I used to think that one could take from Descartes’ meditations a relatively good pragmatic-epistemological argument for believing in God, since there is no possibility of ‘knowing’ anything unless God exists, and provides reliabilism. If God exists then, Descartes argues, he would not allow us to err without providing a way for us to correct ourselves. Of course, whether Descartes can ‘know’ that is itself easy to call into question, but even supposing for the sake of argument that he could know it, it would seem to entail that we are not guaranteed to be correct about any particular thing (other than that ‘I’ exist, and that God exists, and other than that God would not allow me to err without providing me a way to correct myself) at any time tx, so that at no time can I appeal to reliabilism to say that I ‘know’ anything. My knowledge will be probabilistic at best, since even if I am completely convinced of some proposition’s truth, impressed by it’s self-evidence (etc.), it is still the case that I have no guarantee that I know it. The exceptions might be things like that I exist and that God exists. Indeed, if free will is taken seriously, then isn’t there a logically possible world in which one free agent forces another to be subject to the ‘brain in the vat’ experiment? That would mean I might be a brain in a vat thinking of true propositions that they are false, and/or of false ones that they are true, with no way to correct myself in various matters.
However, though this poses a problem, I think perhaps it suggests that epistemology really has to begin with religious disposition. Once one works their way up in ‘first-philosophy’ to that the ‘I’ exists, and that God (that-than-which-nothing-greater-could-be-conceived) exists, then one has to decide what attitude to take to all other impressions, whether they will choose an attitude of love, which reaches out towards the world, trusting God, or else not. This comes from the Medieval epistemologies, which seemed to suggest that man’s ‘knowing’ something was a result of conforming himself to that thing in love by reaching out to it and ‘communing’ with it. This is overly simplified perhaps, but maybe there’s something fundamentally insightful here which we’ve forgotten – I think that ‘religious’ epistemology is in some way perhaps the ‘first-epistemology’ of first philosophy. That would make Bonaventure’s Itinerarium Mentis ad Deum the kind of epistemic orientation which properly orders man towards the objects of knowledge.