The natural philosophy of Aristotle. Book IX: The eternal character of movement. Refutation of contrary arguments. The first unmoved mover. Unique and eternal character of the first mover. Direction as the first kind of movement. The only continuous and infinite movement is circular. The first mover has no parts or size and is located at the circumference of the world.

Aristotle, son of the physician Nicomachus, was born in Stagira in 384 B.C. Information about his early years is minimal. At the age of seventeen, he went to Athens to study at the Platonic Academy. He stayed there for twenty years, from 367 to 348 B.C., when Plato died. Then Aristotle left for Assos in Troas and after a three-year stay there, he went to Lesbos and then to Macedonia, where he took on the education of the royal child Alexander.

When his student ascended the throne, Aristotle settled in Athens and founded his school, the Lyceum. After Alexander's death (323 B.C.), the philosopher's stay in Athens became difficult. He was forced to take refuge in Chalcis, his mother’s homeland, where he died in 322.

A universal mind, Aristotle created a vast and valuable philosophical and scientific work. Epistemology, logic, theology, physics, biology, psychology, ethics, political philosophy, aesthetics are the main fields of knowledge that he investigated and studied. The Alexandrian Hermippus counted Aristotle's works to be 400. To this day, lists have survived that include 143 titles of his works. Diogenes Laertius estimated the number of verses of Aristotle's writings to be 440,000. The influence of his work on the formation of global thought was strong for centuries and remains so.

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