Locke, Some Thoughts Concerning Education, section 149:
Thus Children may be cozen’d into a Knowledge of the Letters; be taught to read, without perceiving it to be any thing but a Sport, and play themselves into that which others are whipp’d for. Children should not have any thing like Work, or serious, laid on them; neither their Minds, nor Bodies will bear it. It injures their Healths; and their being forced and tied down to their Books in an Age at enmity with all such Restraint, has, I doubt not, been the Reason, why a great many have hated Books and Learning all their Lives after. ‘Tis like a Surfeit, that leaves an Aversion behind not to be removed.
I can only think that if more of my teachers post-Montessori School had embraced this 18th-century philosophy, I (and my peers) would have been a lot less miserable for much of our childhoods.