A huge (the primary?) purpose of the educational system is not to teach people how to do things, but rather to rate and rank them for comparison. As an instruct

A huge (the primary?) purpose of the educational system is not to teach people how to do things, but rather to rate and rank them for comparison. As an instructor there's always a conflict, you want to provide an accurate ranking of ability/knowledge/etc in the subject in the form of grades but you also want to push the students to learn and do interesting work, unfortunately it's impossible to do the first with groups, and often it's impossible to do the second without them.