One of Kant's students reported that he often introduced his lectures by saying that he lectured neither for the very bright (Genies), because they would find their own way, nor for the stupid, because they were not worth the effort, but only for those in the middle, who were seeking to be educated for a future profession.
(Manfred Kuehn, Kant: A Biography [Cambridge: Cambridge University Press, 2001], 358-9 [endnote omitted])
Note from KBJ: I love this! In fact, it's how I've taught my own courses for the past 26 years (five at the University of Arizona, one at Texas A&M University, and 20 at the University of Texas at Arlington). I think of it as pedagogical triage.