Philosophy Is Essential to the Intelligent Design Debate

Predictably, the attempts by advocates of intelligent design (ID) to persuade Ohio’s state school board to over-rule the state’s science advisory board and insert ID ideas into the Ohio science standards have sparked a controversy. Inevitably, the usual combatants in the science–religion wars have rushed to their respective barricades. ¹  

ID advocates argue that scientists are somehow conspiring to suppress ID ideas. They accuse scientists of practicing censorship by arbitrarily excluding ID ideas from journals and science textbooks, thus not giving the ideas a fair chance to gain adherents. To overcome this perceived injustice, ID advocates have appealed directly to political power structures such as school boards and legislative bodies to mandate what should be included in science.

Although such bodies may have the authority to tilt science curricula toward religion, history has not looked kindly on such efforts. The attempts in Louisiana and Arkansas in the 1980s to mandate the teaching of creation science, and the more recent attempt in Kansas to eliminate the teaching of evolution, were debacles for their proponents. They invited dismal comparisons with the Roman Catholic Church’s attempt in 1616 to ban Copernican theory or the Soviet Central Committee’s attempt in 1949 to dismiss Mendeleevian genetics as pseudoscience. One wonders why this dubious strategy is still being pursued.

What is interesting about this battle is that both pro-ID and anti-ID sides casually toss around terms like the “verifiability,” “testability,” and “falsifiability” of theories, as if the meanings of the words were self-evident. Both sides display little awareness that historians and philosophers of science created and have exhaustively studied the terms in the quest to understand the nature of science. These scholars find that all such concepts fail to satisfactorily explain how science progresses. ^2–6 The problem of how to unambiguously distinguish science from nonscience is an extremely difficult one. ⁶ It even has a venerable name, “the demarcation problem.” This rich scholarly tradition should play an important role in this discussion, and there is no excuse for ignoring it.

For example, ID advocates claim that “empirical science” consists of those disciplines in which the merits of competing theories can be evaluated by running controlled experiments to “test” them. However, ID advocates also claim that “origins science” (like evolution of life or the cosmos) cannot be investigated empirically because the experiment cannot be run again with controlled initial conditions. Hence they propose, as an alternative methodology for evaluating origins science, that all competing hypotheses be applied to see which one gives the best explanation. They further assert that the only sound hypotheses for the evolution of life are natural selection or ID, and that since natural selection fails in certain situations (referred to as “irreducibly complex” systems ⁷ ), then, by the rules of “falsifiability,”³⁴ ID must be the correct theory.

This argument has four flaws. First, although the tools of analysis may be different for so-called origins science and empirical science (consisting mainly of observations for origins science and experiments for empirical science), the ways in which competing theories are evaluated are the same for the two cases. Second, it is never the case that only two explanations exist for any scientific phenomenon. Scientists are creative people. They can generate plausible alternative explanations with little effort. Third, ID theory does not satisfy the criteria to be considered part of science. Fourth, “falsifiability” is not the rule by which scientific theories are evaluated.

Although research in the history and philosophy of science convincingly demonstrates that there are no simple and unambiguous methodological rules for deciding which of two (or more) competing theories are better, ^2,4,5 theories must meet two criteria if they are to be seriously considered at all. The first criterion is that any scientific theory must be naturalistic. No serious scientific theory in modern times has invoked explanations that appeal to inscrutability or the miraculous. As the paleontologist George Gaylord Simpson put it,

The second criterion is that the theory must be predictive. No scientific theory is ever just an explication of the currently inexplicable. It must also postulate some mechanism that can be used to predict new phenomena that could not have been conceived under older theories. If a new theory is used to explain result a in situation A, then that same mechanism must be able to predict result b in situation B, predict c in situation C, and so on. This feature of producing new and interesting areas of exploration attracts adherents to a new theory, enabling it to become a serious competitor to the existing dominant theory. ⁴ It is a theory’s predictive aspect that leads to new and important discoveries. These two criteria comprise necessary (but insufficient) conditions for a theory to be considered a part of science. ID fails to satisfy either criterion, and that alone is reason enough for its exclusion.

