Does Darwin's Doubt Commit the God-of-the-Gaps Fallacy?
In my previous discussion (here and here) of Charles Marshall's review in Science of my book Darwin's Doubt,1 I responded to Marshall's claim that building Cambrian animals would not have required large amounts of new genetic information, but instead could have been produced by "rewiring" of preexisting developmental gene regulatory networks.2 I showed that Marshall's proposal for "rewiring" gene regulatory networks would itself require an infusion of new information into the biosphere and that Marshall had, in any case, merely pushed the problem of the origin of genetic information back several tens or hundreds of millions of years by presupposing a pre-existing set of genes for building the Cambrian animals in some hypothetical Precambrian ancestor.
I turn now to his claim that the book's argument for intelligent design represents a purely negative "god-of-the-gaps" argument.3 Marshall claims in his review:
Meyer's scientific approach is purely negative. He argues that paleontologists are unable to explain the Cambrian explosion, thus opening the door to the possibility of a designer's intervention. This, despite his protest to the contrary, is a (sophisticated) "god of the gaps" approach, an approach that is problematic in part because future developments often provide solutions to once apparently difficult problems.
I appreciate Marshall's compliment about the sophistication with which I allegedly marshal this fallacious form of argumentation. Nevertheless, his characterization of my argument is entirely inaccurate. First, although I do acknowledge in the last chapter of Darwin's Doubt that the case for intelligent design has implications that are friendly to theistic belief (since all theistic religions affirm that the universe and life are the product of a designing intelligence), the scientific argument that I make does not attempt to establish the existence of God. Instead, I attempt merely to show that key features of the Cambrian animals (and the pattern of their appearance in the fossil record) are best explained by a designing intelligence -- a conscious rational agency or a mind -- of some kind. Thus, my argument does not qualify as a God-of-the-gaps argument for the simple reason that the argument does not attempt to establish the existence of God.4
But let's set aside what Marshall might regard as a trivial distinction about what I claim -- or rather don't claim -- to have established about the identity of the designing intelligence responsible for life. By claiming that my approach is a purely negative one based solely upon "gaps" in our knowledge or in the evolutionary account of the Cambrian explosion, Marshall implies that Darwin's Doubt makes a fallacious kind of argument known to logicians as an "argument from ignorance." Arguments from ignorance occur when evidence against a proposition X is offered as the sole (and conclusive) grounds for accepting some alternative proposition Y. Arguments from ignorance make an obvious logical error. They omit a necessary kind of premise, a premise providing positive support for the conclusion, not just negative evidence against an alternative conclusion. In an explanatory context, arguments from ignorance have the form:
Premise One: Cause X cannot produce or explain evidence E.
Conclusion: Therefore, cause Y produced or explains E.
Critics of intelligent design often claim that the case for intelligent design commits this fallacy.5 They claim that design advocates use our present ignorance of any materialistic cause of specified or functional information (for example) as the sole basis for inferring an intelligent cause for the origin of such information in biological systems. For example, Michael Shermer represents the case for intelligent design as follows: "Intelligent design ... argues that life is too specifically complex (complex structures like DNA) ... to have evolved by natural forces. Therefore, life must have been created by. . . an intelligent designer." In short, Shermer claims that ID proponents argue as follows:
Premise: Materialistic causes or evolutionary mechanisms cannot produce novel biological information.
Conclusion: Therefore, an intelligent cause produced specified biological information.
Marshall echoes Shermer's criticism. But the inference to design as developed in Darwin's Doubt does not commit this fallacy. True, the book does offer several evidentially based (and mathematically rigorous) arguments against the creative power of the mutation/natural selection mechanism (none of which Marshall refutes). And clearly, this lack of knowledge of any adequate materialistic evolutionary cause of, for example, the biological information necessary to produce novel forms of animal life, does provide part of the grounds for the inference to intelligent design presented in Darwin's Doubt. (However, it is probably more accurate to characterize this "absence of knowledge" as knowledge of inadequacy, since it derives from a thorough assessment of causal powers -- and limitations -- of various materialistic evolutionary mechanisms). In any case, the argument presented in the book is not, as Marshall claims, a "purely negative" and, therefore, fallacious argument based on the inadequacy of various materialistic evolutionary mechanisms (or gaps in our knowledge).
