 Another influential type of challenge to obligatory belief assessment in the face of religious diversity has been raised by Jerome Gellman. The focus of his challenge centers on what he identifies as rock bottom beliefs. Such beliefs, as Gellman defines them, are the epistemic givens in a religious belief system—the assumed, foundational truths upon which all else is built. Gellman grants that if a religious belief affirmed by an exclusivist is not rock bottom (is not a foundational assumption), then it may well be subject to obligatory belief assessment in the face of religious diversity. However, he argues, since belief assessment only makes sense when one isn’t certain that the belief in question is true, and since rock bottom religious beliefs are among the foundational truths—the basic, assumed truths—in an exclusivist’s epistemic system, no assessment is necessary. Rather, when exclusivists encounter a challenge to such a belief—for example, a challenge to their rock bottom belief in God’s ultimate control over all earthly affairs—they can, utilizing the G. E. Moore switch, justifiably maintain that because their rock bottom belief is true, the competing belief can justifiably be rejected (Gellman 1993, 345–364; Gellman 1998, 229–235).