There seems to be a balancing act here -- just thinking a bit more about my last post. David Hicks writes about a "prescriptive" norm. Many modern educationalists will be in tune with the "descriptive" norm.... ie, what is a normal 1st grader capable of, then trying to get the child to meet that standard. The "prescriptive" teacher will have an ideal of perfection in mind, and then..... what? I'm not in tune enough with past times to know. The conventional modern-day tendency is to think that education then became punitive and unrealistic. Expecting a small child to do things he is developmentally incapable of, by means of threats and humiliation and beating. In ideal, theoretical terms I would imagine that a prescriptive ideal of "perfection" could induce humility in ALL the participants, even the teacher who recognized his own short-comings.
Anyway, I suppose ideally there would be a balance. One would have a prescriptive goal but use lots of descriptive common sense in reaching that goal. I see that with Kolbe Academy's approach at its best. Having a prescriptive ideal often brings out sins of the spirit -- impatience, wrath, discouragement. But setting sights lower may induce other sins -- sloth, laxity, indifference. It is truly a balancing act.