I'd recommend two books by the Christian philosopher William Alston:
_Perceiving God: The Epistemology of Religious Experience_ (Ithaca: Cornell
University Press, 1991), and _The Reliability of Sense Perception_
(Ithanca: Cornell University Press, 1996).
In case you do not have access to either, here is a very brief summary of
Alston is concerned with the reliability of a doxastic (belief-formation)
practice for which sense perceptions are the data. "The practice of
forming perceptual beliefs about the physical environment on the basis of
sensory experience (together, sometimes, with suitable background beliefs)
we may term 'sense-perceptual practice.'" (PG 103) "Sense-perceptual
practice" (SP) is his concern. He shows that there is no
non-question-begging way of showing that SP is justified as a practice for
getting us to the truth, but he maintains nevertheless that it is still
rational to engage in SP:
"It is a kind of practical rationality that is in question here. In
reflecting on our situation--what considerations are available to us, what
we can and can't know, can and can't prove, what alternatives are open to
us--we come to realize that we are proceeding rationally in forming and
evaluating beliefs in ways that are established in our society and that are
firmly embedded in our psyches. Or rather it is prima facie rational for
us to proceed in this way, with this initial presumption subject to being
overridden or strengthened. . ." (PG 168).
"When a doxastic practice has persisted over a number of generations, it
has earned the right to be considered seriously. . . But there are no such
grounds for presumption in the case of idiosyncratic practices. Hence we
will proceed more reasonably, as well as more efficiently, by giving
initial, ungrounded credence only to socially established practices" (PG 170).
Here we have Alston's answer to a question that has often been directed at
his theory, the question of whether this theory would provide justification
for any and all beliefs, no matter how irrational. This simply is not the
case. The claims of every new religious cult, every new social or
psychological theory, every psychotic, are not granted the presumption of
credence. The plural and public nature of doxastic practice make it
rational to accept some and reject other claims.
Alston concludes this discussion of the rationality of SP:
"To summarize, it is prima facie rational to engage in established doxastic
practices. . . . To put it in a formula, a firmly established doxastic
practice is rationally engaged in unless the total output of all our firmly
established doxastic practices sufficiently indicates its unreliability"
Why all of this? First, and as developed further in _The Reliability of
Sense Perception_, Alston wants to show that, in spite of our empirical
tendencies, empiricism is rather problematic, but its sense-perceptual
source can be "rescued" in a certain way. It is rational to believe that
the deliverances of our senses are reliable (given certain positive
epistemic conditions) and that empirical beliefs grounded in sense
perception are justified. But then he claims that religious experience is
reliable in the same way, and religious beliefs grounded in religious
experience are likewise justified.
But since both sense-perceptual practice (SP) and "mystical-perceptual
practice" (MP) are "common doxastic practices," both are on an equal
footing as far as conveying justification to the beliefs to which they
contribute evidence. But so far, at least, an idiosyncratic practice such
as "UFO-perceptual practice" does not have the track record, the
commonality of either SP or MP, and thus it should not be regarded as
Alston's arguments have been well-received among epistemologists and are, I
think, successful. The arguments do give us a way of evaluating the
relative justification of Price's and Mother Theresa's beliefs based on
their respective experience.
I hope this is helpful rather than confusing.
Department of Philosophy
University of Colorado-Boulder