Teaching Intelligent Design: What Happened When?

A Response to Eugenie Scott

William A. Dembski

Design theorists argue that intelligent design constitutes a valid scientific research program aimed at understanding the effects of intelligence in the natural world. There is currently considerable debate whether this program is indeed valid, and in particular whether concepts like specified complexity or irreducible complexity are coherently defined and can usefully be applied to actual systems in nature.

In her last post to META (METAVIEWS 008, 02.12.01) Eugenie Scott seems willing to allow that intelligent design might some day and in some limited sense achieve scientific legitimacy. In that case, there could be no principled objection to teaching it within science curricula, and particularly whenever the origin and history of life comes up in grades K-12. Yet even without principled objections to the teaching of intelligent design, there could be practical objections, and it's these that Scott focuses on in her last post to META.

To affirm the legitimacy of intelligent design as a proper subject for study within a science curriculum raises two practical questions: (1) How is intelligent design to be taught? and (2) How will the teaching of intelligent design affect the teaching of other scientific subjects, notably biological evolution. One of the worries about intelligent design is that it will jettison much that is accepted in science, and that an "ID-based curriculum" will look very different from current science curricula. Although intelligent design has radical implications for science, I submit that it does not have nearly as radical implications for science education.

First off, intelligent design is not a form of anti-evolutionism. Intelligent design does not, as Eugenie Scott falsely asserts, claim that living things came together suddenly in their present form through the efforts of a supernatural creator. Intelligent design is not and never will be a doctrine of creation. A doctrine of creation presupposes not only a designer that in some manner is responsible for organizing the structure of the universe and its various parts, but also a creator who is the source of being of the universe. A doctrine of creation thus invariably entails metaphysical and theological claims about a creator and the creation. Intelligent design, on the other hand, merely concerns itself with features of natural objects that reliably signal the action of an intelligence, whatever that intelligence might be.

More significantly for the educational curriculum, however, is that intelligent design has no stake in living things coming together suddenly in their present form. To be sure, intelligent design leaves that as a possibility. But intelligent design is also fully compatible with large-scale evolution over the course of natural history, all the way up to what biologists refer to as "common descent" (i.e., the full genealogical interconnectedness of all organisms). If our best science tells us that living things came together gradually over a long evolutionary history and that all living things are related by common descent, then so be it. Intelligent design can live with this result and indeed live with it cheerfully.

But -- and this is the crucial 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. What's more, in that case the justification for common descent cannot be that it follows as a logical deduction from Darwinism.

Darwinism is not identical with evolution understood merely as common descent. Darwinism comprises a historical claim (common descent) and a naturalistic mechanism (natural selection operating on random variations), with the latter being used to justify the former. According to intelligent design, the Darwinian mechanism cannot bear the weight of common descent. Intelligent design therefore throws common descent itself into question but at the same time leaves open as a very live possibility that common descent is the case, albeit for reasons other than the Darwinian mechanism.

What, then, are teachers who are persuaded of intelligent design to teach their students? Certainly they should teach Darwinian theory and the evidence that supports it. At the same time, however, they should candidly report problems with the theory, notably that its mechanism of transformation cannot account for the complex specified structures we observe in biology. But that still leaves Eugenie Scott's question, "What happened when?" There is a lot of persuasive evidence for common descent that does not invoke the Darwinian mechanism, notably from biogeography and molecular sequence comparisons involving DNA and proteins. At the same time, discontinuities in the fossil record (preeminently in the Cambrian explosion) are more difficult to square with common descent.

To establish evolutionary interrelatedness invariably requires exhibiting similarities between organisms. Within Darwinism, there's only one way to connect such similarities, and that's through descent with modification driven by the Darwinian mechanism. But within a design-theoretic framework, this possibility, though not precluded, is also not the only game in town. It's possible for descent with modification instead to be driven by telic processes inherent in nature (and thus by a form of design). Alternatively, it's possible that the similarities are not due to descent at all but result from a similarity of conception, just as designed objects like your TV, radio, and computer share common components because designers frequently recycle ideas and parts. Teasing apart the effects of intelligent and natural causation is one of the key questions confronting a design-theoretic research program. Unlike Darwinism, therefore, intelligent design has no immediate and easy answer to the question of common descent.

Darwinists necessarily see this as a bad thing and as a regression to ignorance. From the design theorists' perspective, however, frank admissions of ignorance are much to be preferred to overconfident claims to knowledge that in the end cannot be adequately justified. Despite advertisements to the contrary, science is not a juggernaut that relentlessly pushes back the frontiers of knowledge. Rather, science is an interconnected web of theoretical and factual claims about the world that are constantly being revised and for which changes in one portion of the web can induce radical changes in another. In particular, science regularly confronts the problem of having to retract claims that it once confidently asserted.

Consider the following example from geology. In the nineteenth century the geosynclinal theory was proposed to account for how mountain ranges originate. This theory hypothesized that large trough-like depressions, known as geosynclines filled with sediment, gradually became unstable, and then when crushed and heated by the earth elevated to form mountain ranges. To the question "What happened when?" geologists as late as 1960 confidently asserted that the geosynclinal theory provided the answer. Thus in the 1960 edition of Clark and Stearn's _Geological Evolution of North America_, the status of the geosynclinal theory was compared favorably with Darwin's theory of natural selection:

"The geosynclinal theory is one of the great unifying principles in geology. In many ways its role in geology is similar to that of the theory of evolution, which serves to integrate the many branches of the biological sciences.... Just as the doctrine of evolution is universally accepted among biologists, so also the geosynclinal origin of the major mountain systems is an established principle in geology." (p. 43)

Whatever became of the geosynclinal theory? Within ten years following this statement the theory of plate tectonics, which explained mountain formation through continental drift and sea-floor spreading, had decisively replaced the geosynclinal theory. The history of science is filled with such turnabouts in which confident claims to knowledge suddenly vanish from the scientific literature. Often they are replaced with more accurate claims. At times no suitable replacement can be found.

