The Core of Dembski's Case for ID
In his latest book, No Free Lunch, William A. Dembski argues at length (as he has done in several other works) that there are natural objects in the world that a) we can unambiguously identify as objects that could not be the outcome of unguided natural processes alone, and b) must therefore be the products of intelligent design.[1]
How would we recognize these remarkable objects? They exhibit, says Dembski, the empirically detectable quality he calls specified complexity. And why is it that these objects must be the products of intelligent design? Because, according to Dembski, unguided natural processes are inherently incapable of generating specified complexity. That is something that only intelligence is able to do.
In the cultural context of the creation-evolution debate, the natural objects of greatest interest here are biological systems. Dembski's favored example is the bacterial flagellum, a quite remarkable molecular machine that functions as a propeller for some bacteria, such as E. coli. This rotary propulsion system also played a prominent role in Michael Behe's book, Darwin's Black Box, as an example of a biotic system that exhibits the quality he called irreducible complexity. Dembski considers irreducible complexity-after he carefully redefines and qualifies the meaning of Behe's term-to be a special form of his more broadly defined specified complexity.
Now, if there are biological systems that-because they exhibit specified complexity-could not have been actualized by natural processes alone, then, argues Dembski, some unembodied intelligent agent must have done something to bring about this naturally impossible outcome. A non-natural action called intelligent design must have made possible what nature, unguided by any interactive intelligence, was wholly incapable of doing. That is Dembski's core claim-the claim on which the intelligent design movement either stands or falls. Hence the subtitle of his book: Why Specified Complexity Cannot Be Purchased Without Intelligence.
Why focus on the bacterial flagellum?
The natural sciences concern themselves with a vast diversity of physical, chemical and biological processes that transform some system of interest from an initial state (i) to a final state (f). Evolutionary biology, for example, deals at length with the processes by which organisms, employing their own functional and transformational capabilities and interacting with both their physical and ecological environments, change in the course of time. Substantial progress has been made in the scientific effort to become acquainted with the numerous processes relevant to evolutionary transformations, but even more remains to be discovered and comprehended.
The vast majority of Dembski's argumentation in No Free Lunch focuses the reader's attention on his particular concept of the way in which these transformational processes might be limited and constrained by the logical and mathematical requirements of information theory. In Dembski's judgment, the scientific community has been lax in its dealing with these limitations and constraints, especially as they apply to the Darwinian mechanism for evolution. By presuming that all of the transformations of interest to evolutionary biology can be accomplished by purely natural processes, the scientific community has failed, in Dembski's judgment, to give due consideration to the limitations of natural causation and the consequent necessity for supplemental action by a non-natural intelligent agent.
Sometimes, however, Dembski's purely theoretical argumentation regarding these issues seems abstruse and esoteric, far removed from the real life things to which scientific theories are supposed to apply. Concrete illustrations then become essential. In my experience, the key to understanding the character or quality of Dembski's abstract theories is to see how he applies them to specific biological systems. That's where the case of the bacterial flagellum comes into play.
In Dembski's judgment, a straightforward application of his "design-theoretic reasoning" will clearly demonstrate the need for designer action. "Design-theoretic explanations are concerned with determining whether some particular event, object, or structure exhibits clear marks of intelligence and can thus be legitimately ascribed to design."[2] Focusing on the arena of biotic evolution, Dembski believes that he is now in a position to demonstrate convincingly that "transforming a biological system that does not exhibit an instance of specified complexity (say a bacterium without a flagellum) into one that does (say a bacterium with a flagellum) cannot be accomplished by purely natural means but also requires intelligence."[3] This is the specific claim that we wish to examine.[4]
Getting Acquainted With the ID Vocabulary
Before we proceed with our analysis of Dembski's case for the intelligent design of the bacterial flagellum, we need to invest a substantial effort to become familiar with the fundamental goals and vocabulary of the ID movement. Knowing the broad goals of the movement will help us to understand some elements of its rhetorical strategy. Knowing the vocabulary of the movement is essential because of the strategic manner in which familiar words are often assigned specialized or unusual meanings in ID literature.
The many faces of naturalism
In large part, the ID movement is a reaction to its leaders' perception that the worldview of naturalism has effectively dominated the worlds of higher education and professional science, and that it is now providing the religious framework for the K-12 public educational system as well. The ID movement is committed to the defeat of naturalism. But naturalism comes in many different versions that must, I believe, be carefully distinguished from one another. I find the following distinctions to be essential.
