Abstract

The penultimate chapter of Alvin Plantinga's "Warrant and Proper Function" attacks metaphysical naturalism through an argument which concludes that only a supernaturalistic worldview can accommodate the indispensable concept of proper function. I make the case that this argument, which I dub 'the argument from proper function', suffers from two major flaws. First, it underestimates the naturalist's ability to ground natural proper function ascriptions in the concept of health. Second, it relies upon an overly stringent standard for successful conceptual analysis; ironically, the naturalist can undercut the argument by adopting Plantinga's own recommended model for analysing concepts.