Human Nature Bias

Rationality is founded on what we find believable. Likewise, fideism is founded on what we find believable. What do we find believable? Where does that come from?

One answer is biology. Our brains are the way they are, so that is why we find certain things believable, and other things not believable. I don't think human nature is inherently biological, but it does seem that by altering the brain, we can alter even that non-biological reality (there's a tight correlation between brain and consciousness).

To the extent that the brain can be altered by people, we could alter what is believable. (If there's some aspect of human nature that does not respond to brain manipulation and that does respond to some other manipulation, then that too can be altered.) This would be a form of "overcoming bias", overcoming "human nature bias". But if we could overcome bias to an arbitrary degree, what should be believable? For whatever answer to that last question, how do we know that?

Maybe we could say that we should find believable that which promotes survival. If we didn't survive, we wouldn't exist. So, why should human existence be a criterion for what's believable? We have a strong survival bias. But why not overcome that bias? We also have a strong anti-pain bias. I can see that we probably would always choose to have that one. But should we? Do beliefs that follow anti-pain bias actually connect us with reality and thus tell us which beliefs should be believable? It might fit us for reproduction and to fit into our environments (or to bend in favor of whatever is using pain to control us), but why do we think that connects us to reality? Where does our concept of reality (i.e., the definition of the word) even come from?

But somehow we know that things matter and thus that there is such a thing as the truth / that which ought to be found believable. This is something we know as persons, even starting out from the Cartesian starting point. It's how we start out from that position.

It's somewhat like how we know that there is such a thing as morality, even if we tend to struggle to ground morality rationally. Maybe there is a set of valid believabilities, just like there could be a set of valid moral duties. In both cases, we would have to ground their validity in something that was not rooted in human nature. It would have to be rooted in "should" of some kind. What kind of ought can transcend human nature, and lay claim to being ultimate? Can we know anything about this ought, which would help us to know what we ought to find believable? Does this ought give us a reason to trust our existing believabilities, and to what extent?

If this ought is conscious, and a person, who values us, who is the seat of trustworthiness, who to a great extent understands simantic words the way we do, then we can know and trust this ought-person to speak reality to us in a basically trustworthy way, and there is a reason for our believabilities to be valid, and even for our alterations of our believabilities to be potentially valid, as long as they are compatible with belief in that ought.

But maybe there is some other explanation. Could ought be something impersonal? How much can we know about an impersonal ought, one which does not reduce to human nature? Can we know enough to validate any of our natural believabilities, and guide us as we gain the ability to change human nature?