Natural law and intelligent design

Matthew Yglesias hits the nail on the head.

Science presupposes, rather than demonstrates, that the supernatural does not play an important role in the unfolding of the universe.

One of the biggest mistakes scientists make is a result of philosophical naivete. From the fact that we seek explanations in terms of natural law operating on material entities (matter and energy), many scientists infer that only material entities exist. As Yglesias points out, excluding the supernatural from scientific explanation is a methodological presupposition of science, not an empirical conclusion of scientific research.

Another way of saying this is that while the metaphysical proposition that only material entities exist is defensible, it is a metaphysical proposition, not an empirical one. As a scientist, I provide explanations for those phenomena I understand in terms of the operation of natural law on material entities. But so long as I wear my scientist's hat, I must remain agnostic about whether there are non-material, supernatural entities and whether satisfactory explanations of them can be provided. Only when I take off that hat and don my philosopher's hat¹ can I express an opinion about the metaphysical question.

¹I may not be a particularly good philosopher, but I do periodically teach a course in philosophy of science, and I've even published a couple of papers in Philosophy of Science.