Instead, the book makes a positive case for intelligent design as an inference to the best explanation for the origin of the genetic (and epigenetic) information necessary to produce the first forms of animal life (as well as other features of the Cambrian animals such as the presence of genetic regulatory networks that function as integrated circuits during animal development). It advances intelligent design as the best explanation not only because many lines of evidence now cast doubt on the creative power of unguided evolutionary mechanisms, but also because of our positive, experience-based knowledge of the powers that intelligent agents have to produce digital and other forms of information as well as integrated circuitry. As I argue in Chapter 18 of Darwin's Doubt:
Intelligent agents, due to their rationality and consciousness, have demonstrated the power to produce specified or functional information in the form of linear sequence-specific arrangements of characters. Digital and alphabetic forms of information routinely arise from intelligent agents. A computer user who traces the information on a screen back to its source invariably comes to a mind -- a software engineer or programmer. The information in a book or inscription ultimately derives from a writer or scribe. Our experience-based knowledge of information flow confirms that systems with large amounts of specified or functional information invariably originate from an intelligent source. The generation of functional information is "habitually associated with conscious activity." Our uniform experience confirms this obvious truth.6
Thus, the inadequacy of proposed materialistic evolutionary causes or mechanisms forms only part of the basis of the argument for intelligent design. We also know from broad and repeated experience that intelligent agents can and do produce information-rich systems and integrated circuitry. We have positive experience-based knowledge of a cause sufficient to generate new specified information and integrated circuitry, namely, intelligence. We are not ignorant of how information or circuitry arises. We know from experience that conscious, rational agents can create such information-rich structures and systems. To again quote information theorist Henry Quastler: "creation of new information is habitually associated with conscious activity."7 Indeed, whenever large amounts of specified or functional information are present in an artifact or entity whose causal story is known, invariably creative intelligence -- intelligent design -- played a role in the origin of that entity. Thus, when we encounter a large discontinuous increase in the functional information content of the biosphere as we do in the Cambrian explosion, we may infer -- based on our knowledge of established cause-effect relationships -- that a purposive intelligence operated in the history of life to produce the functional information necessary to generate those forms of animal life.
Instead of exemplifying a fallacious form of argument in which design is inferred solely from a negative premise, the argument for intelligent design formulated in Darwin's Doubt takes the following form:
Premise One: Despite a thorough search and evaluation, no materialistic causes or evolutionary mechanisms have demonstrated the power to produce large amounts of specified or functional information (or integrated circuitry).
Premise Two: Intelligent causes have demonstrated the power to produce large amounts of specified/functional information (and integrated circuitry).
Conclusion: Intelligent design constitutes the best, most causally adequate, explanation for the specified/functional information (and circuitry) that was necessary to produce the Cambrian animals.
The second affirmative premise in this argument makes clear that the design argument in Darwin's Doubt does not constitute an argument from ignorance, nor is it a "purely negative" argument. Indeed, in addition to showing that various materialistic causes lack demonstrated causal adequacy, my argument for intelligent design also affirms the demonstrated causal adequacy of an alternative cause, namely, intelligence. My argument does not omit a premise providing positive evidence or reasons for preferring an alternative non-materialistic cause or proposition.
In fact, the argument for intelligent design developed in Darwin's Doubt constitutes an "inference to the best explanation" based upon our best available knowledge.8 As I note in Chapter 17 of the book, to establish an explanation as best, a historical scientist must cite positive evidence for the causal adequacy of a proposed cause. Unlike an argument from ignorance, an inference to the best explanation does not assert the adequacy of one causal explanation merely on the basis of the inadequacy of some other causal explanation. Instead, it asserts the superior explanatory power of a proposed cause based upon its established -- its known -- causal adequacy, and based upon a lack of demonstrated efficacy, despite a thorough search, of any other adequate cause. The inference to design, therefore, depends on present knowledge of the causal powers of various materialistic entities and processes (inadequate) and intelligent agents (adequate).
Formulated this way, the argument to design from biological information also exemplifies the standard uniformitarian canons of method employed within the historical sciences. The uniformitarian method affirms that "the present is the key to the past."9 In particular, the principle specifies that our knowledge of present cause-effect relationships should govern how we assess the plausibility of inferences we make about the causes of events in the remote past. Determining which explanation, among a set of competing alternatives, constitutes the best depends on knowledge of the causal powers of the possible explanatory entities, knowledge that we acquire through our repeated observation and experience of the cause-and-effect patterns of the world.10 Such knowledge, not ignorance, undergirds my inference to intelligent design from the features of the Cambrian animals. It no more constitutes an argument from ignorance than any other well-grounded inference in geology, archeology or paleontology -- where present knowledge of cause-effect relationships guides the inferences that scientists make about events in the past.
Marshall treats my argument as a "god-of-the-gaps" argument not because it actually has the form of a logically fallacious "argument from ignorance," but because he tacitly presupposes that materialistic causes will ultimately suffice to explain all events in the history of life and that only such explanations count as scientific explanations. Yet we know from our uniform and repeated experience that some types of phenomena -- in particular, information-rich sequences and systems -- do not arise from mindless, materialistic processes. For just this reason, no rational person would, for example, insist that the inscriptions on the Rosetta Stone in the British museum must have been produced by purely materialistic causes such as wind and erosion.
