The Ecology of Humans (12) History


7,000 years ago, surgeons bore holes in patients’ skulls to cure afflictions. The exact purpose – whether to treat chronic headaches or mental illness or provide an easy escape route for evil spirits – remains a mystery. Some patients underwent multiple operations.

5,000 years ago, ancient Egyptians wrote about different symptoms of brain damage. But the heart was considered the seat of the soul, the keeper of memories.

Egyptian practice – for those wealthy enough – was to carefully preserve a body for the afterlife. Part of this process involved scooping the brain out through the nostrils and discarding it; no need for this skull stuffing any longer.

2,500 years ago, observant Greeks correlated structure to function. Body parts differ to perform different functions: the feet for walking, the hands for grasping, the head, with eyes, ears and mouth, specialized for sensing the environment. Dissection showed nerve tissue pathways to the brain, which must be the organ of sensation. Greek physician Hippocrates (460–379 bce), father of Western medicine, opined that the brain was not only a sensation organ, but also the seat of intelligence.

Aristotle (384–322 bce) clung to the notion that the heart was home to the intellect, while the brain acted as a radiator, to cool overheated blood. Aristotle thought that human capacity for rationality could be explained by the large cooling capacity offered by a big brain.