How does Rousseau challenge the idea of human beings as essentially rational or of human psychology as ruled by intellect?

In his essay, "What is the origin of inequality among men and is it authorized by the natural law?", Rousseau applied his view of the development of individuals to the development of society itself. It was entered in a competition held by the Dijon Academy of Arts and Sciences in 1754. Four years earlier he had won the competition with another essay but this one, though more popular in years to come, won no award.

Rousseau's position on the development of the individual was a very naturalistic one. He proposed that a person is born a "noble savage", and that he will develop into what he is intended to regardless of outside influences. Though others have an effect on the individual, the actual person he or she becomes is "hard-wired" in their genetic makeup.

Since, according to Rousseau, this is true of the individual, it must also be true of the societies that are composed by these individuals. The greater is simply a reflection of the smaller. If one is "hard-wired", how can the other not be? If nature intends it, it must be inevitable.

This being the case it would seem that man is not ruled as much by intellect as one would normally assume, but that "nature" and its influences determine more than we realize.

In order to balance this position you might want to compare this position with that of John Locke and his "blank slate" view of development.