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Intellectuals Who Find Darwinism Unconvincing
By William A. Dembski
ISI BooksCopyright © 2004 ISI Books
All rights reserved.
Robert C. Koons
The Check Is in the Mail
Why Darwinism Fails to Inspire Confidence
Darwinism owes its present dominance to the widespread misperception that it has refuted the design argument. In particular, it is thought to have refuted the ancient argument from the complexity of biological functions to the existence of an intelligent creator. Yet except for specifying a few minor adjustments in pre-existing functions (like those required for resistance to antibiotics), evolutionary biologists have failed to offer any detailed scenarios demonstrating that the Darwinian mechanism of accidental variations and natural selection is an adequate substitute for intelligent creation. The mere logical possibility that such scenarios might someday be found is not sufficient evidence to raise genuine doubts about the reality of creation, much less to provide solid grounds for denying it.
Methodological naturalism, the rule that the natural sciences must proceed without invoking intelligent causes, would be justified if Darwinists first provided adequate, independent grounds for believing that natural, unintelligent causes produced many of the sophisticated biological functions we observe. But no such grounds have been provided. Instead, the assertion of methodological naturalism has been used to substitute theft for honest labor, insulating Darwinian theories from all possible criticism. Darwinism has been part of a metaphysical attack on the very idea of agency, both human and superhuman, that has been ongoing for two hundred years. By undermining the idea of reasonable and responsible agency, Darwinism has facilitated a variety of experiments in social engineering.
Two Metaphysical Models
The evidence for evolution, at least the evidence available to a layperson like myself, is far from compelling. It seems compelling only to those with a prior commitment to metaphysical materialism, for whom Darwinism is practically the only reasonable explanation available for life as we know it. As is well known, the fossil record of the family tree of evolution is so gappy that it consists of a great deal more gap than tree. This is especially true where the record is most complete, as in the case of the invertebrates. The missing links that have been found, like the Archaeopteryx or Australopithecus, are better described as mosaics: recombinations of adaptations found in what are assumed to be related families. Given that the forms of life found in the fossil record are more numerous and variegated than those we find alive today, it is not at all surprising that we should find fossil forms that are "intermediate" in some vague sense between living forms. What we don't find is the kind of continuous, seamless web of transformation of adaptive structures that would be needed to confirm the truth of Darwinism.
Of course, if evolution is defined broadly enough, there's little doubt that it has occurred. We do find a gradual "unfolding" of life (the original meaning of "evolution"): invertebrates appear before vertebrates, coniferous before flowering plants, small primates before great apes, and so on. This fact was well known before Darwin's work appeared. Darwin's crucial contention was that he had found the underlying causal mechanism driving this unfolding: the culling of variation by the competition for survival. Since Mendel's work was not yet known, variation was considered to appear by means of some mysterious process, but it was a process that was hypothesized to be blind, purposeless, and subhuman. When the Darwinian idea was combined with Mendelian genetics, resulting in the neo-Darwinian synthesis, the defining differential element of the theory was this: the probability of the occurrence of any mutation is unrelated to its prospective contribution to the functionality of any structure, present or future. Contributions to function affect only the chances of the mutation's successful propagation, not its original appearance.
Such a theory was, of course, a direct challenge to a widely held alternative account: one that attributed the origin of complex adaptations in living things to some form of irreducible intelligent agency, whether of a divine providence outside nature or a pervasive purposiveness within it. This alternative had reached its fullest state of development in the late eighteenth and early nineteenth centuries in France and England, especially. But this French and British natural theology was the culmination of a continuous tradition stretching back to the Greek philosophers, especially Plato, Aristotle, and the Stoics; and to the wisdom literature of the Hebrews, especially the Psalms, Job, the Wisdom of Solomon, and Ecclesiastes. It is true that, prior to William Paley's Natural Theology in 1803, which investigated the internal mechanics of biological organisms, traditional natural theology did not focus exclusively on that internal, watch-like order. The orderly operations of the heavens and the generosity of the earth's environment for the continuation of life were most often cited as proof of a divine artificer. However, it is by no means the case that the mutual adjustment of bodily organs was overlooked.
