Democritus
460-370 BC
Democritus, a Greek physician, was a contemporary of Hippocrates and Plato. He proposed that matter was made up minute units called “atoms.” Atoms, he said, differed in shape depending upon how they functioned. Round atoms made up fluids, irregular atoms made up solids. Differently shaped atoms also lead to different tastes, with hooked atoms resulting in acid tastes and large round atoms resulting in sweet tastes.
Democritus, along with Plato, divided the soul into three parts. One part was located in the head and was associated with intellect, a second was in the heart and associated with high level feelings such as anger, fear and pride, and a third was located in the liver where it promoted lower level passions such as lust, greed, and desire. When an individual died, Democritus believed, all three parts of his soul died with him (from Finger, 1994, p. 14).
Finger, S. (1994). Origins of neuroscience: A history of explorations of the brain function. NY: Oxford University Press.