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What is Wrong with Sober's Attack on ID? (Part II): Comparing ID and Darwinism while Ignoring Darwinism's Epicycles

In Part I, I explained how Elliott Sober's recent attack upon ID in his article entitled "What is Wrong With Intelligent Design?" gave an inaccurate history of intelligent design. This second part will discuss how Sober's reasoning necessarily implies that ID is testable, except for the fact that he applies a double standard and ignores the ad hoc explanations so commonly used by Darwinists to square their theory with the data.

Testing by Comparing Predictions of Theories
Sober concedes that "many formulations of ID are falsifiable" and meet Karl Popper's famous criteria that a scientific theory must be falsifiable. However, Sober critiques Popper's usage of falsifiability as a hallmark property of science because he claims it does not always entail robust testability relative to other explanations. Sober prefers a definition of testability where testing is conducted by comparing a theory to other competing theories. He writes: "To develop an account of testability, we must begin by recognizing that testing is typically a comparative enterprise."

Thus, in Sober's view, ID must make predictions with respect to neo-Darwinism in order for ID to be testable: "If ID is to be tested, it must be tested against one or more competing hypotheses." His method might be called "relative testability," and it has clear implications for the scientific status of ID: Since Sober measures ID's testability by comparing it to neo-Darwinism, the implication is that Sober should measure the comparative testability of neo-Darwinism by trying to test it against ID. The unavoidable conclusion is that under Sober's methodology, ID and neo-Darwinism must have equal, relative testability with respect to one-another. Obviously Sober believes that neo-Darwinian evolution is a scientific theory, so doesn't that mean ID must also qualify as a scientific theory? Yet Sober implies ID is not a scientific theory, revealing a possible double-standard.

In the end, Sober doesn't even use this "relative testability" methodology. Instead, he ignores the wholly standard formulation of intelligent design in order to claim that it's untestable. This will be explained more in Part III of this series.

Sober's Auxiliary Propositions
Sober writes: "It is crucial to the scientific enterprise that auxiliary propositions not simply be invented. By inventing assumptions, we can equip a theory with favorable auxiliary propositions that allow it to fit the data." Auxiliary assumptions, when misused, are like the epicycles used to defend the long-discarded geocentric model of the solar system: they are post-hoc explanations used to square a theory with contrary data. I agree with Sober's statement here, which makes it all the more curious that Sober fails to recognize how often Darwinists have made auxiliary propositions to square their theory with the data:

  • (1) Convergent evolution, horizontal gene transfer, lack of data (and any number of mathematical contortions) suddenly come into vogue to explain why organismal similarities exist between species where common descent would predict they shouldn't exist,

  • (2) Punctuated equilibrium abruptly comes into vogue to attempt to explain the widespread lack of transitional forms in the fossil record,

  • (3) Co-option and exaptation are now extremely popular to replace natural selection and adaptation in a pitiful attempt to explain how irreducibly complex features evolve.

    Evolutionists will respond that they aren't "inventing assumptions," but have a rational basis for announcing their new auxiliary propositions (Sober requires that auxiliary propositions must be "independently justified"). Whether these assumptions are the result of a rational analysis or rationalization can be debated. But it's curious that Sober ignores his own side's fondness of announcing the popularity of new auxiliary propositions to save neo-Darwinism from the latest challenges of the data.

    Incredibly, Sober repeats argument (3) above in his article, providing an ad hoc explanation for why irreducibly complex systems aren't impossible under Darwinian evolution, but merely have a "low probability." According to Sober, an event which has a low probability under evolution but has apparently happened numerous times in the history of life does not count against neo-Darwinian evolution. It seems like Sober is putting neo-Darwinism in an unfalsifiable position by inventing auxiliary propositions, but Sober does not seem to recognize any of this in his paper.