The purpose of education is to create a good citizen. Rousseau believed that people are corrupted by society, that they cannot become good citizens because they are always striving to attain their individual desires. He envisioned an education that would teach people to put the "general will" of society, the good of society, before their own wills. Children are different from adults. Unlike the general view of the day, Rousseau did not see children as miniature adults. Rather, he saw children as innocent, vulnerable, slow to mature, and entitled to happiness. This perspective allowed a greater possibility that children could learn to become good citizens AND retain their self-esteem.
People develop through stages. Rousseau believed that different forms of education are appropriate for different stages of development. He is considered to be the first "developmentalist."

Stage 1Infancy (birth to two years).

Rousseau believed that the child learns the difference between power and liberty during this time. The responses of the adult reinforce the difference between want and need. The child learns to rely on himself, not others. That is, he learns the true liberty of self-sufficiency but not power over others. The focus is on allowing the child to be what he is — to nurse, to explore with the body, to be free of conflicting messages from adults. Stage 2The Age of Nature (two to 12). The child receives a "negative" education. He receives no moral education, no verbal learning. The idea is to "waste time" until the child’s "natural faculties" have developed. The purpose of this stage is to develop the physical qualities, particularly the senses. The mind is not addressed because it is not "ready." During this time, the child learns through his experiences not to want what he does not need; thus he become "free." He also learns natural consequences when his actions are not supported by "nature." This is part of learning not to want what is not needed. The teacher’s role is to shape the environment so that the necessary lessons are learned without pitting adult authority against the child’s desires.
Stage 3 — Pre-adolescence (12-15). At this stage Rousseau envisioned Emile as a "noble savage." He suggested that physical strength increases more rapidly than "needs" so that, naturally, a boy’s urge for activity takes a mental form. However, the only book Emile is allowed to read is Robinson Crusoe. This book reflects Emile’s own experiences in nature. It also provides a model for the solitary, self-sufficient man that Rousseau wanted Emile to become. In addition, the book does not present Emile with information that will cause him to want what he does not need or cannot have. Thus, he retains self-love without needing the approval of others. Rousseau saw the need of others’ approval as a corrupting influence. Stage 4Puberty (15-20). Rousseau believed that by this time, a boy’s reason or mental faculties would be well developed so that he could deal with the dangerous emotions of adolescence and with moral issues and religion. However, his idea was to introduce Emile slowly into society’s pressures. Book IV of The Emile, describes how to attend to moral development. Stage 5 — Adulthood (20-25). At this point, Rousseau believed the properly educated man should be introduced to his ideal partner and allowed to enter society. Given his prior preparation, the man should be able to resist the corrupting influences of society and participate effectively by willingly subjugating his own will to the general will.
The decision of what should be learned and taught is dependent on people’s "nature" at each stage. To Rousseau, the inclinations and faculties we have, before we are affected by people, and the faculties that develop without the intervention of people, are what constitute "nature." Rousseau believed that different faculties develop at different ages.

We are born capable of sensation and from birth are affected in diverse ways by the objects around us. As soon as we become conscious of our sensations, we are inclined to seek or avoid the objects which produce them . . . These inclinations (to seek or avoid) extend and strength the growth of sensibility and intelligence, but under the pressure of habit they are changed to some extent with our opinions. The inclinations before this change are what I call our nature. In my view everything ought to be in conformity with these original inclinations. (Emile, Book 1, 1956)

Education should be individualized because people vary within the stages. However, what is individualized is the teacher’s manipulation of the environment toward the desired end: creating a self-sufficient man capable of participating in society for the good of society, but who does so because he understands the difference between wants and needs, and because he does not want what he does not need. Every child has an impulse toward activity. Rousseau believed that mental activity is a direct result or development of bodily activity. The more able the teacher is to control the environment, the more effective the education of the child. Rousseau did not espouse letting a child grow without adult mediation. Rather, he believed that if the adult understood how the environment can help the child learn to "want only what he needs", the adult could shape the environment to teach that lesson without restricting the "freedom" of the child. Instead, the child would learn that true freedom means not wanting what you do not need. Men and women should be educated differently because their natures are different. Women were to be educated as complements to men. Women = weak and passive. Men = strong and active. Men should have power and will and women should not resist. Emile’s ideal mate was Sophie. She was educated in physical training for grace, dressing dolls to lead to drawing, writing, counting, reading, and the prevention of idleness and stubbornness. After the age of 10, her education was to focus on the arts of pleasing, religion, and the training of reason.