(1) I use the term maximal naturalism (or ontological naturalism) to denote the comprehensive worldview built on the premise that Nature is all there is-there is no other form of being, no God or gods-and that there is no ultimate purpose in its existence, character, or historical development.[5] This point of view could also be identified by such labels as materialism (the material/physical world is all there is) or atheism (there is no transcendent God as envisioned by any of the theistic religions).
(2) I use the term minimal naturalism (it could also be called metaphysical naturalism, but that name has additional connotations) to denote the family of worldviews that reject the idea of supernatural action by any deity. All actions (processes and events) in the universe are presumed to fall entirely in the category of natural actions-actions performed by members of the natural world in ways that are wholly consistent with their own character and capabilities. Although the existence of God, or gods, or purpose is neither affirmed nor denied by minimal naturalism, the idea that any divine being would act supernaturally-that is, coercively overpowering or superceding the natural actions of members of the universe, thereby interrupting the flow of natural phenomena-is rejected. (Intelligent Design advocate Phillip Johnson frequently uses the term scientific naturalism, which appears to be minimal naturalism, as here defined, substantially modified by adding the assertions that natural actions are purposeless and that science provides the only reliable pathway to knowledge. Given these additions, Johnson's label, scientific naturalism, comes very close to what we are calling maximal naturalism.)
(3) The term methodological naturalism is often employed to denote the idea that the natural sciences have the competence to investigate natural actions alone and must remain agnostic with regard to any form of divine action.
(4) Naturalistic theism builds its worldview on the premise that there is a God who acts purposefully and effectively in the world, but this divine action is always persuasive and never coercive. In contrast to the several forms of supernaturalistic theism, naturalistic theism rejects coercive supernatural intervention as something that would violate the essential natures of God, the world, and the God-world relationship.
The ID movement, we noted, is committed to the defeat of "naturalism." But toward which form of naturalism does it aim its rhetorical guns? There may be some variation in the ID literature, but the consensus seems to be that it doesn't really matter very much. In the judgment of most ID proponents, the distinctions outlined above are effectively meaningless because all of these versions of naturalism agree on the key proposition to which the ID movement takes exception-that there is no way to detect divine action empirically. The distinctions noted above are judged by ID spokespersons to be hollow rhetorical distinctions without an empirically discernable difference.
Among the chief claims of the ID movement is that design is empirically detectable. In Dembski's words, "Design is detectable; we do in fact detect it; we have reliable methods for detecting it....As I have argued throughout this book, design is common, rational, and objectifiable."[6] That being the claim, then each and every one of the forms of naturalism listed above-because they uniformly reject the empirical detectability of divine action-is the target for defeat. To the ID movement, to be a God who is not empirically detectable is to a dispensable God. Any God whose actions are not empirically detectable would be of no value in defeating naturalism. Naturalism would always be able to say, in effect, "A God who can never do anything that makes a difference, and of whom we can have no reliable knowledge, is of no importance to us."[7] The God envisioned by the chief proponents of ID, on the other hand, is a God who makes an empirically detectable difference.
Doing what comes naturally
The ID movement has labored vigorously to formulate a way to determine how things came to be actualized (assembled, arranged, organized, constructed) in the course of time. In contrast to theology's concern-in its doctrine of creation-for how any universe came to have its being (its existence and/or its particular character) in the first place, the ID movement is concerned with portions of the universe's formational history. In Dembski's words, "Design is fundamentally concerned with arrangements of pre-existing stuff that signify intelligence."[8] When looking at some natural object (any object not crafted by human or animal action, usually some organism or part of an organism), the question for ID advocates is, Could this object have been actualized by means of natural processes (or natural causes) alone?
Purely natural processes are those that can be fully accounted for by the actions and interactions of the materials (or "stuff") of which the object and its environment are composed. These are the processes that the natural sciences are equipped to describe in terms of the empirically known mechanisms by which atoms, molecules, cells and organisms act, interact, organize or transform themselves. These are often designated in ID literature as unguided natural processes to distinguish them from other processes in which some agent (like ID's intelligent designer) intentionally participates (or "guides" them) to bring about an outcome distinctly different from what would otherwise have happened naturally.
