I appreciate the close reading and careful evaluation of my book, Darwin’s Doubt (DD) by the authors of the multi-part review series published recently on the BioLogos website. I would like to thank the main reviewers of the book (Ralph Stearley, Robert Bishop, and Darrel Falk) for taking the time to read and review the book as well as BioLogos and its new President Deborah Haarsma for their decision to highlight these reviews and their generous invitation to me to submit this response. Anyone whose work receives such scrutiny, with such a breadth of coverage, will learn something, and I certainly have.
I have especially appreciated how the reviews in this recent series have unexpectedly clarified the nature of disagreement between proponents of the theory of intelligent design (ID) and the proponents of theistic evolution (or evolutionary creation) associated with BioLogos. I—and many others—have long assumed that the debate between our two groups was mainly a scientific debate about the adequacy of contemporary evolutionary theory. Surprisingly, the reviews collectively have shown that the main disagreement between ID proponents and BioLogos is not scientific, but rather philosophical and methodological.
In particular, the reviews have revealed that the central issue dividing the BioLogos writers from intelligent design (ID) theorists concerns a principle known as methodological naturalism (MN). MN asserts that scientists must explain all events and phenomena by reference to strictly naturalistic or materialistic causes. The principle forbids postulating the actions of personal agency, mind, or intelligent causation in scientific explanations and thus limits the explanatory toolkit of science to strictly material processes or physical causes. The principle of methodological naturalism is, of course, not a scientific theory nor an empirical finding, but an allegedly normative methodological rule, against which I have argued in depth, both in Darwin’s Doubt (see Chapter 19) and in my earlier book, Signature in the Cell (see Chapters 18 and 19). My colleagues have also argued against MN in their responses to some of the BioLogos reviews of Darwin’s Doubt (see, for example, here and here).
Recall that Darwin’s Doubt argues that intelligent design provides the best explanation for the origin of the genetic (and epigenetic) information necessary to produce the novel forms of animal life that arose in the Cambrian period. In making this case, I show first that neither the neo-Darwinian mechanism of natural selection acting on random mutations, nor more recently-proposed mechanisms of evolutionary change (species selection, self-organization, neutral evolution, natural genetic evolution, etc.—see Darwin’s DoubtChapters 15-16) are sufficient to generate the biological information that arises in the Cambrian period. Instead, I show—based upon our uniform and repeated experience—that only intelligent agents have demonstrated the power to generate the kind of functional information that is present in biological systems (and that arises with the Cambrian animals). Thus, I conclude that the action of a designing intelligence provides the best (“most causally adequate”) explanation for the origin of that information.
Now, one might have expected that Ralph Stearley, a paleontologist, and Darrel Falk, a geneticist, both of whom have extensive knowledge of evolutionary theory, would have critiqued the main scientific argument of Darwin’s Doubt on scientific grounds. In particular, one might have expected that they would have argued that either the neo-Darwinian mechanism, or some other evolutionary mechanism, does have the creative power to produce the information necessary to build new forms of animal life. Instead, except for raising a few minor objections about incidental scientific matters, both acknowledged that evolutionary theory has left the problem of the Cambrian explosion unsolved—i.e., that the mutation/natural selection mechanism lacks the creative power to account for macro-evolutionary innovations in the history of life.
Falk, for instance, wrote that Darwin’s Doubt identifies “one of the great mysteries in evolutionary biology today,” namely, the origin of animal form. Falk observed that this problem has never really been addressed by neo-Darwinian theory, and reflected on his own experiences as a college teacher of evolution discovering the shortcomings of textbook theory when confronted with the origin of complex animal evolution. He added that the process of natural selection, important as it may be in certain contexts, is not the “driving mechanism” of macro-evolutionary change, and thus, that the mystery of the Cambrian explosion still awaits a solution.
Of course, Falk himself rejects my proposed solution and my positive argument for intelligent design as the best explanation for what I call the “Cambrian information explosion.” He contends that any such inference to intelligent design is “premature.” Nevertheless, Falk doesn’t really offer any evidence or scientific reason for rejecting the positive argument of Darwin’s Doubt. Indeed, it would be difficult for him to deny that intelligent agents possess the causal power to produce functional information. Is it possible, then, that his reluctance to consider intelligent design as the best or “most causally adequate” explanation stems from a tacit commitment to methodological naturalism? If inferences to intelligent design are perceived as breaking the rules of science then, of course, they will always be seen as “premature.”
