TL;DR
Based on what I managed to investigate, epistemological positions on the role of reason and evidence in establishing the existence of God can be broadly categorized into the following:
- Natural Theology
- Fideism
- Classical Apologetics
- Evidential Apologetics
- Presuppositional Apologetics
- Reformed Epistemology
- Mysticism
While I couldn't find specific statistics, the diversity of viewpoints suggests a lack of clear consensus on these positions.
Natural Theology
Natural theology, once also termed physico-theology, is a type of theology that seeks to provide arguments for theological topics (such as the existence of a deity) based on reason and the discoveries of science, the project of arguing for the existence of God on the basis of observed natural facts, and through natural phenomena viewed as divine, or complexities of nature seen as evidence of a divine plan (see predestination) or Will of God, which includes nature itself.
This distinguishes it from revealed theology, which is based on scripture and/or religious experiences, also from transcendental theology, which is based on a priori reasoning. It is thus a type of philosophy, with the aim of explaining the nature of the celestial motors, or gods, or of one supreme god, that are responsible for heavenly motion. Aristotle's tractate on metaphysics claims to demonstrate the necessary existence of an unmoved prime mover.
(Source: Natural theology - Wikipedia)
Natural theology is a program of inquiry into the existence and attributes of God without referring or appealing to any divine revelation. In natural theology, one asks what the word “God” means, whether and how names can be applied to God, whether God exists, whether God knows the future free choices of creatures, and so forth. The aim is to answer those questions without using any claims drawn from any sacred texts or divine revelation, even though one may hold such claims.
For purposes of studying natural theology, Jews, Christians, Muslims, and others will bracket and set aside for the moment their commitment to the sacred writings or traditions they believe to be God’s word. Doing so enables them to proceed together to engage in the perennial questions about God using the sources of evidence that they share by virtue of their common humanity, for example, sensation, reason, science, and history. Agnostics and atheists, too, can engage in natural theology. For them, it is simply that they have no revelation-based views to bracket and set aside in the first place.
This received view of natural theology was a long time in the making. Natural theology was born among the ancient Greeks, and its meeting with ancient Judeo-Christian-Muslim thought constituted a complex cultural event. From that meeting there developed throughout the Middle Ages for Christians a sophisticated distinction between theology in the Christian sense and natural theology in the ancient Greek sense. Although many thinkers in the Middle Ages tried to unite theology and natural theology into a unity of thought, the project frequently met with objections, as we shall see below. The modern era was partly defined by a widespread rejection of natural theology for both philosophical and theological reasons. Such rejection persisted, and persists, although there has been a significant revival of natural theology in recent years.
(Source: Natural Theology - Internet Encyclopedia of Philosophy)
Fideism
“What indeed has Athens to do with Jerusalem?” (246) This question of the relation between reason – here represented by Athens – and faith – represented by Jerusalem – was posed by the church father Tertullian (c.160–230 CE), and it remains a central preoccupation among contemporary philosophers of religion.
“Fideism” is the name given to that school of thought – to which Tertullian himself is frequently said to have subscribed – which answers that faith is in some sense independent of, if not outright adversarial toward, reason. In contrast to the more rationalistic tradition of natural theology, with its arguments for the existence of God, fideism holds – or at any rate appears to hold (more on this caveat shortly) – that reason is unnecessary and inappropriate for the exercise and justification of religious belief. The term itself derives from fides, the Latin word for faith, and can be rendered literally as faith-ism. “Fideism” is thus to be understood not as a synonym for “religious belief,” but as denoting a particular philosophical account of faith’s appropriate jurisdiction vis-a-vis that of reason.
(Source: Fideism - Stanford Encyclopedia of Philosophy)
An example of Fideism: Blaise Pascal
Another form of fideism is assumed by Pascal's Wager, which is a rational argument for a pragmatic view of God's existence. Blaise Pascal invites the atheist considering faith to see faith in God as a cost-free choice that carries a potential reward. He does not attempt to argue that God indeed exists, only that it might be valuable to assume that it is true. Of course, the problem with Pascal's Wager is that it does not restrict itself to a specific god, although Pascal did have in mind the Christian version (referred to both by Jews and Christians as God), as is mentioned in the following quote. In his Pensées, Pascal writes:
Who then will blame Christians for not being able to give reasons for their beliefs, since they profess belief in a religion which they cannot explain? They declare, when they expound it to the world, that it is foolishness, stultitiam; and then you complain because they do not prove it! If they proved it, they would not keep their word; it is through their lack of proofs that they show they are not lacking in sense.
— Pensées, no. 233
Pascal, moreover, contests the various proposed proofs of the existence of God as irrelevant. Even if the proofs were valid, the beings they propose to demonstrate are not congruent with the deity worshiped by historical faiths, and can easily lead to deism instead of revealed religion: "The God of Abraham, Isaac, and Jacob—not the god of the philosophers!"
