 ‘Reformed’ epistemologists have appealed to an externalist epistemology in order to maintain that theistic belief may be justified even though its truth is no more than basically evident to the believer—that is, its truth is not rationally inferable from other, more basic, beliefs, but is found to be immediately evident in the believer’s experience (see Plantinga and Wolterstorff 1983, Alston 1991, Plantinga 2000). On Plantinga’s version, (basic) theistic beliefs count as knowledge because they are produced by the operation of a special cognitive faculty whose functional design fits it for the purpose of generating true beliefs about God. Plantinga calls this the sensus divinitatis, using a term of Calvin’s. (For discussion of the extent to which Plantinga’s use of this term conforms to Calvin’s own usage see Jeffreys 1997 and Helm 1998.) This quasi-perceptual faculty meets functional criteria as a mechanism that, when functioning in the right conditions, confers ‘warrant’ (where warrant is whatever must be added to true belief to yield knowledge) and, granted theism’s truth, it probably yields ‘basic’ knowledge because God designs it just for that purpose. In defence of specifically Christian belief, Plantinga argues that the same warrant-conferring status belongs to the operation of the Holy Spirit in making the great truths of the Gospel directly known to the believer.