Aristotle

Aristotle arguably initiated the study of ethics with his examination of philosophical questions raised earlier by Socrates and Plato. In defining ethos, or character, Aristotle focused on individuals who possessed well-chosen habits of behavior that led to wellbeing and happiness. Deception, which adversely affects one's relationship with the surrounding world, interferes with the development of the habits required to achieve good and avoid evil. Aristotle greatly influenced Thomas Aquinas, a philosopher and theologian who is considered highly influential in the thought of the Catholic Church.

Aristotle was born in 384 b.c.e. on the Chal-cidic peninsula of Macedonia. In or about 367, Aristotle joined the Academy of Plato in Athens, where he served as Plato's student and colleague. After Plato's death in 348, Aristotle left Athens, moving first to the northwestern coast of Anatolia, and later the island of Lesbos. Aristotle was involved in extensive scientific research, and he is considered a pioneer in the fields of zoology and marine biology. In 343, Aristotle was asked to serve as tutor to the 13-year-old son of Philip II of Macedonia, the future Alexander the Great. In 334, Aristotle returned to Athens, founding a school known as the Lyceum just beyond the city's boundaries.

At the Lyceum, Aristotle assembled a large library and continued his work, which built upon rather than repudiated that of his mentor Plato. Unlike the Academy of Plato, which served as a private club, the Lyceum made many of its lectures open to the public without charge. During this period of stewardship of the Lyceum, Aristotle wrote the majority of his surviving works, exploring ethics, metaphysics, physics, politics, and psychology. Although Aristotle's relationship with Alexander had considerably cooled over the years, upon Alexander's death in 323, Aristotle left Athens, because his Macedonian background caused many of the citizens there to be suspicious of his motives. Aristotle escaped to Chalcis, and died the following year.