to speak [the truth]" Heraclitus' thought on logos influenced the Stoics, who referred to him to support their belief that rational law governs the universe. Pythagoreanism Pythagoras (582–496 BCE) was born on Samos, a small island near Miletus. He moved to Croton at about age 30, where he established his school and acquired political influence. Some decades later he had to flee Croton and relocate to Metapontum. Pythagoras was famous for studying numbers and the geometrical relations of numbers. A large following of Pythagoreans adopted and extended his doctrine. They advanced his ideas, reaching the claim that everything consists of numbers, the universe is made by numbers and everything is a reflection of analogies and geometrical relations. Numbers, music and philosophy, all interlinked, could comfort the beauty-seeking human soul and hence Pythagoreans espoused the study of mathematics. Pythagorianism perceived the world as perfect harmony, dependent on number, and aimed at inducing humankind likewise to lead a harmonious life, including ritual and dietary recommendations. Their way of life was ascetic, restraining themselves from various pleasures and food. They were vegetarians and placed enormous value on friendship. Pythagoras politically was an advocate of a form of aristocracy, a position which later Pythagoreans rejected, but generally, they were reactionary and notably repressed women. Other pre-Socratic philosophers mocked Pythagoras for his belief in reincarnation. Notable Pythagorians included Philolaus (470-380 BCE), Alcmaeon of Croton, Archytas (428-347 BCE) and Echphantus. The most notable was Alcmaeon, a medical and philosophical writer. Alcmaeon noticed that most organs in the body come in pairs and suggested that human health depends on harmony between opposites (hot/cold, dry/wet), and illness is due to an imbalance of them. He was the first to think of the brain as the center of senses and thinking. Philolaus advanced cosmology through his discovery of heliocentricism – the idea that the Sun lies in the middle of the earth's orbit and other planets. Pythagoreanism influenced later Christian currents as Neoplatonism, and its pedagogical methods were adapted by Plato. Furthermore, there seems to be a continuity in some aspects of Plato's philosophy. As Prof. Carl Huffman notes, Plato had a tendency to invoke mathematics in explaining natural phenomena, and he also believed in the immortality, even divinity of the human soul. The Eleatics: Parmenides, Zeno and Melissus The Eleatic school is named after Elea, an ancient Greek town on the southern Italian Peninsula. Parmenides is considered the