The epistemology of religion, as practiced by philosophers, is seldom concerned with the sorts of epistemological questions that emerge on a practical level in ordinary religious life, such as how to determine the correct interpretation of a scriptural text or how to know whether someone's claim to special divine guidance is to be credited. Rather, it tends to focus on the epistemic evaluation of the most basic tenets of the religious worldview in question—the existence of God, the creation of the world and God's relation to it, and the possibility of recognizing divine action in the world and divine revelation. From the 1960s on, religious epistemology has been characterized by a marked decline of fideism, with a renewal of interest in evidentialism and an even more pronounced upsurge of what may be termed experientialism.
Fideism is best characterized as the view that one's basic religious beliefs are not subject to independent rational evaluation. It is defended by urging that religious convictions are the most basic part of a believer's worldview and thus more fundamental than anything else that might be used to evaluate them. It is also said that to evaluate religious beliefs by standards other than the internal standards of the religious belief system itself is in effect to subject God to judgment and is thus a form of idolatry. In the mid-twentieth century fideism took two main forms, existentialism and Wittgensteinian fideism. In the succeeding decades philosophical existentialism has suffered a massive decline, as has its theological counterpart, neoorthodoxy. Wittgensteinian fideism, on the other hand, arose largely in response to the positivist contention that God-talk is cognitively meaningless; with the defeat of positivism it has lost much of its relevance. Many religious thinkers, freed from the need to defend religion's cognitive meaningfulness, have felt a renewed impulse to contend for the truth of their faith. And on the other hand, critics of religion have moved readily from the contention that belief in God is meaningless to the logically incompatible assertion that it is false and/or lacking in evidential support.
Evidentialism is the view that religious beliefs, in order to be rationally held, must be supported by other things one knows or reasonably believes to be true. Evidentialist defenses of religion typically rely heavily on theistic arguments, and all of the classical arguments saw renewed interest in the late twentieth century. Versions of the ontological argument propounded by Charles Hartshorne, Norman Malcolm, and Alvin Plantinga are clearly valid, though their premises remain controversial. William Rowe's work has directed renewed attention to the Clarke-Leibniz version of the cosmological argument, and new versions of the design argument teleological argument for the existence of God, focusing on God as the source of the basic laws of nature, have been developed by Richard Swinburne and others. Even the moral argument (Robert Adams) and the argument from religious experience (Gary Gutting) have come in for renewed attention. Two new arguments, or versions of arguments, are keyed to developments in cosmology. The "kalam cosmological argument" (William Craig) uses big-bang cosmology to argue that the physical universe as a whole has a temporal beginning and thus is in need of an external cause. And the anthropic cosmological principle is used by John Leslie, among others, to support a new version of the design argument: The apparent fact that the basic laws and initial conditions of the universe are "fine tuned" for life, with no apparent scientific explanation for this fact, is taken as evidence of intelligent design. Both of these arguments benefit from their association with cutting-edge science but also in consequence become vulnerable to future changes in scientific thinking on cosmology.
Evidentialist arguments against religion take a variety of forms. Most basically, evidentialists argue that the theistic arguments are unsuccessful and that theism fails for lack of evidential support. There are various challenges to the coherence and logical possibility of the traditional divine attributes. In most cases, however, these arguments, if successful, lead to a reformulation of the attributes in question rather than to the defeat of theism as such. But by far the most active area of consideration for antireligious evidentialism has been the problem of evil; the volume of writing on its various forms, by both critics and believers, has probably exceeded that on all of the theistic arguments taken together.
Along with the renewed consideration of the various arguments there have been reflections on the requirements for a successful argument. Traditional natural theology claimed to proceed from premises known or knowable to any reasonable person (e.g., "Some things are in motion") by means of arguments any reasonable person could see to be valid. By these standards it is not difficult to show that all of the arguments fail. But the standard is clearly too high; it is difficult to find significant arguments in any area of philosophy that meet it. No doubt a good argument should not be circular or question begging, and its premises must enjoy some kind of support that makes them at least plausible. But what seems plausible, or even evidently true, to one person may not seem so to another, equally rational, person; thus, the recognition emerges that arguments and proofs may be "person-relative" (Mavrodes 1970).
