1 - The adjustive or adaptive function. Schools are to establish fixed habits of reaction to authority. This, of course, precludes critical judgment completely. It also pretty much destroys the idea that useful or interesting material should be taught, because you can't test for reflexive obedience until you know whether you can make kids learn, and do, foolish and boring things.
2 - The integrating function. This might well be called "the conformity function," because its intention is to make children as alike as possible. People who conform are predictable, and this is of great use to those who wish to harness and manipulate a large labor force.
3 - The diagnostic and directive function. School is meant to determine each student's proper social role. This is done by logging evidence mathematically and anecdotally on cumulative records. As in "your permanent record." Yes, you do have one.
4 - The differentiating function. Once their social role has been "diagnosed," children are to be sorted by role and trained only so far as their destination in the social machine merits - and not one step further. So much for making kids their personal best.
5 - The selective function. This refers not to human choice at all but to Darwin's theory of natural selection as applied to what he called "the favored races." In short, the idea is to help things along by consciously attempting to improve the breeding stock. Schools are meant to tag the unfit - with poor grades, remedial placement, and other punishments - clearly enough that their peers will accept them as inferior and effectively bar them from the reproductive sweepstakes. That's what all those little humiliations from first grade onward were intended to do: wash the dirt down the drain.
6 - The propaedeutic function. The societal system implied by these rules will require an elite group of caretakers. To that end, a small fraction of the kids will quietly be taught how to manage this continuing project, how to watch over and control a population deliberately dumbed down and declawed in order that government might proceed unchallenged and corporations might never want for obedient labor.
Quoted from "Weapons of Mass Instruction" by John Taylor Gatto.
Read his earlier book "The Underground History of American Education" here.
Find Alexander Inglis's "Principles of Secondary Education" here.