Euclid of MegaraEuclid of Megara (ˈjuːklɪd; Εὐκλείδης ; c. 435 – c. 365 BC) was a Greek Socratic philosopher who founded the Megarian school of philosophy. He was a pupil of Socrates in the late 5th century BC, and was present at his death. He held the supreme good to be one, eternal and unchangeable, and denied the existence of anything contrary to the good. Editors and translators in the Middle Ages often confused him with Euclid of Alexandria when discussing the latter's Elements. Euclid was born in Megara.
ProdicusProdicus of Ceos (ˈproʊdɪkəs; Πρόδικος ὁ Κεῖος, Pródikos ho Keios; c. 465 BC – c. 395 BC) was a Greek philosopher, and part of the first generation of Sophists. He came to Athens as ambassador from Ceos, and became known as a speaker and a teacher. Plato treats him with greater respect than the other sophists, and in several of the Platonic dialogues Socrates appears as the friend of Prodicus. One writer claims Socrates used his method of instruction. Prodicus made linguistics and ethics prominent in his curriculum.
Alcmaeon of CrotonAlcmaeon of Croton (ælkˈmiːɒn; Ἀλκμαίων ὁ Κροτωνιάτης, Alkmaiōn, gen.: Ἀλκμαίωνος; fl. 5th century BC) was an early Greek medical writer and philosopher-scientist. He has been described as one of the most eminent natural philosophers and medical theorists of antiquity and he has also been referred to as "a thinker of considerable originality and one of the greatest philosophers, naturalists, and neuroscientists of all time." His work in biology has been described as remarkable, and his originality made him likely a pioneer.
Eternity of the worldThe eternity of the world is the question of whether the world has a beginning in time or has existed from eternity. It was a concern for both ancient philosophers and the medieval theologians and medieval philosophers of the 13th century. The problem became a focus of a dispute in the 13th century, when some of the works of Aristotle, who believed in the eternity of the world, were rediscovered in the Latin West. This view conflicted with the view of the Catholic Church that the world had a beginning in time.
HippiasHippias of Elis (ˈhɪpiəs; Ἱππίας ὁ Ἠλεῖος; late 5th century BC) was a Greek sophist, and a contemporary of Socrates. With an assurance characteristic of the later sophists, he claimed to be regarded as an authority on all subjects, and lectured on poetry, grammar, history, politics, mathematics, and much else. Most of our knowledge of him is derived from Plato, who characterizes him as vain and arrogant. Hippias was born at Elis in the mid 5th-century BC (c. 460 BC) and was thus a younger contemporary of Protagoras and Socrates.
