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Denying the Signature: More on Substance Dualism


Editor's note: Readers of Evolution News likely know the central thesis of Stephen Meyer's bestseller, Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design. Meyer argues that the functional biological information necessary to build the Cambrian animals is best explained by the activity of a designing intelligence, rather than an undirected, materialistic evolutionary process. Most reviews of Darwin's Doubt curiously omitted to address or even to accurately report this central claim. However, a review by philosophers Robert Bishop and Robert O'Connor in Books & Culture was a welcome exception. In this 6-part series, adapted from Debating Darwin's Doubt, edited by ENV's David Klinghoffer, Dr. Meyer responds to their critiques. This is Part 6 of the series. Look here for Parts 1, 2, 3, 4, and 5.

Meyer series.jpgThough I don't need to justify substance dualism as a condition of making design inferences, it doesn't follow that there are not good justifications either for (a) presupposing some form of minimalist pre-theoretic form of dualism or (b) for the philosophical position of substance dualism itself.

In the first place, some form of dualism may well be a properly basic belief, justified by the universal human experience of being aware of ourselves as simple, conscious subjects or "I's" distinct from our physical bodies. Since we have a similar awareness of our mind's causal powers (and their ability to exercise "downward" causation on the physical world as opposed to being a mere epiphenomenon resting inertly atop a neurophysiological substrate) our pre-theoretic awareness of these powers may well implicitly constitute a dualist understanding of mind. Yet, it does not follow from this fact that our pre-theoretic conceptions of mind need explicit philosophical justification. Instead, assuming a (minimally dualistic) conception of mind may well be a properly basic belief.

Indeed, virtually everyone accepts the belief that their minds have causal powers, including powers that material objects and process do not. Moreover, even those few materialist scientists or philosophers who deny this belief in their explicit philosophical or scientific statements betray a commitment to it in many ways as they go about their daily lives. Materialists cannot live consistently with their own denial of the causal powers of their own minds. Instead, their actions betray their belief in those powers.

In addition, virtually no one gives arguments for -- or, more importantly, feels the need to give arguments for -- their belief in the causal powers of their own mind. And almost no one (save for a few ideologically-zealous physicalist philosophers) thinks there are defeaters for this belief. For all these reasons, it seems the common belief that our minds have causal powers, including causal powers that material objects and processes do not, seems to qualify as properly basic.

In any case, there are also good explicit scientific and philosophical arguments justifying substance dualism as a theory of mind-body interaction. See, for example, The Mysterious Matter of Mind, by Arthur Custance, which summarizes the many neurophysiological experiments that led neuro-scientists such as Wilder Penfield and Sir John Eccles to adopt a "dualist interactionist" view of mind and brain.1 See also Angus Menuge's Agents Under Fire for a good philosophical defense of substance dualism.2 Just as there are good philosophical arguments showing that a minimalist pre-theoretic form of dualism does not need justification (i.e., is properly basic), there are also good scientific and philosophical arguments justifying substance dualism as a good theory of mind-body interaction.

Nevertheless, Bishop and O'Connor think that because mind-body dualism requires a philosophical justification, intelligent design does not qualify as a scientific theory, but instead "looks more like philosophy than science." But that doesn't follow for several reasons already discussed: The case for intelligent design does not depend upon substance dualism; a more minimalist pre-theoretic form of dualism doesn't necessarily require any justification (and may be regarded as properly basic); and there are scientific, as well as philosophical, justifications for substance dualism (or the closely related position of dualist interactionism).

In any case, many scientific theories -- Einstein's theory of general relativity, Newton's theory of universal gravitation, and Darwin's theory of evolution, to cite just a few examples -- are, arguably, based upon deeper philosophical premises, presuppositions, and concepts, which either can be, or need to be, justified by philosophical lines of argument. Despite their background in the philosophy of science, Bishop and O'Connor seem to assume the ability to make strict demarcations between science and philosophy in a way that philosophers of science have now almost universally repudiated (for reasons that I explain in both my books). Besides, as I argue in both books, what matters is not how we classify a theory, but whether a theory is true or warranted by the evidence.

One final point is worth making. Though I'm not obligated to justify substance dualism as a theory of the mind, I would certainly concede that offering a robust philosophical and/or scientific justification for such a theory would enhance the philosophical importance of the case I make for intelligent design.

If mind cannot be adequately accounted for by reference to materialistic processes, then any evidence of mind acting in the history of life would pose a more explicit challenge to the philosophy of scientific materialism than I develop in my books. It would provide evidence of an immaterial agency acting in the history of life. If, in addition, there is strong evidence for the activity of a designing agent establishing the finely tuned conditions of the universe present from its beginning, as I believe there is, then the conjunctions of these considerations would provide strong grounds for theistic belief.


(1) Arthur C. Custance, The Mysterious Matter of Mind (second online edition, 2001; originally published by Probe Ministries and Zondervan Publishing, 1980).

(2) Angus Menuge, Agents Under Fire: Materialism and the Rationality of Science (Lanham, MD: Rowman & Littlefield, 2004).