Stearley also found value in the book’s scientific analysis, saying that the book “makes an argument that folks should think hard about” and indeed that he “resonate[s] with some of Meyer’s arguments.” Although he was unhappy with aspects of DD’s treatment (he thinks I should have talked more about the small shelly fossils in the early Cambrian, for example—something my colleagues and I have already addressed in responses to critics here and here), Stearley agreed with my critique of the adequacy of current evolutionary mechanisms for the origin of animal form. Thus, Stearly notes that I had “developed a case for the inadequacy” of standard approaches. On scientific grounds, therefore, relatively little of note separates us. In fact, Stearley admitted that he was “inclined to see design in nature,” but he too demurred from affirming the design hypothesis, offering hesitant uncertainty in response to my positive case. Could it be that in Stearley’s reluctance, we may, again, be seeing a tacit commitment to methodological naturalism?
Of the three reviewers, Wheaton College philosopher of science Robert Bishop was the least persuaded by DD’s arguments—but, interestingly, he was also the most explicitly committed to the principle of methodological naturalism. Indeed, he objected to the thesis of the book precisely because it openly rejects (and violates) the principle of methodological naturalism.
Consequently, his four-part critique, by far the longest in the BioLogos series, said very little about my scientific arguments. (He did argue that I was wrong to claim that newer models of evolutionary theory represent significant deviations from neo-Darwinian orthodoxy. Yet, notably, biologist Darrel Falk’s review affirmed my assessment of these newer theories over and against Bishop’s.) In any case, Bishop focused his critique on what he called my “rhetorical strategies,” giving particular attention to philosophical issues concerning the legitimacy of design inferences in biology.
In Bishop’s judgment, intelligent design flagrantly violates the rule of methodological naturalism—a rule that he regards as normative for the practice of all natural science because he believes (incorrectly, as it turns out) that “methodological naturalism is the way scientific investigation has been done since before the time of the Scientific Revolution.” Indeed, as my colleague Paul Nelson pointed out in his response to Bishop’s critique, Bishop badly misreads the history of science. The design arguments developed by Isaac Newton—in the Opticksand the Principia, for instance —alone contradict Bishop’s claims.
Even so, Bishop correctly notes that methodological naturalism does categorically exclude consideration of inferences to the activity of non-physical entities or causes (i.e., intelligent agents or minds) in evolutionary or historical biology. These fields simply do not allow reference to the activity of intelligent agents. Bishop appears to justify this prohibition by claiming that “an intelligent agent is a presupposition external to cellular and evolutionary biology; intelligence has to be brought in from the outside”—a move that, in his view, would transgress the boundaries of natural science and that “biologists rightly object to.”
Of course, asserting that methodological naturalism prohibits design inferences and then justifying that prohibition by arguing that inferring intelligent design would transgress the boundaries of science as determined by methodological naturalism is to argue in a circle. Further, as Paul Nelson pointed out:
Bishop completely misunderstands the basis of Meyer’s case for intelligent design. True, the intelligent agency that Meyer invokes to explain the origin of the information present in animal forms is “external” to the present operation of cells in those animals, just as the intelligence responsible for the design of a laptop computer is external to it. But that does not mean that Meyer “presupposes” that an agent “external to cellular and evolutionary biology” caused the origin of the information that arose in the Cambrian explosion of animal life. Instead, Meyer infers that a designing intelligence external to the features of cells and animals generated that information and he does so based upon our knowledge of cause and effect and [the] information-rich structures present in living systems. Since, as he argues, intelligence or mental activity is the only known cause of the origin of large amounts of functional or specified information, especially when that information is found in a digital form, the origin of the enormous amount of specified information that arose in the Cambrian period is best explained by the activity of a designing intelligence. Intelligence is not presupposed; it is inferred based upon what we know about the cause, indeed the only known cause, of specified information.
