Naturalism Under the Microscope - Evolution News & Views

Evolution News and Views (ENV) provides original reporting and analysis about the debate over intelligent design and evolution, including breaking news about scientific research.

Evolution News and Views
Science NEWS

Naturalism Under the Microscope

6629875959_4fea884c9e_m.jpgTwo recent lectures in Chicago highlighted the centrality of "naturalism" to the ID debate. The first, on Wednesday, April 11, by University of Minnesota philosopher of biology Alan Love, focused on methodological naturalism (MN), and asked whether -- as MN's advocates argue -- the principle is necessary for scientific practice.

The second lecture, on Friday, April 13, was given by University of Wisconsin philosopher of biology Elliott Sober. He asked if the "unguided" mutations posited by current evolutionary theory entail that God was not involved in the history of life on Earth. What follows is part 1 of a report on the main lines of argument in both lectures, concluding with some commentary in response. I'll cover Alan Love's talk today, and hope to write on Elliott Sober's, in part 2, subsequently.

Alan Love, Wheaton College, April 11: "Methodological Naturalism Reconceived (or Elided)?"

AlanLoveImage.gifMethodological naturalism (MN) -- the philosophical doctrine that scientific explanations must refer only to natural causes -- is the central and most controversial concept in all discussions of evolution, creationism, and intelligent design, Love said. MN must "wear a lot of hats," however. The principle has functioned as (1) an epistemological ground rule about scientific explanation, (2) an historical account concerning the emergence of professional science, (3) a fence demarcating science from theology and philosophy, and (4) a mediating concept facilitating dialogue between science and faith.

Yet MN, Love continued, represents "a paradox." While claimed by its advocates to be essential to science, MN is rarely mentioned by scientists themselves in their primary publications, or in philosophical analyses of particular sciences. "If you don't mention MN" as a practicing scientist, Love said, "no one notices." Furthermore, if one inspects leading philosophy of science journals, such as the British Journal for the Philosophy of Science, or Philosophy of Science, one finds only a handful of references to MN, almost always in the context of the ID debate.

A "quick resolution" of the paradox, Love said, would hold either that MN is not essential to science (hence, MN doesn't show up where one might expect to see it), or, more plausibly, that MN is a tacit but nonetheless widely accepted rule, so ubiquitous that -- except for unusual contexts, such as the ID debate -- it doesn't need mentioning out loud.

But these quick resolutions don't work, said Love. Something akin to MN does appear to be central to modern science (see below), so we can't just wave MN off as irrelevant. On the other hand, it would be exceedingly odd if MN, claimed to be a central principle of scientific method, could function wholly out of sight, as a "subterranean" rule. How does an entirely tacit rule differ from no rule at all?

Getting Past the MN Paradox

The resolution of the paradox, Love argued, begins with realizing that MN is not a "global" ground rule demarcating science from other disciplines or practices. Such claims "are overstated," as global rules for what counts as science do not in fact exist. Scientists rarely mention MN in their publications or discussions, because their concerns are actually much more "local," turning on matters specific to, or arising within, particular sciences. Taking his lead from University of Pittsburgh philosopher of science John Norton's 2003 paper, "A Material Theory of Induction," Love suggested that trying for universally valid accounts of scientific inference, and rules like MN to demarcate such inferences, are enterprises doomed to frustration. (See also Norton's 2010 development of his critique of universal theories of induction.) Rather, material inferences in any science "are licensed by their empirical content," and this is a matter of degree, because content varies, and is not an all-or-nothing proposition.

Thus, Love said, if one is looking for something playing the role of MN in any particular science, one should focus on what he called "material inferential capacities," abbreviated as MICs. MICs, rather than general formulae about induction (e.g., the so-called "scientific method"), are what scientists learn in their training, actually employ in explanation, and recognize as grounding legitimate inferences. Viewing scientific practice "close up," rather than from the abstract distance of MN "at 30,000 feet," reveals the role of discipline-specific MICs, where scientists "learn by doing" in "particular communities." These are the tools (and rules) that scientists actually recognize as relevant, and thus MICs are highly localized, not global, in form and content.