Furthermore, even a good argument is not necessarily decisive by itself, so it is necessary to consider the ways in which a number of arguments, none of them in itself conclusive, can lend their combined weight to establishing a conclusion. One model for this has been developed by Basil Mitchell, who compares arguments for religious beliefs to the kinds of cumulative-case arguments found in fields such as history and critical exegesis as well as in the choice between scientific paradigms. Richard Swinburne, by contrast builds a cumulative case for divine existence using the mathematical theory of probability. While it is not possible to assign precise numerical probabilities to the propositions involved in theistic argumentation, Bayes's theorem does provide insight into the way in which evidence contributes in a cumulative fashion to the support or defeat of a hypothesis such as theism Bayesianism. In addition, John L. Mackie and Michael Martin have developed what are in effect cumulative-case arguments for atheism.
The most significant development in the epistemology of religion during the 1980s and early 1990s was the rise of a new type of theory distinct from both fideism and evidentialism. This theory, found in the writings of Richard Swinburne, Alvin Plantinga, and William Alston, lacks a generally recognized label (the term Reformed epistemology properly applies only to Plantinga's version) but may be termed experientialism in view of its emphasis on the grounding of religious belief in religious experience. Experientialism differs from fideism in that it does not seek to insulate religious belief from critical epistemic evaluation: rather, it affirms that religious experience can provide a sound epistemic basis for such beliefs. Experientialism is also importantly different from the evidentialist "argument from religious experience" in the following respect: The religious experience is not first described in ontologically neutral terms and then made the basis for an inference to the existence of the religious object. On the contrary, the religious belief is grounded directly in the religious experience, without mediation by inference, just as perceptual beliefs are grounded directly in perceptual experience.
This difference is important for a couple of reasons. For one thing it is more faithful to the phenomenology of both religious and perceptual belief: in typical cases neither form of belief involves such an inference. But more important, the direct grounding of belief in experience offers better prospects of a favorable epistemic status for the resulting beliefs than does the inferential approach. This is readily apparent in the case of perceptual experience: attempts at a "proof of the external world" have been notably unsuccessful, yet only those in the grip of philosophical theory doubt that we do in fact acquire a great deal of knowledge about the world through our perceptual experience. In the same way it is at least conceivable that believers acquire knowledge of God experientially even if no compelling inferential argument from religious experience is available.
Swinburne, Plantinga, and Alston share what may be termed a weak foundationalist approach to epistemology. That is to say, they accept the distinction between "basic" beliefs, which do not derive their rational acceptability from other beliefs, and "derived" beliefs, which gain their support from the basic beliefs. But they do not accept the traditional foundationalist restriction of basic beliefs to those that are nearly or entirely immune to doubt—beliefs that are self-evident, evident to the senses, or incorrigible. Each of them, furthermore, includes some religious beliefs in the category of basic beliefs. The epistemological task, then, is to show that this inclusion is epistemically proper—to show that such religious beliefs are among our "properly basic beliefs." (The terminology is Plantinga's, but the issue is the same for all three thinkers.) Each of them approaches this issue in a different way, though the approaches are ultimately compatible. Plantinga argues, following Roderick Chisholm, that the proper approach to the question of which beliefs are properly basic is inductive: one first conducts an inventory of the beliefs one takes oneself to hold rationally, then eliminates those that derive their epistemic support from other beliefs, and those that remain will be taken as properly basic. The typical Christian believer, Plantinga thinks, will find that she considers her belief in God to be rational but does not ground it inferentially on other beliefs she holds; thus, she will conclude that this is a properly basic belief. To be sure, atheists or believers in other religions will not concur in this, but Plantinga finds this to be unproblematic: "Followers of Bertrand Russell and Madalyn Murray O'Hair may disagree: but how is that relevant? Must my criteria, or those of the Christian community, conform to their examples? Surely not. The Christian community is responsible to its set of examples, not to theirs" (Plantinga and Wolterstorff 1983, p. 78).
