Aristotle

Aristotle (384 or 383 BC-322 BC) was a Greek philosopher and polymath born in Stagira, on the Chalcidice peninsula. Together with Plato, he is usually regarded as one of the fathers of Western philosophy. He founded the Peripatetic school at the Lyceum in Athens, and his writings cover logic, physics, biology, ethics, politics, rhetoric and poetics. His influence lasted for more than two thousand years and helped lay the groundwork for the modern scientific method.

Little is known about his life, and ancient biographies mix facts with speculation. His father, Nicomachus, was a physician to King Amyntas III of Macedon, which brought the family close to the royal court. Aristotle lost both parents while still young and was brought up by a guardian, Proxenus. At around seventeen or eighteen he went to Athens and joined Plato's Academy, where he stayed for about twenty years. He was said to have earned Plato's nickname "the reader" for his fondness for books.

After Plato's death, around 347 BC, he left Athens, probably because of the succession at the Academy and the anti-Macedonian feeling in the city. He lived in Assos and later in Mytilene on Lesbos, where he worked with Theophrastus on zoology and marine biology. In 343 BC Philip II invited him to Pella to tutor his son Alexander. He returned to Athens around 335 BC, founded his school in the Lyceum and built up a library. He spent roughly twelve years there, and during this period he composed much of his surviving work.

About thirty-one of his works survive in the Aristotelian corpus. Most were written as teaching materials rather than for publication. They include the Metaphysics, Physics, Nicomachean Ethics, Politics, On the Soul and Poetics. His logical writings, gathered as the Organon, contain the earliest systematic study of the syllogism.

His thought begins with experience. Unlike Plato, he held that forms do not exist apart from things but within them. In his hylomorphic theory, every substance is a compound of matter and form, and the form is its essence. He also explained change and purpose: everything in nature tends toward an end determined by its own nature. In ethics he proposed that human good, eudaimonia, consists in the exercise of reason, and that virtues are a mean between two extremes. For him, human beings are political animals who live by nature in the polis.

His final years in Athens were difficult. After Alexander's death in 323 BC, anti-Macedonian feeling grew, and he was charged with impiety. He withdrew to his mother's estate at Chalcis, on Euboea, and died there the following year. According to tradition, he said he would not let the Athenians sin twice against philosophy, a reference to the condemnation of Socrates.

His influence was vast. In the medieval Islamic world he was called "The First Teacher", and in Christian scholasticism, through Thomas Aquinas, simply "The Philosopher". His logic remained dominant until the nineteenth century, and his ethics of virtue regained attention in modern philosophy.