Well, I certainly agree about fallibility. Humans don't have access to infallible epistemologies.
That said, if fasting and prayer reliably gets me the most useful confidence levels in propositions for achieving my goals, then I should engage in fasting and prayer because that's part of the most reliable process for evaluating evidence.
If it doesn't, then that's not a reason for me to engage in fasting and prayer, though I may choose to do so for other reasons.
Either one of those things is true, or the other is. And I may not know enough about the world to decide with confidence which it is (though I sure do seem to), but even if I don't my ignorance doesn't somehow make it the case that they are both true.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.