Aristotle
Aristotle lived from 384 to 322 BC. He was a Greek philosopher who was a student of Plato and the tutor of Alexander the Great. Aristotle emphasized reason and observation of the natural world, and he is believed by many to be the greatest philosopher of all time and the founder of empiricism, the ontological grounding of science.
Aristotle came to the Academy when he was seventeen and stayed there for twenty years until the death of Plato. Aristotle’s approach was in stark contrast to Plato's. Whereas Plato thought all true knowledge could be obtained a priori—a disembodied mind floating in a featureless void with no sense experience could work out everything there is to know—Aristotle thought that the natural world needed to be studied and observed for knowledge to be gained. He embarked on the massive task of observing and compiling as much information as possible on everything he could study at the time. In contrast to Plato’s interest in physics and maths, Aristotle was fascinated by biology, and classified over 500 animal species. He ultimately founded his own school, the Lyceum, and equipped it with specimens, libraries, maps and other objects found in modern university.
Charles Murray said, "He more or less invented logic, which was of pivotal importance in human history (and no other civilization ever came up with it independently)." [1]
Aristotle also formulated Virtue Ethics, a code of living which emphasizes what sort of person we want to be when making a decision, rather than, as tends to be the focus in modern ethical thinking, the motives or the consequences of actions (see Nicomachean Ethics). When Aristotle's teachings were brought back to Europe at the end of the Dark Ages by Arab merchants, Aquinas, eager to reconcile Catholicism with Aristotle's secular empiricism, developed Natural Law Theory.
Aristotle was not a theist and rejected the existence of the Old Gods many Athenians worshiped. However, he recognized the impossibility of an infinite regress of cause and effect in the natural world, and so postulated The Unmoved Mover as a First Cause of the natural world. Some argue this makes Aristotle the first recorded deist, though he did not predate certain movements in Egypt and the near East, and his Unmoved Mover can very effectively be understood as part of man's journey towards the God of Christ.
