a sound mind, in an environment supportive of proper thought in accord with a design plan successfully aimed at truth. Because there is an epistemically possible model according to which theistic belief is properly basic and designed to form true belief in God, belief in God is probably warranted if theism is true. Plantinga does not argue that this model is true, but only that if it is true, theistic belief is also likely true, because then theistic belief would result from our belief-forming faculties functioning as they were designed. This connection between the truth value of theism and its positive epistemic status suggests to some that the goal of showing theistic belief to be externally warranted requires reasons for supposing that theism is true (Sudduth, 2000). This point is answered by many theistic arguments which purport to provide sufficient propositional and physical evidence to warrant that belief, apart from reformed epistemology. Plantinga's Reformed epistemology According to Reformed epistemology, belief in God can be rational and justified even without arguments or evidence for the existence of God. More specifically, Plantinga argues that belief in God is properly basic, and due to a religious externalist epistemology, he claims belief in God could be justified independently of evidence. His externalist epistemology, called "Proper functionalism", is a form of epistemological reliabilism. Plantinga discusses his view of Reformed epistemology and proper functionalism in a three-volume series. In the first book of the trilogy, Warrant: The Current Debate, Plantinga introduces, analyzes, and criticizes 20th-century developments in analytic epistemology, particularly the works of Roderick Chisholm, Laurence BonJour, William Alston, and Alvin Goldman. Plantinga argues that the theories of what he calls "warrant"—what many others have called justification (Plantinga draws out a difference: justification is a matter of fulfilling one's epistemic duties, whereas warrant is what transforms true belief into knowledge)—put forth by these epistemologists have failed to capture in full what is required for knowledge. In the second book, Warrant and Proper Function, he introduces the notion of warrant as an alternative to justification and discusses topics like self-knowledge, memories, perception, and probability. Plantinga's "proper function" account argues that as a necessary condition of having warrant, one's "belief-forming and belief-maintaining apparatus of powers" are functioning properly—"working the way it ought to work". Plantinga explains his argument for proper function with reference to a "design plan", as well as an environment in which one's cognitive equipment is