Yet Marshall and many other evolutionary biologists maintain an a priori commitment to purely materialistic explanation for all events in the history of life, even events such as the Cambrian explosion that necessarily involve the generation of massive amounts of new functional information. By privileging prior commitments to a purely materialistic account of evolutionary history over our present knowledge of cause and effect -- in particular, our knowledge that intelligent agents, and only intelligent agents, produce information-rich systems and structures -- Marshall and others disregard the methodological imperatives of the uniformitarian method, privileging what we don't observe (about what happened in the evolutionary past) over what we do observe (the causal powers of various entities and processes). Thus, ironically, Marshall does precisely what he thinks he sees me doing: he allows his own prior commitment to a belief system -- evolutionary materialism -- to trump objective analysis of the observational evidence.
In my next post, I will conclude my response to Marshall with a postscript on two other substantive, but minor, criticisms of Darwin's Doubt.
(1) Charles R. Marshall, "When Prior Belief Trumps Scholarship," Science 341 (September 20, 2013): 1344.
(2) See Stephen C. Meyer, "To Build New Animals, No New Genetic Information Needed? More in Reply in Charles Marshall," at http://www.evolutionnews.org/2013/10/to_build_new_an077541.html and Stephen C. Meyer, "When Theory Trumps Observation: Responding to Charles Marshall's Review of Darwin's Doubt," at http://www.evolutionnews.org/2013/10/when_theory_tru077391.html.
(3) Marshall claims Darwin's Doubt presents "a (sophisticated) 'god of the gaps' approach." Charles R. Marshall, "When Prior Belief Trumps Scholarship," Science 341 (September 20, 2013): 1344.
(4) I explain this point in more detail in my previous book, Signature in the Cell, stating:
The theory of intelligent design does not claim to detect a supernatural intelligence possessing unlimited powers. Though the designing agent responsible for life may well have been an omnipotent deity, the theory of intelligent design does not claim to be able to determine that. Because the inference to design depends upon our uniform experience of cause and effect in this world, the theory cannot determine whether or not the designing intelligence putatively responsible for life has powers beyond those on display in our experience. Nor can the theory of intelligent design determine whether the intelligent agent responsible for information life acted from the natural or the "supernatural" realm. Instead, the theory of intelligent design merely claims to detect the action of some intelligent cause (with power, at least, equivalent to those we know from experience) and affirms this because we know from experience that only conscious, intelligent agents produce large amounts of specified information. The theory of intelligent design does not claim to be able to determine the identity or any other attributes of that intelligence, even if philosophical deliberation or additional evidence from other disciplines may provide reasons to consider, for example, a specifically theistic design hypothesis. (pp. 428-429)
(5) In this regard, for example, see: W. Elsberry and J. Wilkins, "The Advantages of Theft over Honest Toil: The Design Inference and Arguing from Ignorance," Biology and Philosophy, 709-722; Robert T Pennock, Tower of Babel: The Evidence Against the New Creationism, 171-172; Edward O. Wilson, "Intelligent Evolution: The Consequences of Charles Darwin's 'One Long Argument'," Harvard Magazine, 29-33; Eugenie Scott and Glenn Branch, "'Intelligent Design' Not Accepted by Most Scientists," School Board News, Aug. 13, 2002 (http://www.ncseweb.org/resources/articles/996_intelligent_design_not_accep_9_10_2002.asp).
(6) Darwin's Doubt, p. 360, citing Henry Quastler, The Emergence of Biological Organization, p. 16. Emphasis added.
(7) Henry Quastler, The Emergence of Biological Organization, 16.
(8) Peter Lipton, Inference to the Best Explanation, 32-88.
(9) This principle is based upon the arguments of Charles Lyell, Principles of Geology, 75-91.
(10) Peter Lipton, Inference to the Best Explanation, 32-88.; Stephen C. Meyer, "The Scientific Status of Intelligent Design: The Methodological Equivalence of Naturalistic and Non-Naturalistic Origins Theories," in Science and Evidence for Design in the Universe, The Proceedings of the Wethersfield Institute, 151-212; Stephen C. Meyer, "The Demarcation of Science and Religion," in Gary B. Ferngren, ed., The History of Science and Religion in the Western Tradition: An Encyclopedia, 17-23; Elliott Sober, The Philosophy of Biology; Stephen C. Meyer, Of Clues and Causes: A Methodological Interpretation of Origin of Life Studies, Ph.D. dissertation, 77-140.