A Greek philosopher who lived in the 4th century BCE, Aristotle (384–322 BCE) was a student of Plato and became one of the most influential thinkers of all time. He was studied and admired by the greatest Jewish, Christian, and Islamic philosophers of the Middle Ages and was then known as “the Philosopher” and “the master of those who know.” His works are both profound and breathtakingly comprehensive. Among other subjects, they address natural science, psychology, logic, ethics, metaphysics, rhetoric, and the art of poetry. Aristotle’s corpus also includes works treating the analyses at the heart of this encyclopedia.

Along with its breadth, three general characteristics of his work help distinguish Aristotle from other ancient philosophers. He was greatly concerned with empirical evidence, so when studying ...