It appears that the first usage of this term traces to the Christian philosopher Paul de Vries. He used the term orally at a conference in 1983. A few years later it appeared in print in the paper “Naturalism in the Natural Sciences,” Christian Scholar’s Review 15 (1986), 388-96. For de Vries, methodological naturalism says nothing about the existence of God, contrasted with metaphysical naturalism, which actively denies God’s existence. This bit of sleuthing is the work of Ron Numbers.