Early philosophers were divided as to whether the seat of the soul lies in the brain or heart. Aristotle favored <answer>the heart</answer>, and thought that the function of the brain was merely to cool the blood. Democritus, the inventor of the atomic theory of matter, argued for a three-part soul, with intellect in the head, emotion in <answer>the heart</answer>, and lust near the liver. Hippocrates, the "father of medicine", came down unequivocally in favor of the brain. In his treatise on epilepsy he wrote:
Aristotle thought the soul lied in what organ?
the heart