Darwin, Plato, and Aristotle
Chapter 8 endnote 27, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:
This illusory hierarchy [of the brain evolving in layers] embodied Darwin’s ideas about human evolution — base appetites having evolved first, followed by wild emotional passions, with rationality as our crowning glory. [...] Darwin’s ideas came from Plato and Aristotle.
Charles Darwin wrote in The Descent of Man and Selection in Relation to Sex:
"Man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system—with all these exalted powers—Man still bears in his bodily frame the indelible stamp of his lowly origin."[1]
With this brief phrase, Darwin signaled his belief that the human mind contained an “inner brute” that evolved from less advanced animals. These ideas crept into the writings of neurologist Paul Broca (of “Broca’s area” fame) who outlined what he believed to be an ancient limbic “lobe” for emotion located deep within the human brain, and of neurologist Paul MacLean of "triune brain" fame. But these ideas were not original to Darwin, and can be found as far back as Ancient Greece in the writings of Plato and Aristotle.
Plato (around 400 BCE) chopped the human psyche (mind and soul) into three parts: passions (which today we would call emotions) and appetites (like hunger and sex drive) that we share with other animals, and rational thoughts, which are in charge. Aristotle carved the psyche into five parts (shared some of them with other animals, including emotions, and even with plants). But one important theme stood out consistently. The human psyche was consistently elevated above all others because its faculty of rationality was uniquely human. The ability to think placed human beings at the pinnacle of all living things.[2] Aristotle also gave us the scala naturae — a “fish to human” progression presupposes (wrongly) that evolution is unrelentingly progressive, moving towards ever more sophisticated animal forms, with humans at the pinnacle.
Still, Darwin did not assume that apes and monkeys had no noble qualities. He wrote, "For my own part I would as soon be descended from that heroic little monkey, who braved his dreaded enemy in order to save the life of his keeper; or from that old baboon, who, descending from the mountains, carried away in triumph his young comrade from a crowd of astonished dogs—as from a savage who delights to torture his enemies, offers up bloody sacrifices, practices infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions." So much for Darwin "establishing the unity of mankind, challenging the racist assertions.