In ID literature all natural processes or causes are presumed to fall into one of three causal categories: 1) chance, 2) necessity, or 3) the joint action of chance and necessity. Natural objects or events that are the outcome of pure chance are products of wholly random phenomena (a fair coin-flipping exercise, for example) with no patterning influences at work, and can best be described in purely statistical terms. Natural objects or events that are the products of necessity are the outcome of deterministic natural laws in which contingency and chance play no effective roles (as in the orbital motion of planets, for example). Most natural objects, however, are the outcome of the joint action of both chance and necessity, with randomness, contingency and deterministic laws each playing some significant role.
For the purposes of his "design-theoretic" analysis, Dembski prefers to treat all three categories at once under the rubric of stochastic processes, a concept that allows for variable contributions of both chance and necessity-from pure randomness to full determinism, and all variations between-in one mathematically convenient formalism. Although the unwary reader might easily be confused, Dembski usually designates this full spectrum of causal possibilities by the label "chance." Throughout most of No Free Lunch, the terms "chance hypothesis" and "chance explanation" do not refer to chance (random events or processes) alone, but must be taken to mean "all hypotheses, postulates and theories concerning the natural causation of events." The comprehensiveness and inclusiveness of these terms must be understood in order to see the extremity of Dembski's numerous claims in No Free Lunch.
Darwinism = evolution + naturalism
Proponents of ID are not in full agreement in their evaluation of the basic vision of biological evolution. Some ID advocates are willing to accept a limited amount of variation and selection but nonetheless balk at the idea that all life forms are related by common ancestry. Evolution limited to small changes (often called microevolution) is often tolerated, as it is even among many young-earth creationists, but the idea of uninterrupted genealogical continuity (or macroevolution) among all life forms over billions of years of earth-history is rejected. Phillip Johnson, for instance, sees the common ancestry thesis as the foundation of Darwinism-the view of life's formational history that he vigorously rejects.
When we posit that the discontinuous groups of the living world were united in the remote past in the bodies of common ancestors, we are implying a great deal about the process by which the ancestors took on new shapes and developed new organs...There may be arguments about the details, but all the basic elements of Darwinism are implied in the concept of ancestral descent.[9]
There are other ID advocates, however, who express a willingness to accept the common ancestry thesis as a real possibility, but insist that the changes that took place over time required more than natural processes alone. Michael Behe, for instance, says
I find the idea of common descent (that all organisms share a common ancestor) fairly convincing, and have no particular reason to doubt it...Although Darwin's mechanism-natural selection working on variation-might explain many things, however, I do not believe it explains molecular life.[10]
And Dembski comments that
...intelligent design is not a form of anti-evolutionism. [On the contrary, intelligent design is] fully compatible with large-scale evolution over the course of natural history, all the way up to what biologists refer to as "common descent."[11]
But-and this is the place where an ID-based curriculum will differ from how biological evolution is currently taught-intelligent design is not willing to accept common descent as a consequence of the Darwinian mechanism. The Darwinian mechanism claims the power to transform a single organism (known as the last common ancestor) into the full diversity of life that we see both around us and in the fossil record. If intelligent design is correct, then the Darwinian mechanism of natural selection and random variation lacks that power.[12]
What all advocates of ID do seem to be agreed on is their judgment that Darwinism is impossible because the Darwinian mechanism is inadequate to accomplish the large-scale transformations envisioned by nearly every professional biologist today. But a reader of ID literature must pay careful attention to the varied operative meanings that these key terms convey. At minimum, Darwinism denotes the concepts of large-scale biological evolution and common descent as consequences of unguided natural processes. But there is usually far more meaning packed into the term as it is employed rhetorically in ID literature. "Darwinism" is commonly employed to characterize biological evolution as a way of accounting for the formational history of life that is both "thoroughly naturalistic" and "nonteleological." But which form of naturalism does "thoroughly naturalistic" entail? If only minimal or methodological naturalism, then a number of theistic worldviews could accommodate it. But if the term Darwinism is presumed to entail maximal naturalism (or scientific naturalism, as Johnson uses the term), then Darwinism effectively becomes a member of the family of atheistic worldviews. This is, I believe, the rhetorical impact most commonly intended in the literature of the ID movement, especially when the reader is offered the binary choice-either Darwinism or design.