But that still leaves the question, What does an ID-based curriculum teach actually happened in the course of biological evolution? As I already indicated, an ID-based curriculum will teach Darwinian theory, both the evidence that supports it as well as the countervailing evidence (and there's plenty of countervailing evidence -- see Jonathan Wells's recent book Icons of Evolution). Moreover, such a curriculum will also teach progress to date on the research problems specific to a design-theoretic research program (see Appendix below).

In particular, as regards the shape of natural history, it will teach what at the time is the best scientific account of the pattern of evolution consistent with biological complexity not being a free lunch. What I mean here is that evolutionary relationships cannot be drawn simply because some naturalistic mechanism is posited as capable of generating biological complexity. Intelligent design argues that naturalistic mechanisms, notably the Darwinian mechanism, are in principle incapable of generating complex specified biological systems. Consequently, whenever evolution exhibits a net increase in such biological complexity, that net increase must be sought in factors other than non-telic naturalistic mechanisms.

Darwinism takes a top-down approach to evolution -- Darwinian theory posits a great tree of life that connects all organisms by descent to a last common ancestor and accounts for that tree in terms of the Darwinian mechanism of natural selection and random variation. Once Darwinian theory is presupposed, reconstructing natural history becomes a matter fitting the data of nature to Darwin's great tree of life. Some data are consistent with that tree, other data are not. In place of a top-down approach that requires in advance that all organisms be evolutionarily interconnected, intelligent design proposes a bottom-up approach in which evolution is confirmed within increasingly wider envelopes of variability. Whether an envelope can be expanded to include all living forms (thus implying common descent) is for now an open question facing intelligent design.

When it comes to integrating intelligent design with current science curricula, it's important to understand that intelligent design departs from these curricula principally over the origin of biological complexity. True, intelligent design also takes up design in cosmology. But arguing for design at the level of cosmology does not contradict any of the theories currently held by cosmologists (for instance, Big Bang and inflationary cosmologies can be interpreted as consistent with intelligent design). Arguing for design in biology, on the other hand, does squarely challenge Darwinian theory and more generally all purely naturalistic accounts of biological complexity. But that's about all intelligent design challenges. Thus one can be quite conservative in adapting intelligent design to a science curriculum. There's no need, for instance, to alter our understanding of cosmology or geology regarding the formation of the universe, galaxies, our solar system, or the earth. Nor for that matter is there any need to challenge the standard chronologies scientists have assigned to these events (e.g., 12 or so billion years for the age of the universe and 4.5 billion years for the age of the earth).

The clarion call of the intelligent design movement is to "teach the controversy." There is a very real controversy centering on how properly to account for biological complexity (cf. the ongoing events in Kansas), and it is a scientific controversy. Eugenie Scott regularly pretends that it will only confuse students to teach intelligent design in public school science curricula. In fact, what confuses students is to be taught only the party line while being aware that the party line is under serious critical scrutiny. As director of the National Center for Science Education, an organization whose avowed aim is to defend the teaching of Darwinian evolution against all interlopers, Eugenie Scott can do no better than play to her constituents and claim that intelligent design is the latest flash in the pan of anti-Darwinian sentiment. But this stonewalling can only continue so long, especially in the age of the Internet, when the safe control of ideas can no longer be guaranteed.

Appendix: Design-Theoretic Research Problems

  1. Detectability Problem -- Is an object designed? An affirmative answer to this question is needed before we can answer the remaining questions. The whole point of specified and irreducible complexity is to make an affirmative answer possible.
  2. Functionality Problem -- What is the designed object's function? This problem is separate from the detectability problem. For instance, archeologists have discovered tools which they recognize as tools but don't understand what their function is.
  3. Transmission Problem -- What is the causal history of a designed object? Just as with Darwinism, intelligent design seeks historical narratives (though not the just-so stories of Darwinists).
  4. Construction Problem -- How was the designed object constructed? Given enough information about the causal history of an object, this question may admit an answer.
  5. Reverse-Engineering Problem -- In the absence of a reasonably detailed causal history, how could the object have come about?
  6. Constraints Problem -- What are the constraints within which the designed object functions optimally?
  7. Perturbation Problem -- How has the original design been modified and what factors have modified it? This requires an account of both the natural and the intelligent causes that have modified the object over its causal history.
  8. Variability Problem -- What degree of perturbation allows continued functioning? Alternatively, what is the range of variability within which the designed object functions and outside of which it breaks down?
  9. Restoration Problem -- Once perturbed, how can the original design be recovered? Art restorers, textual critics, and archeologists know all about this.
  10. Optimality Problem -- In what sense is the designed object optimal?
  11. Separation of Causes Problem -- How does one tease apart the effects of intelligent causes from natural causes, both of which could have affected the object in question? For instance, a rusted old Cadillac exhibits the effects of both design and weathering?
  12. Ethical Problem -- Is the design morally right?
  13. Aesthetics Problem -- Is the design beautiful?
  14. Intentionality Problem -- What was the intention of the designer in producing a given designed object?
  15. Identity Problem -- Who is the designer?

Note that the last four questions are not properly questions of science, but they arise very quickly once design is back on the table for serious discussion. As for the other questions, they are strictly scientific (indeed, many special sciences, like archeology or SETI, already raise them). Now it's true that some of these questions have analogues within a Darwinian naturalistic framework (e.g., the functionality problem). But others clearly do not. For instance, in the separation of causes problem (i.e., teasing apart the effects of intelligent causes from natural causes) has no analogue within a naturalistic framework.