Aristotle was born at a time when Greek learning was at its height, and perhaps he himself was the culmination. There were important scientists, mathematicians, and thinkers before and after him, but the two greatest intellectuals produced by the Greek civilization were Plato and Aristotle. Plato was about forty- five years older than Aristotle, and thus Plato served as Aristotle's mentor. But, by the time Aristotle entered the Academy at the age of eighteen, it was no longer a thriving place full of youthful enthusiasm. Works such as the Republic, Phaedo, and the Symposium had already reached the status of revered classics, though they were not above criticism. The Academy was still the center for learning, of course, but the Socratic spirit had died down. This shift was reflected in Plato's later dialogues, which consisted of much more exposition than genuine exchange.
Nevertheless, the Academy had a profound influence on Aristotle's development, and although he departed from his master's thought significantly, many of the Academy's fundamental principles still served as the foundation of his work. Aristotle had a great deal to build on and to respond to, particularly in Plato's metaphysics and politics. For example, he would come to disagree with Plato's Theory of Forms, which he saw as empty idealism that served no purpose for the material world. His own politics again built on the fundamental principles of Plato, as he concurred with certain principles of the ruling aristocracy but devised his own vision of the ideal state. In other areas he had very little precedent from which to work. He virtually invented the field of logic, and he reinvented the previously insignificant field of biology. While this was going on, he inevitably distanced himself from the Academy, whose focus had become more mathematical.
Politically, Athens had ceased to be the great power of Greece, though it remained a cultural center. Macedonia had risen under the leadership of Philip II, and after him Alexander would conquer the Persian Empire and unite the reluctant Greek states under his power. Aristotle himself was a resident alien in Athens, and his affiliation with Macedonia–through his father's position as court physician and his tutorship of Alexander–put him in an uneasy position. Twice he would have to leave for his own safety. The first time was after Plato's death, when Philip and Macedonia began to show signs of aggression, and the second was after Alexander's death, when the Macedonian empire was bound to be dismantled.
The spirit of the Athenian city-state played a large role in Aristotle's political thought. He saw political participation as essential for individual fulfillment, and this relationship between man and community served as the fundamental principle behind his Politics. Whether Aristotle could have thrived in any other environment has never been seriously considered, for his work is so closely tied to his time and place. In writing his Poetics, he had a wealth of Greek literature to examine, including works that still remain a part of the Western canon. Aristotle's influence on the development of Western thought was far from an individual achievement, but it would not be unfair to say that he stands above any other single figure as the embodiment of Western learning.