Rousseau (1712-78), though he paid his respects to Plato's philosophy, rejected it as impractical due to the decayed state of society. Rousseau also had a different theory of human development--where Plato held that people are born with skills appropriate to different castes (though he did not regard these skills as being inherited), Rousseau held that there was one developmental process common to all humans. This was an intrinsic, natural process, of which the primary behavioral manifestation was curiosity. This differed from Locke's tabula rasa in that it was an active process deriving from the child's nature, which drove the child to learn and adapt to its surroundings.
As Rousseau wrote in his book Emile, all children are perfectly designed organisms, ready to learn from their surroundings so as to grow into virtuous adults. But, due to the malign influence of corrupt society, they often fail to do so. Rousseau advocated an educational method which consisted of removing the child from society (i.e., to a country home) and alternately conditioning him through changes to environment and setting traps and puzzles for him to solve or overcome.
Rousseau was unusual in that he recognized and addressed the potential of a problem of legitimation for teaching. He advocated that adults always be truthful with children, and in particular that they never hide the fact that the basis for their authority in teaching was purely one of physical coercion--"I'm bigger than you." Once children reached the age of reason (about 12), they would be engaged as free individuals in the ongoing process of their own.