Similar concerns must be raised when Darwinism is referred to as a "nonteleological" theory-a concept that excludes reference to goals, purposes or intentions. If this exclusion refers only to individual events or to low level natural processes in isolation from the larger context, that would be consistent with minimal naturalism and open to various forms of theism. But if the characterization of "nonteleological" entails the rejection of purpose or intention at all levels of consideration, then "Darwinism" is once again functioning effectively as a substitute label for "maximal naturalism."[13]
The Darwinian mechanism
The term "Darwinian mechanism" refers, of course, to the menu of relevant natural processes that are presumed by the vast majority of biologists to make biological evolution and common descent possible. Here the key question is, In the judgment of ID advocates, what are the "relevant" natural processes that belong on this list? At minimum, the Darwinian mechanism menu includes genetic variation and natural selection. As Dembski's expresses it, "The Darwinian mechanism consists of random variation, which provides the raw material for Darwinian evolution, and natural selection, which sifts that material."[14] Stating this a bit more positively, I would prefer to say that variation functions as a means for searching a portion of the "possibility space" of viable offspring in the genetic vicinity of the parent organisms, and natural selection (the differential survival of varied offspring lines) functions to move populations of organisms toward "fitness peaks" of maximal reproductive success.
But there may be many more categories of natural processes that have contributed to the success of biological evolution over life's formational history. Would ID proponents place all of these in the category of Darwinian mechanism? Evidently not. For instance, in their evaluation of the proposition that certain "irreducibly complex" biological structures like bacterial flagella were formed by this mechanism, both Behe and Dembski limit their evaluation to gradual processes only, processes that bring about only minute functional improvements (sometimes narrowly constrained to a single function) from generation to generation. According to Behe, for instance, "The key question is this: How could complex biochemical systems be gradually produced?"[15] And in Behe's book, Darwin's Black Box, the index listing for "Darwinian evolution" includes the parenthetical clarification "(gradualism)."
In No Free Lunch, Dembski tells us that "The problem, then, is to coordinate the gradual Darwinian evolution of an organism with the emergence of an irreducibly complex system that the organism now houses but did not always possess."[16] And what about various transformational processes or events that fall outside of a strict gradualism? It seems that they are to be set aside as natural processes that are not relevant to ID's evaluation of the Darwinian mechanism. "Ideas like coordinated macromutations, lateral gene transfer, set-aside cells, and punctuated saltational events are thoroughly non-Darwinian."[17] But the real question, it seems to me, is this: Whether these and other such events are considered to fall within the bounds of a strict gradualist definition of the "Darwinian mechanism" or not, are they relevant to the formational history of life on earth? The development of novel biotic structures is no respecter of the labels that we might choose to pin on the various factors contributing to their actualization.
Another restriction on the menu of relevant natural processes considered by Dembski as legitimate contributors to the Darwinian mechanism arises from his requirement that scientific explanations regarding evolutionary processes must be causally specific. In Dembski's words, "Causal specificity means specifying a [natural] cause sufficient to account for the effect in question."[18] "Lack of causal specificity leaves one without the means to judge whether a transformation can or cannot be effected."[19]
Full causal specificity is, of course, the goal of all scientific explanations, but it is often very difficult to achieve, especially in the reconstruction of life's formational history. That's just a fact of life in evolutionary biology, as well as in many other areas of science. What, then, should biology do? Abandon its search for natural causes? Open the door to hypotheses regarding non-natural causation? Posit the possibility of occasional form-conferring interventions by an unembodied intelligent agent? Yes, says Dembski. In effect, that is the ID proposal. After noting that science-"when biased by naturalism"-tends to restrict its search for explanations to purely natural causes, Dembski argues: "But in the absence of causal specificity, there is no reason to let naturalism place such restrictions on our scientific reasoning."[20]
I suppose that one could grant the possibility that this last point is technically correct, but one could equally well argue that there are good reasons-scientific, philosophical, and theological-why most of us do find positing the sufficiency of natural causes to be warranted. Regardless of that, however, a serious problem is introduced into Dembski's analysis when full causal specificity is taken to be a requirement for natural causes to be relevant contributions to the Darwinian mechanism. Many scientific hypotheses regarding the manner in which various transformational processes may have contributed to the actualization of some new biotic structure might fall short of full causal specificity-even though they may be highly plausible applications of mechanisms that are at least partially understood. When that is the case, the ID approach tends to denigrate them as nothing more than "just-so stories" and to remove them from further consideration.[21] If these scientific hypotheses do not exhibit sufficient causal specificity to allow the computation of a numerical probability for success, then they are likely to be dismissed from ID's consideration. Only those mechanisms that are now fully understood, it seems, can be placed on the menu of relevant natural processes contributing to the Darwinian mechanism.
