The commitment to methodological naturalism that Lewontin describes, as well as the behavior of scientists in cases such as Sternberg’s, leave no doubt that many in science simply will not consider the design hypothesis as an explanation for the Cambrian explosion or any other event in the history of life, whatever the evidence. To do so would be to violate the “rules of science” as they understand them.
But Is It Science?
But are these scientists right? Perhaps science must limit itself to purely naturalistic or materialistic explanations. If so, are there perhaps good reasons for excluding the design hypothesis from consideration as a scientific hypothesis? Is methodological naturalism the correct policy for science?
Though scientists routinely assert methodological naturalism as a scientific norm, that principle and its exclusion of the design hypothesis have proven difficult to justify. To claim that a specific theory does not qualify as scientific requires a definition of science or a set of definitional criteria by which to make that kind of a judgment. Some philosophers and scientists have asserted that for a scientific theory to qualify as scientific, it must meet various criteria of testability, falsifiability, observability, repeatability, and the like. Philosophers of science call these “demarcation criteria,” because some scientists purport to use them to define or “demarcate” science and to distinguish it from pseudo science or from other forms of inquiry such as history, religion, or metaphysics.13
The General Problem of Demarcation
The demarcation question has long been a vexing one. Historically, scientists and philosophers of science have thought that science could be distinguished by its especially rigorous method of study. But attempts to define science by reference to a distinctive method have proven problematic because different branches and types of science use different methods.
For example, some scientific disciplines distinguish and classify natural entities, while others attempt to formulate overarching laws that apply to all entities. Some disciplines perform laboratory experiments under controlled and replicable conditions, while others attempt to reconstruct or explain singular events in the past, often based on field studies of evidence or clues rather than laboratory experiments. Some disciplines generate mathematical descriptions of natural phenomena without positing mechanisms to explain them. Others look for mechanisms or explain law-like regularities by reference to underlying mechanisms. Some scientific disciplines make predictions to test theories, while others test competing theories by comparing their explanatory power. Some disciplines use both these methods, while some conjectures (particularly in theoretical physics) may not be testable at all. And on it goes.
An episode in the history of science illustrates the problem. During the seventeenth century, a group of scientists called the “mechanical philosophers” insisted, based largely on advances in early chemistry, that scientific theories must provide mechanistic explanations. Such explanations had to involve one material entity pushing or pulling another. Yet in physics, Isaac Newton (1642–1727) formulated an important theory that provided no mechanistic explanation. His theory of universal gravitation described mathematically, but did not explain in a mechanistic way, the gravitational attraction between planetary bodies—bodies separated from each other by miles of empty space with no means of mechanical interaction with each other whatsoever.14 Despite provocation from the German mathematician Gottfried Wilhelm Leibniz (1646–1716), who defended the mechanistic ideal, Newton expressly refused to give any explanation, mechanistic or otherwise, for the mysterious “action at a distance” that his theory described.15
Did that make Newton’s theory unscientific? Strictly speaking, the answer depends upon which definition of science someone chooses to apply. Today one would be hard-pressed to find anybody who denies that Newton’s famous theory qualified as scientific. Yet we could easily find scientists still willing to say scientific theories must provide mechanisms as well as others who would deny as much.
And that is the problem. If scientists and philosophers of science do not have an agreed-upon definition of science, how can they settle questions about which theories do and do not qualify as scientific? If scientists lack such a definition, it’s difficult to argue that any particular theory is unscientific by definition. For this reason, philosophers of science, the scholars who study the nature and definition of science, now almost universally reject the use of demarcation arguments to decide the validity of theories or settle competition between them.16 They increasingly regard demarcation as an essentially semantic question and nothing more. Is theory X scientific or not? Answer: that depends upon which definition of science is used to decide the question.
Moreover, as the philosopher of science Larry Laudan has shown in a seminal article, “The Demise of the Demarcation Problem,” attempts to apply demarcation criteria to decide the scientific status of specific theories have invariably generated irreconcilable contradictions.17 The vortex theory of gravity that Newton’s theory replaced envisioned planets swirling around the sun pushed by a substance called ether.18 It did provide a mechanistic explanation for gravitational attraction. It failed, however, to explain the evidence and was judged by Newton and physicists following him to be manifestly false. Nevertheless, because it proposed a mechanistic cause of gravitation, it qualified as “scientific”—at least given the conception of science favored by Leibniz and the mechanical philosophers.19 Conversely, Newton’s theory failed to as scientific by their definition, though it much more accurately fit the evidence.
Such contradictions have long beset the whole enterprise of demarcation. Theories that scientists have rejected as false because of their inability to explain or describe the evidence often meet the very criteria or methodological features (testability, falsifiability, repeatability, observability, etc.) that allegedly characterize true science. On the other hand, many highly esteemed or successful theories often lack allegedly necessary features of genuine science.
