We can all see how obvious other-peoples' assumption are - and how these are completely resistant to emerging evidence.
(Such is a property of all assumptions: they are prior-to and "above" all possible evidence; because assumptions select and interpret all evidence.)
This is particularly evident when it comes to large scale and abstract matters. For instance, geopolitical assumptions are indestructible, even across generations - especially when the assumptions are negative: as when it comes to be assumed that a particular nation (or national leader) is hostile, a threat, evil.
Similar assumptions govern attitudes between some races - and these need not be symmetrical (i.e. one race may regard another as intrinsically hostile, but that feeling may not be reciprocated).
Of course there is also an element of the self-fulfilling prophecy at work; but even without anything of that kind, such assumptions cannot be overthrown by experience.
Yet, although evidence-immune, assumptions may be abandoned and replaced.
And assumptions must be adopted in the first place - even when they are unconsciously socially inculcated.
So - given that factual information is irrelevant - is there any valid basis by which particular assumptions ought to be adopted or abandoned?
My answer would be several layered.
First and most important is awareness...
As of here-and-now; assumptions ought to be (or become) conscious, and we ought to be aware that they are prior to evidence (because assumptions structure our choice and understanding of evidence).
So we should not assert that our assumptions are obvious or inevitable; and should not suppose that our assumptions derive from factual evidence.
Such a recommendation of what not to do, is easier said than done! I break it habitually, several times a day - yet in doing so I am making an error - with many ill consequences.
But I still have not said anything about choosing between assumptions?
The answer, as with all ultimate matters, is always a matter of intuition - which we cannot go beneath; but which we can recognize and acknowledge as the reality behind our engagement with the world.
I think it could be said that (assuming we desire to be coherent) our assumptions need to fit our deepest and most solid intuitions. So, for a Christian, all further assumptions need to fit with that ultimate intuition (including the ultimate intuitions of what "being a Christian" actually means).
Once we have identified our our assumptions; we should then choose whether we really do wish to retain them as assumptions - or else replace them with others - as we are free to do!
It is a matter of admitting this necessary freedom as our own active choice, and of taking responsibility for its exercise.
