There is a very famous line of succession that included the three greatest ancient Greek philosophers: Socrates taught Plato, and Plato taught Aristotle, and the three of them together are responsible for the birth of Western philosophy as we know it. The whole line of succession occurred between 470 B.C. (Socrates year of birth) and 322 B.C. (Aristotle's year of death).
Although a student of Plato, Aristotle differed on many points with his great teacher. Whereas Plato was a rationalist, who believed that what we see is an imperfect copy of the intelligible Forms, Aristotle thought that what we know of the world must begin with the senses (empiricism). Thus, Aristotle set the stage for what would eventually develop into the scientific method, centuries later. His writings are eclectic and often dense, and include Physics, Metaphysics, Poetics, ethics, De Anima (On the Soul), and many many others.
Aristotle was interested in comparisons of actual governments, and began a project with his students of studying the constitutions of the Greek cities. Little of this material survives. He was also the tutor of Alexander of Macedon, otherwise known as Alexander the Great. His influence upon Alexander is not very obvious, however.
Aristotle's theories about drama, in particular the idea of the dramatic unities, influenced later playwrights, especially in France. He claimed to be describing the Greek theatre, but his work was taken as prescriptive.
The popularity of Neo-Platonism in late antiquity meant that little of Aristotles works was available in Latin in the early Middle Ages. By the 12th century there was a great revival of interest in Aristotelianism, and the great translator William of Moerbeke worked from both Greek and Arabic manuscripts to produce Latin translations. Aristotle's works were commented on by Thomas Aquinas and became the standard philosophical approach of the high and later middle ages.
See also: Aristotles theory of universals
The greatest of heathen Philosophers, born at Stagira, a Grecian colony in the Thracian peninsula Chalcidice, 384 B.C.; died at Chalcis, in Euboea, 322 B.C.
His father, Nicomachus, was court physician to King Amyntas of Macedonia. This position, we have reason to believe, was held under various predecessors of Amyntas by Aristotle's ancestors, so that the profession of medicine was in a sense hereditary in the family. Whatever early training Aristotle received was probably influenced by this circumstance; when, therefore at the age of eighteen he went to Athens his mind was already determined in the direction which it afterwards took, the investigation of natural phenomena.
From his eighteenth to his thirty-seventh year he remained at Athens as pupil of Plato and was, we are told, distinguished among those who gathered for instruction in the Grove of Academus, adjoining Plato's house. The relations between the renowned teacher and his illustrious pupil have formed the subject of various legends, many of which represent Aristotle in an unfavourable light. No doubt there were divergencies of opinion between the master, who took his stand on sublime, idealistic principles, and the scholar, who, even at that time, showed a preference for the investigation of the facts and laws of the physical world. It is probable that Plato did, indeed, declare that Aristotle needed the curb rather than the spur; but we have no reason to believe that there was an open breach of friendship. In fact, Aristotle's conduct after the death of Plato, his continued association with Xenocrates and other Platonists, and his allusions in his writings to Plato's doctrines, prove that while there were differences of opinion between teacher and pupil, there was no lack of cordial appreciation, or of that mutual forbearance which one would expect from men of lofty character. Besides this, the legends, so far as they reflect unfavourably on Aristotle, are traceable to the Epicureans who were known to antiquity as calumnators by profession; and if such legends were given wide circulation by patristic writers, such as Justin Martyr and Gregory Nazianzen, the reason is to be sought not in any well-grounded historical tradition, but in the exaggerated esteem in which Aristotle was held by the heretics of the early Christian period.
After the death of Plato (347 B.C.), Aristotle went, in company with Xenocrates, to the court of Hermias ruler of Atarneus in Asia Minor, whose niece and adopted daughter, Pythias, he married. In 344 Hermias having been murdered in a rebellion of his subjects, Aristotle went with his family to Mytilene and thence, one or two years later, he was summoned to his native Stagira by King Philip of Macedon, to become the tutor of Alexander, who was then in his thirteenth year. Whether or not we believe Plutarch when he tells us that Aristotle not only imparted to the future world-conqueror a knowledge of ethics and politics, but also initiated him into the most profound secrets of philosophy, we have positive proof, on the one hand, that the royal pupil profited by contact with the philosopher, and, on the other hand, that the teacher made prudent and beneficial use of his influence over the mind of the young prince. It was due to this influence that Alexander placed at the disposal of his teacher ample means for the acquisition of books and the pursuit of his scientific investigation, and history is not wrong in tracing to the intercourse with Aristotle those singular gifts of mind and heart which almost up to the very last distinguished Alexander among the few who have known how to make moderate and intelligent use of victory. About the year 335 Alexander departed for his Asiatic campaign; thereupon Aristotle, who, since his pupil's accession to the throne of Macedonia had occupied the position of a more or less informal adviser, returned to Athens and there opened a school of philosophy. He may, as Gellius says, have conducted a school of rhetoric during his former residence in the city; but now, following the example of Plato, he gave regular instruction in philosophy choosing for that purpose a gymnasium dedicated to Apollo Lyceios, from which his school has come to be known as the Lyceum. It was also called the Peripatetic School because it was the master's custom to discuss problems of philosophy with his pupils while walking up and down (peripateo) the shaded walks (peripatoi) around the gymnasium.
