Aristotle (384–322 BCE) was one of the most important western philosophers in history. A student of Plato, Aristotle tutored Alexander the Great. He later went on to form his own Lyceum (school) in Athens, where he developed important philosophical, scientific, and practical theories, many of which had great significance during the Middle Ages and are still influential today. Aristotle wrote on logic, nature, psychology, ethics, politics, and art, developed one of the first systems for classifying plants and animals, and posited significant theories on topics ranging from the physics of motion to the qualities of the soul. He is credited with developing deductive ("top-down") reasoning, a form of logic used in the scientific process and highly valued in business, finance, and other modern settings.

Fast Facts: Aristotle

Known For: One of the greatest and most influential philosophers of all time, as well as a tremendously important figure in the history of science, mathematics, and theater

Born: 384 BCE in Stagira, Greece

Parents: Nichomachus (mother unknown)

Died: 322 BCE in Chalcis, on the island of Euboea

Education: Academy of Plato

Published Works: Over 200 works, including Nichomachean Ethics, Politics, Metaphysics, Poetics, and Prior Analytics

Spouse(s): Pythias, Herpyllis of Stagira (mistress with whom he had a son)

Children: Nicomachus

Notable Quote: "Excellence is never an accident. It is always the result of high intention, sincere effort, and intelligent execution; it represents the wise choice of many alternatives – choice, not chance, determines your destiny."

Early Life

Aristotle was born in 384 BCE in the city of Stagira in Macedonia, a seaport on the Thracian coast. His father Nichomacus was the personal physician to King Amyntas of Macedonia. Nichomacus died while Aristotle was still young, so he came under the guardianship of Proxenus. It was Proxenus who sent Aristotle, at age 17, to complete his education in Athens.

Upon arriving in Athens, Aristotle attended the institution of philosophical learning known as the Academy, which was founded by Socrates' pupil Plato, where he stayed until Plato's death in 347. Aristotle was an outstanding pupil and soon began giving his own lectures on rhetoric. Despite his impressive reputation, however, Aristotle often disagreed with Plato's ideas; the result was that, when a successor to Plato was selected, Aristotle was passed over in favor of Plato's nephew Speusippus.

With no future at the Academy, Aristotle was not at loose ends for long. Hermeas, ruler of Atarneus and Assos in Mysia, issued an invitation for Aristotle to join his court. Aristotle remained in Mysia for three years, during which he married the king's niece Pythias. At the end of the three years, Hermeas was attacked by the Persians, leading Aristotle to leave the country and head to the island of Lesbos.

Aristotle and Alexander the Great

In 343 BCE, Aristotle received a request from King Phillip II of Macedonia to tutor his son Alexander. Aristotle agreed to the request, spending seven years working closely with the young man who would later become the famous Alexander the Great. At the end of seven years, Alexander was crowned king and Aristotle's work was complete. Though he left Macedonia, however, Aristotle stayed in close touch with the young king, corresponding regularly; it is likely that Aristotle's counsel had a significant impact on Alexander for many years, inspiring his love of literature and the arts.

The Lyceum and Peripatetic Philosophy

Leaving Macedonia, Aristotle returned to Athens where he set up The Lyceum, a school that became a rival to Plato's Academy. Unlike Plato, Aristotle taught that it is possible to determine the end causes and purposes of existence and that it is possible to figure out these causes and purposes through observation. This philosophical approach, called teleology, became one of the major philosophical concepts of the western world.

Aristotle divided his study of philosophy into three groups: practical, theoretical, and productive sciences. Practical philosophy included the study of fields such as biology, mathematics, and physics. Theoretical philosophy included metaphysics and the study of the soul. Productive philosophy focused on crafts, agriculture, and the arts.

During his lectures, Aristotle would constantly walk back and forth around the Lyceum's exercise grounds. This habit became the inspiration for the term "peripatetic philosophy," meaning "walking around philosophy." It was during this period that Aristotle wrote many of his most important works, which had profound impacts on later philosophical thinking. At the same time, he and his students conducted scientific and philosophical research and amassed a significant library. Aristotle continued to lecture at the Lyceum for 12 years, finally selecting a favorite student, Theophrastus, to succeed him.

Death

In 323 BCE when Alexander the Great died, the Assembly in Athens declared war against Alexander's successor, Antiphon. Aristotle was considered an anti-Athenian, pro-Macedonian, and so he was charged with impiety. Bearing in mind the fate of Socrates, who was unjustly put to death, Aristotle went into voluntary exile to Chalcis, where he died one year later of a digestive ailment in 322 BCE at the age of 63.

Legacy

Aristotle's philosophy, logic, science, metaphysics, ethics, politics, and system of deductive reasoning have been of inestimable importance to philosophy, science, and even business. His theories impacted the medieval church and continue to have significance today. Among his vast discoveries and creations are included:

• The disciplines of "natural philosophy" (natural history) and metaphysics
• Some of the concepts that underlie Newtonian laws of motion
• Some of the first classifications of living things based on logical categories (the Scala Naturae)
• Influential theories about ethics, war, and economics
• Significant and influential theories and ideas about rhetoric, poetry, and theater

Aristotle's syllogism is at the basis of deductive ("top-down") reasoning, arguably the most common form of reasoning used today. A textbook example of a syllogism is:

• Major premise: All humans are mortal.
• Minor premise: Socrates is a human.
• Conclusion: Socrates is mortal.