While this "local MIC" perspective surrenders any global rule of MN, Love said, it nevertheless "offers no solace to ID proponents." The latter, he said, fail to "recognize the relevant MICs of evolutionary biology," and therefore their criticisms of evolutionary theory are seen by most biologists as wrong or missing the point. The "increased precision" afforded by the MIC perspective "makes sense of scientific practice" in a way that MN does not, and moreover "circumvents worries that global MN pre-stipulates" the shape of reality.

Paul's Response: The Whole Point of MN Is to Be an All-Purpose Defeater (Global Rule of Science)

Material inferential capacities (MICs) make perfect sense to me, as descriptions of the actual content of any particular (or special) science. Learn a science, and one learns a set of specific MICs -- not "the scientific method," or the rules of science, or some other collection of abstract formulae governing proper induction.

But what MICs cannot do, in principle, is the exclusionary work of methodological naturalism (MN). That is precisely what the defenders of MN, however, intend for the principle to do: keep the bad guys, and their ideas, out of science, come what may. MN is not a neutral canon of method, which makes no claims about the true state of the world, but allows the evidence to speak for, or against, such possibilities as intelligent design. Rather, MN -- if it is going to play the role of the "fence" or "ground rule" its advocates (e.g., Pennock 2011) desire -- must make global claims about the shape of reality. This is the way the universe is; therefore, science must follow.

And MN does just that. Here's how Pennock (2011, 184) expresses the principle:

MN holds that as a principle of research we should regard the universe as a structured place that is ordered by uniform natural processes, and that scientists may not appeal to miracles or other supernatural interventions that break this presumed order.

Now, Pennock himself is quite certain that the universe indeed exists as MN describes it -- "a structured place ordered by uniform natural processes" -- so science can hardly go wrong by following MN. But, for any curious person who wonders if the universe should have a chance to speak for itself, before principles like MN exclude empirical possibilities a priori, MN can only block open inquiry. What if "uniform natural processes" did not actually cause (for instance) the origin of life? Could we discover that to be the case, if we assume MN?

Because Love's MIC perspective surrenders the global scope of MN, which is necessary to MN's role as a philosophical fence, it will allow all sorts of questions and possibilities that MN would automatically exclude. Nothing in the content of any science -- no actual MIC -- tells the investigator that the content is complete or sufficient, or what that science may stumble upon tomorrow. So, if someone asked, "Hey, in the light of these new data, may I try the idea of intelligent design?" no MIC could rule against that investigator. MICs are always based on what a science has done in its past, not what the science may try in the future.

Pennock's formulation of MN, by contrast, defines the shape of empirical reality: uniform natural processes. As such, his version of MN really does rule out ID, which of course explains why the ACLU used it at the Dover trial. Love doesn't want to legislate reality by global stipulations, but in surrendering that goal, he gives up the very reason Pennock and others push MN. In opting for the descriptive accuracy of MICs, Love yields the proscriptive role of MN that Pennock and others want.


Most defenders of MN say the principle is modest and neutral, shying away from the universal assertions of philosophical naturalism (PN). But is that true? A few years ago (2006, p. 344), Marcus Ross and I wrote the following:

Ask oneself a simple question. Suppose life actually were designed by a nonhuman intelligence -- would MN allow us to discover that? If the answer is no, then MN hinders scientific discovery and dictates the shape of reality as thoroughly as PN. If the answer is yes, then MN is superfluous and says nothing more than science should be empirical and testable.

MN is a rule without a decent justification. Love knows that, I think, but his MIC perspective, while illuminating, cannot take the place of MN. And thank goodness for that.


Pennock, Robert. 2011. Can't philosophers tell the difference between science and religion?: Demarcation revisited. Synthese 178:177-206

Ross, Marcus and Nelson, Paul. 2006. A Taxonomy of Teleology. In W. Dembski, ed., Darwin's Nemesis (Downers Grove, IL: InterVarsity Press)