Methodological naturalism without metaphysical naturalism

A student of mine pointed out to me this recent New York Times article. It's about Marcus Ross, who recently received his Ph.D. in geology, writing a perfectly normal geology dissertation about what happened 10-15 million years ago -- except this guy is actually a young earth creationist, that is, he believes the Earth is no more than 10,000 years old, based on a literal interpretation of Genesis. Ross says he works within one "paradigm" when writing his dissertation and working within the geological community, but he does not accept this paradigm for all contexts.

A number of interesting things could be said about this (and many are in the NYT article). I wanted to highlight one of the more philosophical aspects of this case. In the context of the debate over Intelligent Design, the anti-evolutionists often say 'Darwinism is a religious belief (perhaps atheism in disguise).' Many pro-evolutionists respond by drawing a distinction between methodological naturalism and metaphysical naturalism, where only the second is anything close to a religious belief. Here's a rough characterization:

(Methodological Naturalism) Scientific explanations cannot appeal to supernatural causes.

(Metaphysical Naturalism) There are no supernatural causes.

The pro-evolutionists say that science only requires methodological naturalism, not the metaphysical naturalism that is pretty close to atheism. So one could be a methodological naturalist, but need not be a metaphysical naturalist (though presumably not vice versa). One natural response the anti-evolutionist could make is that this distinction is contrived, artificial, or otherwise objectionable.

Well, now Marcus Ross is a striking real-life example of someone who is a methodological naturalist without being a metaphysical naturalist. You might think this would make the pro-evolutionists happy -- but as the NYT article makes clear, not all of them are. There are different reasons for this dissatisfaction (e.g., the young earth creationists can now claim this bona fide geologist is on their side). But one thing that perhaps drives the dissatisfaction is that, to quote the student who showed me this article, this person's beliefs seem "crazy". His mental life seems fragmented or segregated in the extreme.

Somewhat ironically, this case appears to serve as a particularly vivid example in favor of the anti-evolutionists' claim that the distinction between methodological and metaphysical naturalism is bogus. On the other hand, in defense of the distinction, perhaps it is not this geologist's metaphysical supernaturalism that makes his stance seem odd, but rather his further beliefs about the particular, specific nature of the divine causes, viz., creating the Earth 10,000 years ago or so.