Rousseau’s Discourse on Inequality (1754), published by Marc-Michel Rey in 1755 in Holland.

Like other Enlightenment philosophers, Rousseau was critical of the Atlantic slave trade.[38]

Rousseau first exposes in this work his conception of a human state of nature, presented as a philosophical fiction (like by Thomas Hobbes, unlike by John Locke), and of human perfectibility, an early idea of progress. He then explains the way, according to him, people may have established civil society, which leads him to present private property as the original source and basis of all inequality.

Rousseau discusses two types of inequality: natural, or physical inequality, and ethical, or moral inequality. Natural inequality involves differences between one human’s body and that of another—it is a product of nature. Rousseau is not concerned with this type of inequality because he claims it is not the root of the inequality found in civil society. Instead, he argues moral inequality is unique to civil society and is evinced in differences in “wealth, nobility or rank, power and personal merit.”[3] This type of inequality is established by convention. Rousseau appears to take a cynical view of civil society, where man has strayed from his “natural state” of individual independence and freedom to satisfy his individual needs and desires.

His discussion begins with an analysis of a natural man who bears, along with some developed animal species, instincts for self-preservation—a non-destructive love of self (amour de soi meme)—and a “natural repugnance” to suffering—a natural pity or compassion. Natural man acts only for his own sake and avoids conflicts with other animals (and humans). Rousseau’s natural man is more or less like any other animal, with “self-preservation being his chief and almost sole concern” and “the only goods he recognizes in the universe” being “food, a female, and sleep…” Rousseau’s man is a “savage” man. He is a loner and self-sufficient. Any battle or skirmish was only to protect himself. The natural man was in prime condition, fast, and strong, capable of caring for himself. He killed only for his own self-preservation.

Natural man’s anthropological distinction (from the animal kingdom) is based on his capacity for “perfectibility” and innate sense of his freedom. The former, although translated as “perfectibility,” has nothing to do with a drive for perfection or excellence, which might confuse it with virtue ethics. Instead, perfectibility describes how humans can learn by observing others. Since human being lacks reason, this is not a discursive reasoning, but more akin to the neurological account of mirror neurons. Human freedom does not mean the capacity to choose, which would require reason, but instead the ability to refrain from instinct. Only with such a capacity can humans acquire new habits and practices.

The most important feature of Rousseau’s natural man is that he lacks reason, in contrast to most of the Western intellectual tradition. Rousseau claims natural man does not possess reason or language (in which reason’s generation is rooted) or society—and these three things are mutually-conditioning, such that none can come into being without the others.