it. This excludes results that follow automatically and couldn't be any other way. Socrates, for example, believed that the cycles of light and darkness, or the progressions of the seasons pointed toward design. But what else could follow day except night? What could come after cold but warming, or after drought other than rain?
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