Thus, philosophers of science generally think it much more important to assess whether a theory is true, or whether the evidence supports it, than whether it should or should not be classified as “science.” The question of whether a theory is “scientific” is really a red herring. What we really want to know is whether a theory is true or false, supported by the evidence or not, worthy of our belief or not. And we cannot decide those questions by applying a set of abstract criteria that purport to tell in advance what all good scientific theories must look like.20
Define and Dismiss: Demarcation Arguments Against Intelligent Design
The rejection of demarcation arguments among philosophers of science has not stopped critics of intelligent design from attempting to settle debates about biological origins by the expedient of formulating such arguments against intelligent design. Some use these arguments to justify methodological naturalism (which has the same effect).
Advocates of methodological naturalism have argued that the theory of intelligent design is inherently unscientific for some, or all, of the following reasons: (a) is not testable,21 (b) is not falsifiable,22 (c) does not make predictions,23 (d) does not describe repeatable phenomena, (e) does not explain by reference to natural law,24 (f) does not cite a mechanism,25 (g) does not make tentative claims,26 and (h) has no problem-solving capability.27 They have also claimed that it is not science because it (i) refers to an unobservable entity.28 These critics also assume, imply, or assert that materialistic evolutionary theories do meet such criteria of proper scientific method.
Readers may wish to consult Signature in the Cell for a more detailed response to these specific arguments. There I show that many of these claims are simply false (e.g., contrary to the claims of its critics intelligent design is testable; it does make predictions; it does formulate its claims tentatively; and it does have scientific problem-solving capability). But I also show that when the claims of those making demarcation arguments are true—when intelligent design doesn’t meet a specific criterion
—that fact does not provide good reason for excluding intelligent design from consideration as a scientific theory. Why? Because the materialistic evolutionary theories that intelligent design challenges, theories widely regarded by convention as “scientific,” fail to meet the very same demarcation standard. In other words, there is no defensible definition of science, and no specific demarcation criterion, that justifies both excluding intelligent design from science and including competing materialistic evolutionary theories. Instead, attempts to use demarcation criteria specifically to disqualify intelligent design as a scientific theory have repeatedly failed to differentiate the scientific status of intelligent design from that of competing theories. Depending upon which criteria are used to adjudicate their scientific status, and provided metaphysically neutral criteria are selected to make such assessments, intelligent design and materialistic origins theories invariably prove equally scientific or unscientific.
For example, some critics of intelligent design have argued that it fails to qualify as a scientific theory because it makes reference to an unseen or unobservable entity, namely, a designing mind in the remote past. Yet many accepted theories—theories assumed to be scientific—postulate unobservable events and entities. Physicists postulate forces, fields, and quarks; biochemists infer submicroscopic structures; psychologists discuss their patients’ mental states. Evolutionary biologists themselves infer unobserved past mutations and invoke the existence of extinct organisms and transitional forms for which no fossils remain. Such things, like the actions of an intelligent designer, are inferred from observable evidence in the present, because of the explanatory power they may offer.
If the demarcation criterion of observability is applied rigidly, then both intelligent design and materialistic theories of evolution fail to qualify as scientific. If the standard is applied more liberally (or realistically)—acknowledging the way in which historical scientific theories often infer unobservable past events, causes, or entities—then both theories qualify as scientific.
And so it goes with other such criteria as well. There is no specific (non-question-begging) demarcation criterion that succeeds in disqualifying the theory of intelligent design from consideration as a scientific theory without also doing the same to its materialistic rivals.
Reasons to Regard Intelligent Design as a Scientific Theory
Demarcation arguments fail to justify excluding intelligent design from science. But it turns out that there are some good—if convention-dependent—reasons to regard intelligent design as a scientific theory.
For example, many scientists and philosophers of science regard testability as an important feature of scientific inquiry. And intelligent design is testable in three specific and interrelated ways. First, like other scientific theories concerned with explaining events in the remote past, intelligent design is testable by comparing its explanatory power with that of competing theories. Second, intelligent design, like other historical scientific theories, is tested against our knowledge of the cause-and-effect structure of the world. As we have discussed, historical scientific theories provide adequate explanations when they cite causes that are known to produce the effects in question or “causes now in operation.”29 Because of this, the plausibility of historical scientific theories, including intelligent design, can be tested by reference to independent knowledge of cause-and-effect relationships. Third, although historical scientific theories typically cannot be tested under controlled laboratory conditions, they do sometimes generate predictions that enable scientists to compare their merit to that of other theories. Intelligent design has generated a number of specific empirical predictions that distinguish it from competing evolutionary theories and that serve to confirm the design hypothesis over its competitors. (In Signature in the Cell, I described ten such predictions that the theory of intelligent design has generated).30
There is another compelling, if convention-dependent, reason to regard intelligent design as a scientific theory. The inference to intelligent design is based upon the same method of historical scientific reasoning and the same uniformitarian principles that Charles Darwin used in On the Origin of Species. The similarity in logical structure runs quite deep. Both the argument for intelligent design and the Darwinian argument for descent with modification were formulated as abductive inferences to the best explanation. Both theories address characteristically historical questions; both employ typically historical forms of explanation and testing; and both have metaphysical implications. Insofar as we regard Darwin’s theory as a scientific theory, it seems appropriate to designate the theory of intelligent design as a scientific theory as well.
