Traditionally, faith and reason have each been considered to be sources of justification for religious belief. Because both can purportedly serve this same epistemic function, it has been a matter of much interest to philosophers and theologians how the two are related and thus how the rational agent should treat claims derived from either source. Some have held that there can be no conflict between the two—that reason properly employed and faith properly understood will never produce contradictory or competing claims—whereas others have maintained that faith and reason can (or even must) be in genuine contention over certain propositions or methodologies. Those who have taken the latter view disagree as to whether faith or reason ought to prevail when the two are in conflict. Kierkegaard, for instance, prioritizes faith even to the point that it becomes positively irrational, while Locke emphasizes the reasonableness of faith to such an extent that a religious doctrine’s irrationality—conflict with itself or with known facts—is a sign that it is unsound. Other thinkers have theorized that faith and reason each govern their own separate domains, such that cases of apparent conflict are resolved on the side of faith when the claim in question is, say, a religious or theological claim, but resolved on the side of reason when the disputed claim is, for example, empirical or logical. Some relatively recent philosophers, most notably the logical positivists, have denied that there is a domain of thought or human existence rightly governed by faith, asserting instead that all meaningful statements and ideas are accessible to thorough rational examination. This has presented a challenge to religious thinkers to explain how an admittedly nonrational or transrational form of language can hold meaningful cognitive content.