(Source: Fideism#Blaise_Pascal_and_fideism - Wikipedia)
Classical apologetics
Classical apologetics is a method of apologetics that begins by first employing various theistic arguments to establish the existence of God. Classical apologists will often utilize various forms of the cosmological, teleological (Design), ontological, and moral arguments to prove God’s existence. Once God’s existence has been established, the classical apologist will then move on to present evidence from fulfilled prophecy, the historical reliability of Scripture, and the bodily resurrection of Jesus to distinguish Christianity from all other competing forms of theism.
Classical apologetics (also known as traditional apologetics) has as its distinctive feature a two-step approach to establishing a Christian worldview. Classical apologists are often hesitant to make an argument directly from miracles to the biblical God. Rather, they prefer to appeal to miracles after having already established a theistic context. Modern proponents of classical apologetics include R.C. Sproul, William Lane Craig, and Norman Geisler.
Christian philosopher Norman Geisler summarized the difference between classical and evidential apologetics in this way: "The difference between the classical apologists and the evidentialists on the use of historical evidences is that the classical see the need to first establish that this is a theistic universe...The basic argument of the classical apologist is that it makes no sense to speak about the resurrection as an act of God unless, as a logical prerequisite, it is first established that there is a God who can act" (Baker Encyclopedia of Christian Apologetics).
(Source: What is classical apologetics? - GotQuestions)
Evidential apologetics
Evidential apologetics is a method of Christian apologetics that emphasizes positive evidences in favor of the truth of Christianity. The distinctive feature of evidential apologetics is its one-step approach to establishing Christian theism. Evidentialists will utilize evidence and arguments from several areas including archeology, fulfilled messianic prophecy, and especially from miracles.
In distinction from classical apologetics, the evidential apologist believes that the occurrence of miracles acts as an evidence for God’s very existence. In this way, the evidential apologist does not believe that the philosophical and scientific arguments for God’s existence must logically precede arguments from miracles to establish biblical Christianity. However, the evidential apologist is not opposed to the use of natural theology to help to confirm God’s existence. These arguments are an important weapon in the arsenal of the evidentialist as they help to undergird the case for Christianity by giving further confirmation that God exists and has created and designed our universe. Evidentialists simply do not believe such arguments must be presented prior to moving on to evidence from miracles. In this way, the evidential apologist can argue for theism and Christian theism at the same time without having to first establish God’s existence. Such an approach can be beneficial in personal evangelism where time can be at a minimum.
Evidential apologists characteristically place a heavy emphasis on evidence from miracles, especially the bodily resurrection of Jesus Christ. Evidentialists will appeal to numerous lines of evidence to establish the historicity of the post-mortem appearances of the risen Jesus, as well as the discovery of His empty tomb. Additional emphasis is often placed on refuting naturalistic theories that attempt to explain away the evidence for the resurrection of Christ. Once the resurrection has been established, Jesus’ (and His apostles’) own understanding of this event then becomes the proper interpretive framework through which we understand its significance. Prior to His crucifixion, Jesus said that His forthcoming resurrection would validate His claims (Matthew 12:38-40, 16:1-4). The Apostle Paul declared that the resurrection of Christ was God’s vindication of Christ’s deity (Romans 1:3-4). In the book of Acts, the Apostle Peter claimed that Jesus’ bodily resurrection was God’s endorsement of Jesus’ public ministry (Acts 2:23-32). When taken in this context, the bodily resurrection becomes the primary validation of Jesus’ own radical claims about Himself and the vindication of Jesus’ message of salvation.
(Source: What is evidential apologetics? - GotQuestions)
Presuppositional apologetics
Presuppositional apologetics is an approach to apologetics which aims to present a rational basis for the Christian faith and defend it against objections by exposing the logical flaws of other worldviews and hence demonstrating that biblical theism is the only worldview which can make consistent sense of reality.
Presuppositional apologetics does not discount the use of evidence, but such evidences are not used in the traditional manner—that is, an appeal to the authority of the unbeliever’s autonomous reason. Presuppositional apologetics holds that without a Christian worldview there is no consistent basis upon which to assume the possibility of autonomous reason. When the materialist attempts to refute Christianity by appeal to deductive reason, he is, in fact, borrowing from the Christian worldview, hence being inconsistent with his stated presuppositions.
The presuppositional approach to apologetics calls for the Christian and non-Christian to engage in an internal examination of their respective worldview and thus determine whether or not they are internally consistent. The essence of presuppositional apologetics is an attempt to demonstrate that the non-Christian’s worldview forces him to a state of subjectivity, irrationalism, and moral anarchy.
Since the unbeliever’s worldview is objectively false, by necessity it contains demonstrable contradictions (e.g., he makes moral judgments, but he cannot account for moral absolutes without the Christian/theistic worldview). The believer, within the Christian framework, can account for things like rationality, logic, uniformity of nature, morality, science, etc., because the Christian worldview conforms to a transcendent reality.