ID advocates respond that these are philosophical rules, as if that were a disqualification. But just because a rule is philosophical does not mean that it lacks value. In fact, these particular rules have been key to the tremendous advance of science. While scientists may accept that some problems are unsolved—or cannot be solved until new technology or data become available—they never accept that a scientific problem is inherently insoluble. This belief that only their own ingenuity or effort stands between them and success is what makes them persevere for years and leads to great breakthroughs. But when ID is invoked as an explanation for something, its advocates are essentially stating that the problem is inherently insoluble and the solution is inscrutable. Research in that area would presumably come to a halt.

It is absurd for some scientists to defend Darwinian natural selection by saying that there is no feature of life that cannot be explained by it. No scientific theory has ever explained all the phenomena that fall within its domain. ^2,4,5 Unexplained problems will always arise that resist solution for a long time. In fact, a good theory is one that keeps generating new problems that scientists can work on and that lead to new discoveries and insights. ID advocates will never run out of cases in which Darwinian natural selection has not yet provided an explanation. But the presence of such anomalies has never been sufficient, by itself, to prompt the scientific community to abandon a dominant theory. ^2,4,5

For example, the motion of the perigee of the moon was a well-known unsolved problem for over 60 years after the introduction of Newtonian physics. ² It constituted a serious problem that resisted solution for a longer time than the problems in evolution indicated by ID advocates. Yet no supernatural explanation was invoked. Eventually, the problem was solved, and the result was seen as a triumph for Newtonian theory. Similarly, the stability of the planetary orbits was an unsolved problem for more than 200 years. ⁵  

These two examples successfully illustrate why simple methodological rules like falsifiability do not explain science’s progress. If such a rule were rigorously enforced, then Newtonian physics (and indeed every scientific theory ever proposed) would have been falsified and rejected at birth and we would not have had any science at all. Clearly, scientists make judgments about which theories to keep and which to reject for reasons that are far more complex and subtle than suggested by simple rules like falsifiability.

Scientists consider the merits of competing theories only when science enters a period of crisis—that is, when a dominant theory, despite repeated attempts by its most seasoned practitioners, fails to explain something that should be explainable using existing knowledge, technology, and techniques. ² The biological science community apparently does not perceive that natural selection is in such a state of crisis. But even if natural selection were in crisis, biologists would not accept ID as a worthy rival. Instead, they would look for alternative naturalistic and predictive theories. If the history of science is any guide, biologists will find and agree on an acceptable theory. That is the way science has evolved.

The last philosophical question about ID involves the role of “truth.” ID advocates argue that it is wrong to keep ID ideas out of science by appealing to naturalistic and predictive rules because the goal of science is to seek “the truth.” How, they ask, will we know if ID is the true explanation for a phenomenon if it is not allowed to compete?

But there is no reason to think that “truth” plays a major role in this discussion. ² Science constantly produces new theories and discoveries that are powerful, useful, and enlightening. But does that imply we are approaching “the truth”? Alas, no—although many scientists would like to think so. ^2,9

Given the continuing success of science, this limitation is not an easy idea to grasp, especially for scientists. To better understand it, compare the progress of science with that of biological evolution itself. Organisms evolve; new ones emerge from the old, which results in the impressive array of living systems around us that are, for the most part, wonderfully adapted to their present environments. Does this mean that the process of evolution was directed toward a goal? That the present living forms were preordained in the primeval soup? Of course not. The life forms that exist now just happen to be the ones that arose from a vast number of initial possibilities.

Likewise, scientific theories evolve according to how well they answer, at any given time in history, the immediate questions of interest to scientists. As a result, the present impressive array of theories has developed to satisfactorily answer the questions that interest us now. But that does not mean that science is goal-directed and thus progressing toward the “truth.” The present theories were not predetermined to be discovered, any more than the first amphibians that crawled out of the oceans many years ago had the concept of humans encoded for future emergence. Science works—and works exceedingly well—because of its naturalistic approach, predictive nature, and methods of operation. To be valid, science does not have to be true. ⁹