Clearly, if an “idiot” lacks the cognitive capacity to make a proper distinction between an adequate demonstration of something that can in fact be shown to be true for all of us, and one that cannot, then that is in fact the case.
This can be demonstrated.
Instead, my point revolves more around those interactions in which a rational mind is able to demonstrate [re mathematics, the laws of physics, empirical facts, logical rules of language etc., in the either/or world] that something is true to other rational people, and those interactions [re moral and political narratives in the is/ought world] in which “truth” is more likely to be one or another “existential contraption” rooted in dasein, conflicting goods and political economy.
The village idiot can argue [and then try to demonstrate] that an abortion involves extracting the unborn baby through the nostrils, but how would one be construed as an idiot when the argument shifts to the morality of abortion?
How, in the absence of God, can rationality and virtue be established by mere mortals?
That you want to believe this I don’t doubt. But I do not toss everything into the garbage bin. I make that distinction between what is able to be demonstrated as true for all of us in the either/or world and what is entirely more problematic in the is/ought world.
And I still suspect that you believe of me what you do because on some cognitive level you recognize what is at stake if I ever do manage to yank you down into my dilemma before you manage to yank me up out of it instead.