In summary, the presuppositional apologist engages in an internal critique of a given worldview in order to demonstrate that it is arbitrary, inconsistent within itself, and lacks the preconditions for epistemology. The presuppositional apologist can thus take a given value which is held by the unbeliever and demonstrate to him that if his own worldview were true, that very belief would be incoherent and/or meaningless. Presuppositional apologetics seeks to prove Christianity with reference to the impossibility of the contrary. In other words, unless the Christian worldview is presupposed—whether at a conscious or subconscious level—there is no possibility for proving anything.
(Source: What is presuppositional apologetics? - GotQuestions)
Reformed Epistemology
In the philosophy of religion, Reformed epistemology is a school of philosophical thought concerning the nature of knowledge (epistemology) as it applies to religious beliefs. The central proposition of Reformed epistemology is that beliefs can be justified by more than evidence alone, contrary to the positions of evidentialism, which argues that while non-evidential belief may be beneficial, it violates some epistemic duty. Central to Reformed epistemology is the proposition that belief in God may be "properly basic" and not need to be inferred from other truths to be rationally warranted. William Lane Craig describes Reformed epistemology as "One of the most significant developments in contemporary religious epistemology ... which directly assaults the evidentialist construal of rationality."
(Source: Reformed epistemology - Wikipedia)
Reformed epistemology is a thesis about the rationality of religious belief. A central claim made by the reformed epistemologist is that religious belief can be rational without any appeal to evidence or argument. There are, broadly speaking, two ways that reformed epistemologists support this claim. The first is to argue that there is no way to successfully formulate the charge that religious belief is in some way epistemically defective if it is lacking support by evidence or argument. The second way is to offer a description of what it means for a belief to be rational, and to suggest ways that religious beliefs might in fact be meeting these requirements. This has led reformed epistemologists to explore topics such as when a belief-forming mechanism confers warrant, the rationality of engaging in belief forming practices, and when we have an epistemic duty to revise our beliefs. As such, reformed epistemology offers an alternative to evidentialism (the view that religious belief must be supported by evidence in order to be rational) and fideism (the view that religious belief is not rational, but that we have non-epistemic reasons for believing).
Reformed epistemology was first clearly articulated in a collection of papers called Faith and Rationality edited by Alvin Plantinga and Nicholas Wolterstorff in 1983. However, the view owes a debt to many other thinkers.
(Source: Reformed Epistemology - Internet Encyclopedia of Philosophy)
Mysticism
Under the influence of William James’ Varieties of Religious Experience, philosophical interest in mysticism has heavily focused on distinctive, allegedly knowledge-granting “mystical experiences.” Philosophers have dealt with such topics as the classification of mystical experiences, their nature, to what extent mystical experiences are conditioned by a mystic’s language and culture, and whether mystical experiences furnish evidence for the truth of mystical claims. Some philosophers have recently questioned the emphasis on experience in favor of examining broader mystical phenomena. Indeed, “mysticism” is best thought of as a constellation of distinctive practices, discourses, texts, institutions, traditions, and experiences aimed at human transformation, variously defined. But this entry will concentrate on the topics philosophers have discussed concerning mystical experiences.
[...]
Various philosophers have defended the evidential value, to one degree or another, of some religious and mystical experiences, principally with regard to experiences of God (see Baillie 1939, Broad 1953, Davis 1989, Gellman 1997 and 2001a, Gutting 1982, Swinburne 1991 and 1996, Wainwright 1981, Yandell 1993). These philosophers have stressed the “perceptual” nature of experiences of God. This approach can be summarized as follows:
Experiences of God have a subject/object structure with a phenomenological content allegedly representing the object of the experience. Subjects are also moved to make truth claims based on such experiences. Furthermore, there are mystical procedures for getting into position for a mystical experience of God (see Underhill 1911 [1945, 90–94]), and others can take up a suitable mystical path to try to check on the subject’s claims (see Bergson 1977, 210). In all these ways, experiences of God are perceptual in nature.
Such experiences count as at least some evidence in favor of their own validity. That a person seems to experience some object is some reason to think he or she really does have experiential contact with it. Thus, experiences of God count as at least some evidence in favor of their own validity.
Agreement between experiences of people in different places, times, and traditions enhances the evidence in favor of their validity (see Broad 1953). Hence, agreement about experiences of God in diverse circumstances enhances the evidence in their favor. (But see Section 9.6.)
Further enhancement of the validity of a mystical experience can come from appropriate consequences in the life of the person who had the experience, such as increased saintliness (see Wainwright 1981, 83–88). William James proposed a pragmatic “fruit” test for determining true mystical doctrines (James 1958, 368): if a mystical experience produces positive results in how one leads one’s life, then the experience is authentic and the way of life one follows is vindicated, and so the teachings leading to the positive life are correct. In short, the “truth” of one’s beliefs are shown by one’s life as a whole. (But what is considered positive fruit in one mystical tradition may not be considered so in another.)
(1)–(4) yield initial evidence in favor of the validity of (some) experiences of God.
(Source: Mysticism - Stanford Encyclopedia of Philosophy)