Indeed, neo-Darwinism and the theory of intelligent design are not two different kinds of inquiry, as some critics have asserted. They are two different answers—formulated using a similar logic and method of reasoning—to the same question: “What caused biological forms and the appearance of design to arise in the history of life?” It stands to reason that if we regard one theory, neo-Darwinism or intelligent design, as scientific, we should regard the other as the same. Of course, whether either theory is true or not is another matter. An idea may be scientific and incorrect. In the history of science, many theories have proven to be so. The vortex theory of gravity, to which I referred earlier, would be one of nearly countless illustrations.
For readers who would like to consider more detailed responses to arguments about whether intelligent design qualifies as “science,” I recommend Chapters 18 and 19 in Signature in the Cell.31 In Signature, I respond in detail to other philosophical objections to the case for intelligent design. These include challenges such as: (a) intelligent design is religion, not science,32 (b) the case for intelligent design is based on flawed analogical reasoning, (c) intelligent design is a fallacious argument from ignorance, sometimes called the “God of the Gaps” objection, (d) intelligent design is a science stopper, (e) the famous zinger, popularized by Richard Dawkins, that asks “Who designed the designer?”33 and many others.
A New Objection to the Scientific Status of Intelligent Design
Since the publication of Signature in the Cell, Robert Asher, a University of Cambridge paleontologist, has offered another reason to contest my characterization of intelligent design as a scientific theory. In his book, Evolution and Belief, he challenges my claim to have used the uniformitarian method of Lyell and Darwin to develop the case for intelligent design. Since his objection is new, published only in 2012 by Cambridge University Press, it deserves discussion.
Asher characterizes my thinking as follows: “The processes we know and observe today are relevant to explaining the phenomena of the past, and we know that particularly complicated things we see today have an intelligence behind them.”34 He notes that I argue certain complex technologies, such as computer software, have “only one source: human ingenuity.”35 It follows, according to Asher’s paraphrase of my argument that “a similarly complex device we observe in the geological past must also have arisen as a result of something like human ingenuity, i.e., intelligence.”36
Asher doesn’t seem to understand the importance of specified information, as opposed to “complicated things,” as a key indicator of design. That aside, he does claim to recognize the role of uniformitarian principles of reasoning in my argument for intelligent design. In spite of this, Asher elsewhere disputes that I employ the uniformitarian method of reasoning. Why? According to Asher, the inference to intelligent design is actually “anti-uniformitarian” because it doesn’t provide a “mechanism.” As he puts it, “by attempting to replace a causal mechanism (natural selection) with an attribution of agency (design), ID advocates such as Meyer are decidedly anti-uniformitarian. What process of today could possibly lead to his understanding of the past?”37
The answer to Asher’s question seems pretty obvious. The answer is: intelligence. Conscious activity. The deliberate choice of a rational agent. Indeed, we have abundant experience in the present of intelligent
agents generating specified information. Our experience of the causal powers of intelligent agents—of “conscious activity” as “a cause now in operation”—provides a basis for making inferences about the best explanation of the origin of biological information in the past. In other words, our experience of the cause-and-effect structure of the world—specifically the cause known to produce large amounts of specified information in the present—provides a basis for understanding what likely caused large increases in specified information in living systems in the past. It is precisely my reliance on such experience that makes possible an understanding of the type of causes at work in the history of life. It also makes my argument decidedly uniformitarian—not “anti-uniformitarian”—in character.
Asher confuses the uniformitarian imperative in historical scientific explanations (the need to cite a presently known or adequate cause) with a demand for citing a material cause, or mechanism. The theory of intelligent design does cite a cause, and indeed one known to produce the effects in question, but it does not necessarily cite a mechanistic or materialistic cause. Proponents of intelligent design may conceive of intelligence as a strictly materialistic phenomenon, something reducible to the neurochemistry of a brain, but they may also conceive of it as part of a mental reality that is irreducible to brain chemistry or any other physical process. They may also understand and define intelligence by reference to their own introspective experience of rational consciousness and take no particular position on the mind-brain question.
Asher assumes that intelligent design denies a materialistic or “physicalist” account of the mind (as I personally do, in fact) and rejects it as unscientific on that basis. But he offers no noncircular reason for making that judgment. He cannot say that the principle of methodological naturalism requires that all genuinely scientific theories invoke only mechanistic causes, because the principle of methodological naturalism itself needs justification. And asserting that “all genuinely scientific theories must provide mechanisms” is just to restate the principle of methodological naturalism in different words. Indeed, to say that all scientific explanations must provide a mechanism is equivalent to saying that they must cite materialistic causes—precisely what the principle of methodological naturalism asserts. Asher seems to be assuming without justification that all scientifically acceptable causes are mechanistic or materialistic. His argument thus assumes a key point at issue, which is whether there are independent—that is, metaphysically neutral—reasons for requiring historical scientific theories to cite materialistic causes in their explanations as opposed to explanations that invoke possibly immaterial entities such as creative intelligence, mind, mental action, agency, or intelligent design.
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