Three effects of this full causal specificity requirement are easy to identify: (1) There are now numerous biotic structures for which science is unable to formulate causally specific (detailed and complete) accounts of their actualization; (2) In the absence of the causal specificity that it demands of scientific explanations (but not of intelligent design explanations) the ID movement has opportunity to posit its non-natural, intelligent design explanations as alternatives; and (3) Each time a new causally specific scientific explanation for one of these biotic structures is developed, the ID explanation for its actualization becomes superfluous.[22]
NOTES:
1 William A. Dembski, No Free Lunch: Why Specified Complexity Cannot Be Purchased Without Intelligence (Lanham, MD: Rowman & Littlefield Publishers, Inc., 2002). Future references to this work will be designated simply as NFL, p. xyz.
2 NFL, p. 355.
3 NFL, pp. 331-332.
4 This essay focuses on the ID movement's principal scientific claim and the rhetorical strategies employed to support it. I also have expressed concern for some of the religious and theological implications of ID's concept of divine creative action. For examples of this critique, see "Intelligent Design: A Celebration of Gifts Withheld?" published as a chapter in the book, Darwinism Defeated? The Johnson-Lamoureux Debate on Biological Origins, Denis O. Lamoureux, Phillip E. Johnson, et al. (Vancouver: Regent College Publishing, 1999); "Science & Christianity as Partners in Theorizing," published as a chapter in the book, Science & Christianity: Four Views, Richard F. Carlson, ed. (Downers Grove, IL: InterVarsity Press, 2000); "The Creation: Intelligently Designed or Optimally Equipped?" published in the journal Theology Today, October, 1998, pp. 344-364; and "Does Intelligent Design Have a Chance?" published in the journal Zygon, Vol 34, No. 4, December, 1999, pp. 667-675.
5 I am indebted to David Ray Griffin for the terminology of maximal naturalism and minimal naturalism and the way in which this distinction proves helpful in discussions of this sort. See his book, Religion and Scientific Naturalism: Overcoming the Conflicts (Albany: SUNY Press, 2000), for further development of this terminology and its application to the relationship of science and religion.
6 NFL, p. 367.
7 Phillip E. Johnson, Darwin on Trial (Downers Grove, IL: InterVarsity Press, 1991), p. 115.
8 NFL, p. 372n4.
9 Darwin on Trial, p. 150.
10 Michael J. Behe, Darwin's Black Box: The Biochemical Challenge to Evolution (New York: The Free Press, 1996), p. 5.
11 NFL, p. 314.
12 NFL, pp. 314-315.
13 In anti-evolutionist literature it is often implied that the presence of randomness in natural processes such as random variation or natural (unguided) selection completely displaces the idea of goals, purposes or intentions. But that is simply not the case. Although the idea that each individual event in evolutionary history is purposefully intended or in conformity to some predetermined plan may have to be set aside, that does not at all eliminate the possibility that the evolutionary process as a whole might well be serving some comprehensive purpose. As an illustration, suppose there were a completely honest gambling casino in which pure randomness characterized every roll of the dice, every spin of the wheel, every turn of the card, etc. Nonetheless, the casino accomplishes its purpose of bringing a handsome profit to the bank at the end of each day. In fact, the owners of the casino depend on authentic randomness in their computation of payout rates in order to accomplish their goal of making a profit. Randomness at one level does not exclude purpose at another. Randomness can be purposefully employed.
14 NFL, p. 286.
15 Darwin's Black Box, p. 34.
16 NFL, p. 286.
17 NFL, p. 287.
18 NFL, p. 240.
19 NFL, p. 242.
20 NFL, p. 244
21 According to Dembski, "Darwinian just-so stories have no more scientific content than Rudyard Kipling's original just-so stories about how the elephant got its trunk or the giraffe its neck." NFL, p. 368.
22 See NFL, p. 364, for Dembski's acknowledgment of this. "Even if the Darwinian mechanism could be shown to do all of the design work for which design theorists want to invoke intelligent causation (say for the bacterial flagellum and systems like it) a design-theoretic framework would not destroy any valid findings of science. To be sure, design would then become a largely superfluous component of this framework...."