The author of Job directs our attention to the biological world: "But now ask the beasts, and they will tell you; and the birds of the air, and they will tell you; or speak to the earth, and it will teach you; and the fish of the sea will explain it to you. Who among all these does not know that the hand of the Lord has done this?" (Job 12:7–9). Of course, Job is not recommending literal conversations with the animals. Instead, his point is that a careful study of the forms of animal life leads inescapably to the conclusion that they are the creatures of God. In Ecclesiasticus, the functionality and interdependency of natural forms is taken as proof of God's wisdom in crafting the world: "He hath garnished the excellent works of his wisdom. O how desirable are all his works.... All things are double against another, and he hath made nothing imperfect. One thing establisheth the good of another; and who shall be filled with beholding his glory?" (Ecclesiasticus 42:21–25).
Among the Greeks, the tendency was to find a kind of intelligence or wisdom immanent within the world, rather than embodied in a transcendent creator. Greeks and Hebrews were, however, at one in insisting that the world could be understood only in terms of the unfolding of an intelligent purpose. Pre-Socratic philosophers, like Anaximenes, Anaxagoras, Heraclitus and Xenophanes, thought that the order of the world required a mind (nous) or rational principle (logos) acting in a fundamental and pervasive agency. Plato's Socrates, in the Phaedo, gives voice to the conviction that science must give pride of place to the category of purposeful action. Socrates reports that his youthful enthusiasm for physicalistic explanations of natural phenomena disappeared when he encountered Anaxagoras's hypothesis that Mind directs and causes all things. This opened up a new way of explaining biological and other natural phenomena: "to find the cause of each thing ... one had to find the best way for it to be" (Phaedo 97d).
Aristotle rejected the materialistic theory of evolution that was proposed by Empedocles and the atomists. He argued that we can make sense of biology only by taking purposiveness, final causation, to be an irreducible and primary reality. He repeatedly insisted that "nature does nothing in vain" (De Caelo 271a33, Parts of Animals 658a9, Generation of Animals 741b13) and that "nature invariably brings about the best arrangement of those that are possible" (PA 658a24). It is true that "nature" probably does not name (for Aristotle) a nature-transcending designer, but it does stand for an efficacious and fundamentally purposeful principle of explanation.
In both the Laws (Book X) and the Timaeus, Plato appealed to the order of the world as evidence for an intelligent creator, and this form of argument was sustained by the Stoics and by Cicero, bringing the Greek tradition even closer to the Hebrew. The synthesis of the Hebrew and Greek traditions appeared in the first century A.D. in the works of Hellenistic Jews like Philo, Josephus, and the apostle Paul. Augustine of Hippo in the fourth century argued that biological form had to be explained in terms of "rational seeds" implanted in matter at the very first moment of creation. For Augustine, the subsequent evolution of life through the remaining "six days" of creation, which he pointedly refrained from interpreting as a literal period of 144 hours, was a literal unfolding of a multitude of pre-established divine designs.
Both Aristotle and Augustine illustrate the fact that challenges to Darwinism do not require the postulation of gaps or discontinuities in nature, or of ongoing interventions or intrusions from the supernatural. The crucial question is this: when novel forms of adaptation first appear, and before natural selection has had a chance to operate, is the probability of their emergence dependent on or independent of their functionality? Natural selection can explain only why functional forms persist and operate, not how they came to be there in the first place. For Plato, Aristotle, Augustine, and the other teleologists, the origin of biological function requires an irreducibly purposeful principle, or intelligent design.
The anti-teleological view that attempts to explain or explain away the appearance of design and purpose in nature did not originate with Darwin. Precursors of Darwin's theory of materialistic evolution through natural selection can be found in antiquity in Empedocles and Lucretius, and in the eighteenth century in David Hume. Naturalistic evolution is an approach that predates the birth of science and may well outlast it.
The Burden of Proof
The Western philosophical tradition has thus bequeathed to us two competing metaphysical models: one in which everything is to be explained ultimately in terms of blind and purposeless forces (the materialistic model); and one in which purposefulness is a fundamental and irreducible reality (the teleological model). The most important question, from an epistemological point of view, is this: where should we locate the presumption of truth, and where the burden of proof? There are compelling grounds for placing the burden of proof on the materialistic model. Even stalwart Darwinists like Richard Dawkins admit that the defining task of biology is to explain the existence of things that appear to be designed. Cicero, in On the Nature of the Gods, Book II, reports Aristotle's cave analogy: if a group of people had spent all of their lives underground and then emerged on the surface, they would be bound to think of the biologically rich world they discovered there to be the product of intelligence. Only familiarity dulls our sense of wonder at the craftsmanship of nature.
