Methodological Naturalists Need Not Commit to Metaphysical Naturalism

In their paper “Should Methodological Naturalists Commit to Metaphysical Naturalism?” Zargar et al. try to show that the correct answer to the question that the title of their paper poses is positive. They argue that methodological naturalism has a metaphysical presupposition, namely causal closure, and an epistemological consequence, namely evidentialism. Causal closure and evidentialism imply metaphysical naturalism. Thus, they conclude, one who believes in methodological naturalism should also endorse causal closure, evidentialism, and metaphysical naturalism as a result. In this paper, I criticize their argument and argue that it is deficient in (at least) two different ways. First, what they consider to be methodological naturalism is in fact a strawman: that is another – more radical – thesis that may be called methodological anti-supernaturalism. Second, and most importantly, even methodological anti-supernaturalism does not in essence need causal closure for its justification. Then, methodological naturalists are not required to adhere to causal closure or metaphysical naturalism.