You make many great points about impartiality, I see it as the most important aim for those who want to develop themselves in this life. We all learn from life daily, it's easy to see, even if it's only at the level of repetition of experience or maybe the discovery of a new experience that changes the established world view for the individual. I agree that we are born with a clean slate so to say that gets influenced by our educational experience from outer conditions interacting with what we are born with that creates a subjective individual experience that can have relative impartiality. That is it applies to that limited experience.
So it's a matter of scale even in an individual life. I can be impartial to these words for instance and stand apart from them internally or on the other hand I can get caught up in them and to hell with everything else including the ringing of the phone right next to me!
I see impartiality as a very big thing, a lofty goal to be aspired to, one that I can work on every day whenever I can remember and my efforts to remember are rewarded with an expanding world view that has less limits imposed on it by my own subjective viewpoint.
Thanks for a great post!