 The formality of definitions like the one cited by Plantinga is likely to conceal underlying disagreements about what counts as a concrete instance of fideism. Indeed, there is little agreement among philosophers about which thinkers can properly be subsumed under this rubric. To offer a straight “history of fideism” would thus require one to take up a particular position with respect to a series of ongoing philosophical disputes. This section thus attempts – somewhat less ambitiously, though perhaps more charitably – to sketch a brief history not of fideism but of “fideism” – i.e., of the term’s (contested) usage within the philosophical literature.