Rousseau on human evolution: vindicated by modern science

This is the second post about my recently published book, "Rousseau's Rejuvenation of Political Philosophy: A New Introduction (Palgrave Macmillan, 2016)."

The deepest root of Jean-Jacques Rousseau's opposition to Enlightenment political thought can be traced to his views on the state of nature, which are set out most openly in his "Discourse on Inequality." For modern social contract thinkers like Thomas Hobbes and John Locke, the state of nature is the condition in which people like us find themselves before governments are instituted or where they have stopped operating. Rousseau believed this was extremely misleading because it assumes that what we are now we are by nature.

For Rousseau, the nature of man is not an observable phenomenon. Instead, it is something that lies hidden beneath layers of characteristics acquired through our social lives, including the most important of all social institutions, human speech. The true state of nature is the condition men were in before being shaped by social life into the strange and unique animal that we are.

A century before Charles Darwin, Rousseau recognized that physical evolution must have occurred during the history of our species. He also recognized that no one yet had sufficient data from comparative anatomy and the observations of naturalists to allow solid reasoning about what we call speciation. Accordingly, he provisionally assumes that humans have always been animals whose bodies looked the way we look today.

He is nonetheless completely confident that the souls of our ancestors were very different from ours. Lacking speech - i.e., compositional languages in which a limited number of symbols, used according to grammatical rules, enable us to generate an unlimited number of expressions of unlimited complexity - our distant ancestors could not have been fundamentally different from other animals.

The state of nature, according to Rousseau, no longer exists, and it cannot be recovered. It was an articulated period of time during which changes in the physical environment pushed our forebears to adapt by cooperating with one another more than they had in the past. Rousseau presents a frankly conjectural account of the stages through which mankind probably passed.

In the first stage, he imagines that adults lived largely in solitude except for females who cared for their children until they were able to take care of themselves. Eventually, males and females began to live together and share the care of children. When a number of these families began to interact on a regular basis, tribes were formed in which life maintained a fair mean between the indolent solitude of the primitive state and the petulant activity of civilized man's amour propre. This was the last stage of the state of nature, and Rousseau regarded it as "the happiest epoch and the most durable." The state of nature ended when a right of property in land was recognized.

Rousseau was apparently the first to suggest that humans developed from ape origins, which is remarkable when one considers how little information he had even about the extant apes. Life in each of Rousseau's stages of evolution corresponds remarkably well with the life of a great ape that has only recently been carefully studied: Orangutans live much like Rousseau's earliest humans, gorillas live in isolated patriarchal family groups, and chimpanzees are cooperative and contentious hunter-gatherers like people in Rousseau's last stage of the state of nature. This suggests that our fundamental ape nature lent itself to all these possibilities.

Modern science has concluded that we are descended from an arboreal ape that lived in African rainforests before environmental changes forced their kind to adapt to a colder and dryer environment. Scientists know nothing about the lives of those extinct animals, who might have lived like the orangutans found in tropical rainforests today. Even if the common ancestor that we share with the great apes in fact lived more like gorillas or chimpanzees, Rousseau's main point stands: We have ancestors who lacked the distinctive human institution of compositional language, and thus were not truly human.

There is a great deal that scientists do not know about the lives of our early forebears, but they have learned something from the fossil record and genetic analysis, and some inferences can be drawn from the behavior of other primates. With respect to the origin of the most important distinguishing human characteristic, namely speech, almost nothing at all is known.

Suggestive evidence has been found, and scientists have offered a variety of speculative theories, but none of those theories has been scientifically confirmed. In the "Essay on the Origin of Languages," Rousseau offers his own speculative account, which turns out to be quite consistent with the limited evidence we now have.

Rousseau saw in Plato's "Cratylus" a recognition that human language always incorporates questionable assumptions, some of which originate from human passions. He then undertakes an investigation of the interrelationships between passions and intellectual enlightenment in the genesis of languages, an investigation that is meant as a serious version of the ironic speculations about etymologies in the "Cratylus."

Very briefly stated, Rousseau argues that verse, songs and speech had a common origin and were initially indistinguishable. Conventional languages originated from a prelinguistic need or desire to communicate, persuade and form bonds in relatively small groups. As language was increasingly adapted to the communication of complex ideas, a separation of music and speech gradually arose.

There are natural limits on how well language can serve its original functions of persuading and bonding while becoming less musical, and Rousseau believed that European languages have lost much of their ability to serve those functions.

Rousseau did not believe that we can return to the healthy freedom of what he called "the happiest epoch, and the most durable," or that this tribal life was without its inherent tensions. Nor did he imagine that we can reconstitute languages containing the optimal blend of intellectual sophistication and musicality (an example of which he saw in Homer). What he does maintain is that understanding where we came from and how we got here can help us to be guided by nature in dealing with our current situation. The remainder of my book begins to explore Rousseau's efforts to set forth that guidance.

[Nelson Lund has been guest-blogging this week; parts of these posts are borrowed from his book.]