In any case, by focusing his critique on the allegedly normative status of methodological naturalism, and DD’s repudiation of that methodological convention as a normative rule for science, Bishop did not focus his critique on the scientific claims or analysis of the book.
Thus, both Bishop’s review (which challenged the methodological approach, but not the scientific analysis, of the book), and Falk and Stearley’s reviews (both of which conceded my main scientific critique of evolutionary theory) have helped to clarify the true nature of our disagreement. Since I look forward to further dialogue with our colleagues at BioLogos, I regard these reviews as a constructive first step to further discussion of the key issues that separate us.
As we continue to our discussion, I hope we can address the central issue about which we disagree. As noted, I have developed a detailed critique of methodological naturalism in my published work. I have shown, for example, that the demarcation criteria typically offered as justifications for methodological naturalism invariably fail to distinguish the scientific status of intelligent design and competing evolutionary theories. I have also argued that the principle of methodological naturalism restricts the intellectual freedom of scientists and compels them to elect materialistic explanations, whatever the evidence may indicate. As such, I argue that the principle impedes the truth-seeking (as opposed to convention-following) function of science.
Given my own skepticism about methodological naturalism, I would very much like to know what Darrel Falk and Ralph Stearley think about the principle and its alleged status as rule governing scientific reasoning. Their reviews express hints that design inferences in historical biology might be acceptable to them—yet those same reviews reveal a deep ambivalence about challenging the naturalistic premises of current evolutionary theory, or more fundamentally, about challenging MN itself.
Unfortunately, methodological naturalism is a demanding doctrine. The rule does not say “try finding a materialistic cause but keep intelligent design in the mix of live possibilities, in light of what the evidence might show.” Rather, MN tells you that you simply must posit a material or physical cause, whatever the evidence. One cannot discover evidence of the activity of a designing mind or intelligence at work in the history of life because the design hypothesis has been excluded from consideration, before considering the evidence, by the doctrine of methodological naturalism (and the definition of science that follows from it).
Nevertheless, having a philosophical rule dictate that one may not infer or posit certain types of causes, whatever the evidence, seems an exceedingly odd way for science to proceed. Scientists tend to be realists about the power of evidence, but skeptics about philosophical barriers—which, if it is anything, the rule of MN surely is. Placing the detection of intelligent design out of the reach of scientific investigation, before the evidence has had a chance to instruct us, looks like rigging a game before any players have taken the field.
In the debate about intelligent design, MN has compelled many scientists to dismiss evidence for intelligent agency as an explanation for phenomena such as increases in large functional digital information, that are known to be produced by one—and only one—kind of cause, namely, intelligent activity. Proponents of intelligent design reject this restriction precisely because it compromises the truth-seeking function of science. We insist that scientists should seek the best explanation, based upon our knowledge of the evidence and the causal powers of competing explanatory entities, not seek the best explanation only among an artificially restricted set of options. Our BioLogos colleagues appear to disagree.
This is the remaining issue, and it won’t be easy to resolve, because unlike scientific disputes where new evidence can break an impasse, MN keeps the evidence itself out of the discussion. Yet, in our view, if ever a rule of method deserved to be tossed onto the rubbish heap of history, now is the time for MN to be sent in that direction. Natural science has nothing to fear from allowing scientists to consider evidence for design hypotheses because (given the general cultural climate) their rigorous testing is assured, as the vigorous attacks on notions such as “irreducible complexity” and “specified complexity” over the past two decades have already shown. Many scientists have attempted to burnish their scientific standing by publishing challenges to claims made by proponents of intelligent design.
In a similar vein, as we continue our discussion, I would invite our colleagues at BioLogos to engage and reply to our critique of the principle of methodological naturalism—to defend, rather than just assert (as even Bishop mainly did), the normative status of MN. Offering such a defense will doubtless afford further opportunities for clarification and discussion of the key issues.
Constructive dialogue between parties with significant disagreements can, in the best case, expose both common ground and the true nature of those disagreements. The reviews recently published on the BioLogos website, have done both—a fact for which I, as the author of the book under discussion, am genuinely grateful.
About the author
If you enjoyed this article, we recommend you check out the following resources:
David Brooks | To See and Be Seen
Jessica Moerman | No Act Too Small