Perhaps the best answer to this question can be found in the book Émile, which was, essentially, a treatise on education. Rousseau begins by observing that "God makes all things good; man meddles with them and they become evil." He views education, then, as the source of a great deal of evil in the world, because, as it existed in eighteenth-century France, it was a corrupting influence. At the same time, he viewed a good education as essential—indeed, it was the only hope of creating a good society. As he said in another aphoristic statement later in the first chapter:

We are born weak, we need strength; helpless, we need aid; foolish, we need reason. All that we lack at birth, all that we need when we come to man’s estate, is the gift of education.

Rousseau argued that what was essential was that one's education conform to, and ultimately foster to, reason, which was the ultimate aim of education. For this radical philosopher, this meant allowing children to be free and to learn at their own pace and to focus on what we might call skills-based learning. In the eighteenth-century, this was a radical idea, because most education was didactic and emphasized the rote memorization of texts and facts. Rousseau saw this as unnatural. If people were to live as free men within a society, they had to learn to exercise reason. Rousseau also, in the most famous part of the book, advocated a highly gendered form of education for young women. Girls, he thought, should learn the things that were specific to their sphere—appreciation for the arts, socializing, and other aspects of a cultured young woman's world. Here, too, Rousseau argued that education should align with reason and nature, reinforcing the latter.

For Rousseau, the fundamental aim of education can be seen in his idea of how "Man is born free, but lives in chains."  Rousseau believes that any notion of human perfectability and success of education exists in keeping children away from the corrupting element of society.  Rousseau's theory of education is a pastoral one, driven by the need to keep children free from the "evil" elements of the urban sprawl:  “Men are devoured by our towns.”  For Rousseau, the basis of education is one in which a free love of knowledge for knowledge's sake is what drives comprehension and understanding:  “The natural man is interested in all new things."  This drive to uncover "the natural man" is one of the fundamental aims of Rousseau in his construction of education.  There is a reclamation that is a part of the learning and something that the teacher, namely him, must keep in mind as he seeks to illuminate this condition of being within the student.  

One of the aims of education has to be to ensure that this natural state is facilitated within the child, and that the sense of freedom within the individual is expanded:  “When our natural tendencies have not been interfered with by human prejudice and human institutions, the happiness alike of children and men consists in the enjoyment of their liberty.”  This drive back towards our "natural tendencies" becomes one of Rousseau's aims of education.