Alvin Plantinga's externalist analysis of epistemic warrant centres on the proper function of the relevant belief-forming mechanism, where proper function is fixed relative to the design plan of the organism in question. He has set this analysis against reliabilism, the other leading externalist contender for the analysis of warrant. Though Plantinga's discussion advances the field of epistemology in a number of important ways, his treatment of warrant is limited by his assumption of creationism in his understanding of design and function. Further, analyses of epistemic warrant focusing on function over reliability either fail at handling problem cases reliabilism can handle, or fail to improve on problem cases for reliabilism. Thus no proper functionalist analysis like Plantinga's can supersede a well-constructed reliabilist analysis.