In contrast with Plantinga's "internal" justification of the rationality of belief, both Swinburne and Alston attempt to show that religious experiences should have some epistemic weight, even for those who do not share the belief system the experiences ostensibly support. Swinburne appeals to the "principle of credulity," which states that "(in the absence of special considerations) if it seems (epistemically) to a subject that x is present, then probably x is present; what one seems to perceive is probably so" (1979, p. 254). He argues that a general denial of this principle lands us in a "sceptical bog" and that there is no justification for excluding religious experience from its scope.
Alston develops a "doxastic practice" approach to epistemology (indebted to both Thomas Reid and Ludwig Wittgenstein), which holds that all socially established doxastic practices are "innocent until proved guilty"; "they all deserve to be regarded as prima facie rationally engaged in … pending a consideration of possible reasons for disqualification" (1991, p. 153). Alston's delineation of the "Christian mystical practice" and his defense of its epistemic status constitute a systematic, detailed, and highly sophisticated presentation of experientialism.
One major difficulty for experientialism is the existence of incompatible experientially grounded beliefs in different religions—in Alston's terms, the existence of a plurality of mutually incompatible mystical practices. Alston concludes that religious experience alone probably cannot resolve this ambiguity and that "the knowledgeable and reflective Christian should be concerned about the situation … [and] should do whatever seems feasible to search for common ground on which to adjudicate the crucial differences between the world religions, seeking a way to show in a non-circular way which of the contenders is correct. What success will attend these efforts I do not presume to predict. Perhaps it is only in God's good time that a more thorough insight into the truth behind these divergent perspectives will be revealed to us" (1991, p. 278).
Critics, however, have urged more far-reaching objections to the experientialist program. According to Richard Gale, the analogy between religious experience and sense perception is weak, with the dissimilarities far outweighing the similarities. He also argues that religious experience could not be cognitive—that is, could not provide independent grounds for belief in the existence of its object—and that religious objects such as God or the One are not possible objects of perceptual experience, even if they exist. Alston, on the other hand, has argued in detail that the phenomenological structure of religious experience is perceptual and that "mystical perception" constitutes a genuine species of perception along with sense perception.
See also Alston, William P.; Atheism; Bayes, Bayes' Theorem, Bayesian Approach to Philosophy of Science; Chisholm, Roderick; Clarke, Samuel; Cosmological Argument for the Existence of God; Evil, The Problem of; Existentialism; Fideism; Leibniz, Gottfried Wilhelm; Mackie, John Leslie; Malcolm, Norman; Moral Arguments for the Existence of God; Ontological Argument for the Existence of God; Philosophy of Religion; Plantinga, Alvin; Positivism; Probability and Chance; Reid, Thomas; Religious Experience; Religious Pluralism; Teleological Argument for the Existence of God; Theism, Arguments For and Against; Wittgenstein, Ludwig Josef Johann.
Alston, W. P. Perceiving God: The Epistemology of Religious Experience. Ithaca, NY: Cornell University Press, 1991.
Gale, R. M. On the Nature and Existence of God. Cambridge, U.K.: Cambridge University Press, 1991.
Martin, M. Atheism: A Philosophical Justification. Philadelphia: Temple University Press, 1990.
Mavrodes, G. Belief in God: A Study in the Epistemology of Religion. New York: Random House, 1970.
Mitchell, B. The Justification of Religious Belief. New York: Oxford University Press, 1981.
Plantinga, A., and N. Wolterstorff, eds. Faith and Rationality: Reason and Belief in God. Notre Dame, IN: University of Notre Dame Press, 1983.
Swinburne, R. The Existence of God. Oxford: Clarendon Press, 1979.
William Hasker (1996)