In his Essays on the Intellectual Powers of Man, eighteenth-century Scottish philosopher Thomas Reid cites the capacity to recognize the signs of intelligent agency as part of the basic equipment of the human mind. Without such a basic capacity, the means by which we recognize one another as intelligent and purposeful would remain mysterious. How we recognize intelligence even in our own behavior would be a mystery as well. When this basic faculty of intelligence-recognition considers the machinery of living things, the clear answer it delivers is yes, there is intelligence and purposefulness displayed in such machinery. If this was true 2500 years ago, in the time of Aristotle, how much more true is it now that we know so much about the astonishingly superb design of the biomolecular machinery of the cell?
Nonetheless, the natural deliverances of our sense of intelligence can be defeated since, as in all other matters, our faculties are fallible on this question. It is therefore possible in principle for materialists to overcome the presumption of intelligence by means of a rationally compelling case. Still, there is an undeniable burden of proof that must first be assumed.
In The Origin of Species, Darwin recognized this fact. The argumentative structure of the book concedes that the presumption of reason lies with intelligent creation. Moreover, Darwin recognized that he could not yet shift the burden of proof. He was concerned, quite justifiably, with providing enough provisional evidence to create an atmosphere of open-mindedness. He hoped to convince biologists that his theory shouldn't be dismissed out of hand but should instead be given a fair chance by being given the chance to be fleshed out with specific hypotheses that could then be tested against the relevant evidence. At this task, I believe he was entirely successful. No reasonable person could, after reading the Origin, deny that this was a theory worthy of being taken seriously. At the least it justified an investigation into whether the evolutionary mechanism proposed was really adequate to its appointed task, and whether sufficient circumstantial evidence could be found substantiating that the mechanism of natural selection had in fact been at work.
To meet the burden of proof, there were two gaps that had to be filled: (1) Darwin's sketchy schema of variation and selection had to be filled out, in particular cases, with sufficient detail to verify that variation and natural selection could in fact be responsible for adaptations that had the appearance of being the product of intelligent design; and (2) particular hypotheses produced in this way had to be tested against the available evidence, both in the fossil record and in vestigial homologies, those remnants of organisms whose similarities indicated a common origin. Note that the second task presupposes success at the first: to attempt to test a vague, schematic model of "variation with selection" or "random mutations and selection" rather than specific scenarios is to attempt the impossible. Any evidence that is found can be made to accord with schematic Darwinism, and so can be counted as evidence "for" the theory. Only by replacing the schema with a specific sequence of possible mutations and selective pressures can we find something that is both falsifiable and confirmable by collateral evidence. But this is exactly what has never happened, no doubt because of the problems of intractability, the inability to manage or control the reconstruction of the genotypes of extinct and even unattested hypothetical ancestors. Whatever the reason, the burden of proof was never met, and the presumption of design never rebutted.
Take, for example, Richard Dawkins's attempts to prove that Darwinism is able to explain the emergence of the vertebrate eye. Dawkins refers to a computer simulation by Nilsson and Pelger, showing that one can gradually improve a light sensitive spot and reach, in 1800 steps or so, a fully functional, lens-bearing eye. This might be impressive, except that the computer simulation (like every single simulation referred to by Dawkins in the book) entirely omits the two crucial details about real biology: the genotype/phenotype distinction (the distinction between the genetic constitution of an individual or group as opposed to the properties produced by interaction with its environment) and the processes of embryological development. The steps in Nilsson and Pelger's program are phenotypical (that is, they concern changes in gross, morphological features in the fully formed adult). We are not given a model in which the successive forms of the eye are determined by successive trajectories of embryological development, nor are we given a model of how these successive trajectories are determined by successive, feasible mutations. Given these limitations, it is of course impossible to estimate the probabilities of the mutations required for each of the 1800 steps in the creation of the vertebrate eye. The model cannot be used to generate even a single prediction about present-day residues of the actual history of the eye. In other words, Dawkins's favorite model, the best now available, has not made even the smallest significant step beyond the bare speculations of Empedocles, Hume or Darwin.
Excerpted from Uncommon Dissent by William A. Dembski. Copyright © 2004 ISI Books. Excerpted by permission of ISI Books.
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