It isn't always something subtle, or just in your mind. It can be so blatant it amazes you how you could not have seen it before. And it isn't just something you do, it is something you are. Even doing it requires a new view of the world which much shape your personality. I have seen it, just what people are asking to see before they believe. I have felt it and known it and understood it. I'm an occultist for a reason.
Noone can really know anything, eh? That may be useful for humility, but how useful is it for anything else? How busy are you arguing that you never really know something, unable to actually commit to something and do it? How satisfying can anything be when you know that such a fact is subjective and transitory? Sometimes you should swallow your humble "knowledge" of knowing nothing and "know" things, because you can't do anything without some level of "knowledge."
Christianity talks about faith a lot. Not just believing something like you believe what someone tells you when you trust them, but an absolute, redeeming faith in the truth of something absolute, without proof. Early gnostic branches of Christianity diverged in, among other things, this point. Their namesake, "gnosis," means knowledge. It can be translated as knowledge as in to know a fact, information, or it can be translated as knowledge by means of experience. Like pistis, faith, to Christians, gnosis was a special, absolute and redeeming knowledge. The question is, does the path to salvation, in whatever form it may take, come with faith in the absolute or knowledge of the absolute?