GALEN: On the Natural Faculties

Galen lived in the Roman Empire during the late 100s AD. He is primarily known for his contributions to medicine, especially for his refinement of the Hippocratic theory of the four humors.

HIPPOCRATES: The Oath; On Ancient Medicine; On Airs, Waters, and Places; The Book of Prognostics; Of the Epidemics; The Law; On the Sacred Disease

Hippocrates is known as the “Father of Medicine.” Although many of his medical claims have been proven false, his approach to medicine was revolutionary, and it has endured to the present day. He sought for the causes of disease in natural things, such as the weather, a person’s diet, and a person’s genetics. This is a radical departure from the previous belief that illness was a punishment sent from the gods.

ARISTOTLE: On the Soul [Book II, Ch. 1-3; Book III]

Aristotle claims that the soul is the form and essence of all living things. The soul is composed of many parts. All living things – plants and animals – possess a soul with a generative part, which is responsible for the nutrition and reproduction of living beings. Only animals possess a soul with a sensitive part, which enable the animal to feel pleasure and pain. Some animals possess other senses such as sight, smell, and taste. Finally, only man possess a soul with the ability to think.

ARISTOTLE: Categories

In the Categories, Aristotle develops a classification system to assign each object known to man under one of ten categories. “Of things said without any combination, each signifies either substance or quantity or qualification or a relative or where or when or being-in-a-position or having or doing or being-affected. To give a rough idea, examples of substance are man, horse; of quantity: four-foot, fivefoot; of qualification: white, grammatical; of a relative: double, half, larger; of where: in the Lyceum, in the market-place; of when: yesterday, last-year; of being-in-a-position: is-lying, is-sitting; of having: has-shoes-on, has-armour-on; of doing: cutting, burning; of being-affected: being-cut, being-burned.”