from what I understand about it, it is they are or we are at that capacity, they don't need to know it or understand it (what ever it is) from birth but they would know and understand it from the first encounter, and be inclined to act in a manner of a stream enterer naturally?
suppose it is like Mozart playing the piano at an early age?
I may be wrong but I think that is accurate?
He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them.
But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion …
He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.