He was a Greek medical writer and philosopher-scientist. He probably wrote his book sometime between 500 and 450 BC. The surviving fragments focused primarily on issues of psychology and epistemology. They reveal Alcmaeon to be a thinker of innovation. He was the first to identify the brain as the seat of understanding and to recognize understanding from perception. Alcmaeon thought that the sensory organs were connected to the brain by channels. He also discovered the optic nerve by excising the eyeball of an animal. He was the first to develop an argument for the immortality of the soul. He used a political metaphor to define health and disease. The political metaphor was "The equality of the opposing powers which make up the body (the wet, the dry, the hot, the cold, the sweet, the bitter etc.)preserve health, whereas the monarchy of any one of them produces disease." Aristotle wrote a treatise responding to him, Plato adopted his argument for the immortality of the soul, and both Plato and Philolaus accepted his view that the brain is the seat of intelligence.
Aristotle was born in 384 BCE. in Stagirus, Greek. He joined the Academy and studied under Plato. He spent twenty years of his life studying at the Academy. In 335 he came back to Athens and he established his own school. He spent most of the rest of his life there in research, teaching, and writing. The surviving works of Aristotle probably represent only a small piece of the whole thing, they include his investigations of logic, philosophy, and ethics to physics, biology, psychology, politics, and rhetoric. Aristotle goal was to develop a universal method of reasoning so it would be possible to learn everything there is to know about reality. .
Epicureans & Epicurus.
Epicurus was the founder of the Epicureans. He was born in Athens in about 342 B.C. The Epicureans, like the Stoics, distinguish valid only that knowledge which originates and stops in the senses.