In my last post I proposed some ways of looking at this question, and tried to unpack what I thought it was asking you to do. I discussed the sceptical challenge which forms the basis of the question – that other explanations for religious experience will always be more plausible because they would have more empirical backing – this is essentially a reductionist challenge: “Nowadays we know that science can explain all that”, as Caroline Franks Davies puts it.
But can science explain all that? We need to take a step back into epistemology to work out the answer to that. Swinburne’s principle of credulity (it is a principle of rationality that if it seems to a subject that x is present, (in the absence of special considerations) then x probably is present) makes experience innocent until proven guilty and thus turns the table on the sceptic. Notice that it is a principle of rationality. All experience is subsumed under this principle – we just find we must operate as if it were the case – no philosopher has yet managed to provide inductive justification for our confidence in our experiences, memories and reasoning processes, but that is no reason to become sceptical about them. Notice also that there can be no proof for such a principle of rationality, because any attempt to prove it would use just the processes and experiences which are under consideration, and thus would be viciously circular. So the principle of credulity, as a principle of rationality, operates somewhat like an axiom does in maths, in that we have to assume its truth in order to get anywhere.
Now all this means is that the sceptic cannot just dismiss all religious experiences out of hand as not having inductive evidence to back them up like normal experience – as all experiences which generate beliefs are initially granted credulity. If we decide later to discount an experience because it could be shown that such an experience was unreliable, then that is not a problem – therefore things like dreams and hallucinations have become known to be unreliable and so we apply what Swinburne calls the special considerations.
So the principle of credulity is not a license to be gullible – just a placing of the onus on the sceptic to show why an experience is not veridical, rather than an assumption that because an experience doesn’t meet certain criteria of validity, it cannot therefore be veridical.
Swinburne recognises certain limitations on the principle of credulity called subject-related challenges – these include reductionist and conflicting claims challenges. These special considerations include things such as; the subject has been shown to be unreliable in the past, or was in a certain state, or had a certain cultural background or psychological mindset such that it is very unlikely experiences under those circumstances were veridical, or that it is very likely the subject would have had the experience whether the supposed percept (the thing perceived) was there or not.
It is worth noting that when it comes to reductionist challenges, they are recognised as presenting problems for arguments from religious experience. Caroline Franks Davies doesn’t think a pragmatic approach like James works either – she says
“the ‘fruits not roots’ approach to religious experience is not so successful, since the way an experience is caused and its veridicality are inextricably linked. An argument from religious experience cannot be built on experiences which have therapeutic value but no evidential force”
However, she doesn’t think reductionist challenges present insuperable difficulties for arguments from religious experience. She examines various reductionist explanations for religious experience such as hypersuggestibility, deprivation, sexual frustration, regression and mental illness, and concludes that there is not enough evidence to conclude that any of these are correlated with religious experience. She concludes that such reductionist challenges are unlikely to succeed on their own.