Fundamentalist religions (forms of authoritarian mysticism founded on a toxic wedding of textual foundationalism and illuminationism) such as Christianity and Islam) tell us:
You need faith.
But this faith requires knowledge, which requires justification, which requires certainty, which requires epistemic closure, which requires (I argue) propositions that are either analytic or a priori or both.
We can know that 1 + 1 = 2 because it is true by definition (analytic) and you can know that you exist a priori because doubting your own existence necessarily presupposes a doubter. Basically, all we can really know is that which cannot be false by definition or which cannot be doubted without resulting in logical contradiction.
What I propose, following the “right”-wing pragmatism of Nicholas Rescher, C.S. Peirce and Susan Haack (and Roy Bhaskar’s critical realism gets an honorable mention) is an extreme form of scientific fallibilism (we might always be wrong about any scientific theory that is not analytic and/or a priori) but also a form of realism which states that we do have indirect access to an objectively real world. We do not unmediated access to it because our access to it is always perspectival, mediated by senses, culture, language, and other elements that make our rationality “bounded”, in the words of Herbert A. Simon.
As I like to put it, epistemological reliability is the difference between our faculties and their limitations. This, I think, is a succinct way of describing the intuitive doubt non-fundamentalists (and I don’t consider myself an atheist) have when they think “how can we possibly know which religion is correct, especially given the impossible epistemological demands of certainty that these religions impose?”
We can’t! Doubt cannot exist alongside knowledge, because knowledge presupposes certainty. Where there is doubt, we cannot be said to know something because there is always the possibility that the proposition in question can be disproven in the future.
To be sure, scientific theories like gravity or evolution have a great deal going for them, and any scientific theory which would contradict them labors under a tremendous burden of truth, but I hold that because these theories are neither analytic nor a priori, we cannot be said to “know” them in the same way that we can know that we exist or that 1+1=2.
In light of this, prayer and religious communion in forms of religious fundamentalism only ever function as a form of doubt suppression rather than knowledge acquisition or cultivation, and the use of non-rational and purely psychological (rather than epistemologically warranted or justifiable) means of suppressing doubt ought to be met, obviously, with a great deal of suspicion.
To put this in more existentially pressing terms, the New Testament teaches that it is possible to know that you are saved. But it also warns you that you may, at some point in the future, begin to evince behavior that is not characteristic of a believer and may either lose your salvation (as in soteriological synergism) or prove you were never really saved in the first place (as in monergism).
Obviously, knowledge that one will not renounce one’s own faith in the future is impossible because it is neither analytic nor a priori and can therefore conceivably be falsified (and often is in many cases) in the future, and knowledge that you might not necessarily be saved in the present means that all you can be certain of is the uncertainty of your future eschatological state. For this reason, the ideas that you can know that you are saved or that you can know that the God of the New Testament does exist, are both false utterances that proceed from a text that purports to be infallibly true, and these religious beliefs are therefore self-refuting.
Be open-minded, but only to open systems. Don’t be open-minded to the adoption of closed systems because then your mind becomes a closed system, even though closed systems might have their broken-clock insights. A mind open to open systems is itself an open system and learning is itself the product of an open system by its nature.
A fundamentalist may claim that the so-called open-minded person is ironically closed-minded because he repudiates the possibility of a form of authoritarian mysticism as a candidate of knowledge, but open minds are only truly open only when they are authentically open systems which take seriously the possibility that they have incorrect beliefs about things (something which authoritarian mysticism or fundamentalism does not allow per its combination of textual foundationalism and illuminationism).
So this idea of “be open to whatever is not closed” is not a logical contradiction in which an axiom is self-refuting. I am reminded of this idea that the logical positivist insistence that knowledge acquisition can only proceed through empiricism is not itself an empirical axiom but a foundational one, so its whole system is self-refuting. I consider myself a radical empiricist that is open not only to the digital empiricism of logical positivism but the analogue empiricism of the intuitive found in mysticism, and I consider my principle “I only consider empirical evidence legitimate” an axiom that produces algorithms that simply does not seek theoretical completeness. It is a description of the kind of behavior a certain kind of organism engages in and not a logical system in need of theoretical completeness (and where such internal consistency in the form of completeness competes with the knowledge empiricism acquires through correspondence, I certainly prefer the latter).