Modality, probability, and rationality: A critical examination of Alvin Plantinga's philosophy

This dissertation presents a critical analysis of many of the central doctrines in the philosophy of Alvin Plantinga, particularly his religious epistemology. I identify a theme I see running through his work: His defense of what I call "The Plantinga Thesis": PT: There is no plausible epistemological theory that rules out theistic belief as a category of epistemically appropriate belief. I examine three of Plantinga's primary strategies in arguing for PT: His work on the ontological argument, the problem of evil, and "Reformed epistemology"--the claim that theistic belief can be justified without propositional evidence.;Central to my criticism is my identification of a distinction that Plantinga fails to appreciate--that between pure (or metaphysical) modality and epistemic modality. This failure affects the success of all of the examined projects. Plantinga makes logical moves that are legitimate only if the former sense is in focus, while the premises from which such moves are made are justified only if understood in the latter sense. Consequently, Plantinga often asserts conclusions that his argumentation does not support.;My verdict on Plantinga's defense of PT is a mixed one, however. The flaw I identify affects his work on the ontological argument and Reformed epistemology to a greater extent than it does his work on the problem of evil. This is, in part, because the first two are attempts to argue for the justification of theistic belief, while the third is an attempt to block an objection to theistic belief.;I conclude that Plantinga's defense of PT is not nearly as strong as he thinks it is--that, in fact, it fails completely in some important places. Nonetheless, I do demonstrate that his thinking and writing hold an important place in contemporary philosophy. Whatever its level of success, his work is always provocative and often engenders protracted and productive debate on related issues. Accordingly, I conclude with a litany of issues and subjects for research suggested by Plantinga's work.