During the thirteen years (335-322) which he spent as teacher at the Lyceum, Aristotle composed the greater number of his writings. Imitating the example of his master, he placed in the hands of his pupils "Dialogues" in which his doctrines were expounded in somewhat popular language. Besides he composed the several treatises (of which mention will be made below) on physics, metaphysics, and so forth, in which the exposition is more didactic and the language more technical than in the "Dialogues". These writings show to what good use he put the means placed at his disposal by Alexander. They show in particular how he succeeded in bringing together the works of his predecessors in Greek philosophy, and how he spared neither pains nor expense in pursuing, either personally or through others, his investigations in the realm of natural Phenomena. When we read the works treating of zoology we are quite prepared to believe Pliny's statement that Alexander placed under Aristotle's orders all the hunters, fishermen, and fowlers of the royal kingdom and all the overseers of the royal forests, lakes, ponds and cattle-ranges, and when we observe how fully Aristotle is informed concerning the doctrines of those who preceded him, we are prepared to accept Strabo's assertion that he was the first who accumulated a great library. During the last years of Aristotle's life the relations between him and his former royal pupil became very much strained, owing to the disgrace and punishment of Callisthenes whom he had recommended to the King. Nevertheless, he continued to be regarded at Athens as a friend of Alexander and a representative of the Macedonian dominion. Consequently, when Alexander's death became known at Athens, and the outbreak occurred which led to the Lamian war, Aristotle was obliged to share in the general unpopularity of the Macedonians. The charge of impiety, which had been brought against Anaxagoras and Socrates, was now, with even less reason, brought against him. He left the city, saying (according to many ancient authorities) that he would not give the Athenians a chance to sin a third time against Philosophy. He took up his residence at his country house, at Chalcis, in Euboea, and there he died the following year, 322 B.C. His death was due to a disease from which he had long suffered. The story that his death was due to hemlock poisoning, as well as the legend, according to which he threw himself into the sea "because he could not explain the tides" are absolutely without historical foundation.
Very little is known about Aristotle's personal appearance except from sources manifestly hostile. There is no reason, however, to doubt the faithfulness of the statues and busts coming down to us, possibly from the first years of the Peripatetic School, which represent him as sharp and keen of countenance, and somewhat below the average height. His character, as revealed by his writings, his will (which is undoubtedly genuine), fragments of his letters and the allusions of his unprejudiced contemporaries, was that of a high-minded, kind-hearted man, devoted to his family and his friends, kind to his slaves, fair to his enemies and rivals, grateful towards his benefactors -- in a word, an embodiment of those moral ideals which he outlined in his ethical treatises, and which we recognize to be far above the concept of moral excellence current in his day and among his people. When Platonism ceased to dominate the world of Christian speculation, and the works of the Stagirite began to be studied without fear and prejudice, the personality of Aristotle appeared to the Christian writers of the thirteenth century, as it had to the unprejudiced pagan writers of his own day, calm, majestic, untroubled by passion, and undimmed by any great moral defects, "the master of those who know".
Aristotle defines philosophy in terms of essence, saying that philosophy is "the science of the universal essence of that which is actual". Plato had defined it as the "science of the idea", meaning by idea what we should call the unconditional basis of phenomena. Both pupil and master regard philosophy as concerned with the universal; the former however, finds the universal in particular things, and calls it the essence of things, while the latter finds that the universal exists apart from particular things, and is related to them as their prototype or exemplar. For Aristotle, therefore, philosophic method implies the ascent from the study of particular phenomena to the knowledge of essences, while for Plato philosophic method means the descent from a knowledge of universal ideas to a contemplation of particular imitations of those ideas. In a certain sense, Aristotle's method is both inductive and deductive, while Plato's is essentially deductive. In other words, for Plato's tendency to idealize the world of reality in the light of intuition of a higher world, Aristotle substituted the scientific tendency to examine first the phenomena of the real world around us and thence to reason to a knowledge of the essences and laws which no intuition can reveal, but which science can prove to exist. In fact, Aristotle's notion of philosophy corresponds, generally speaking, to what was later understood to be science, as distinct from philosophy. In the larger sense of the word, he makes philosophy coextensive with science, or reasoning: "All science (dianoia) is either practical, poetical or theoretical." By practical science he understands ethics and politics; by poetical, he means the study of poetry and the other fine arts; while by theoretical philosophy he means physics, mathematics, and metaphysics. The last, philosophy in the stricter sense, he defines as "the knowledge of immaterial being," and calls it "first philosophy", "the theologic science" or of "being in the highest degree of abstraction." If logic, or, as Aristotle calls it, Analytic, be regarded as a study preliminary to philosophy, we have as divisions of Aristotelean phllosophy (1) Logic; (2) Theoretical Philosophy, including Metaphysics, Physics, Mathematics, (3) Practical Philosophy; and (4) Poetical Philosophy.