Such is an imperfect sketch of Aristotle's general doctrine of physics. His opinions respecting man may be shortly summed up. The prin ciples of the soul and of animal life he thought to be identical, giving them the common designation of entelecheia (IrreAexela), or perfect energy. The faculties of the soul he considered to be, the nutritive, by which life is produced and preserved ; the sensitive, by which we perceive and feel ; and the rational, by which we understand. The sensitive faculty takes cognisance of external objects by means of its organs, which are adapted to produce the various sensations of sight, hearing, /cc. The senses receive forms or sensible species in the same manner as wax receives the impression of a seal Fancy is the perception which results from the immediate operation of the senses ; while memory is derived from fancy, and is the effect of images formed in the soul by the senses. The intellectual or rational faculty is of two kinds, either active or passive. Passive iutellect receives the form of things, and is the seat of species. Active intellect is either simple or complex : simple when it engages in the close apprehension of its object; complex when it combines simple conceptions so as to engender belief. Intellectual action is theoretical when it contemplates what is simply true or false, and practical when it determines what is good or evil, and thus gives rise to volition.
Whether Aristotle believed in the immortality of the soul or not, has not been clearly ascertained. From his notion that the soul is a power externally transmitted into the body, it has been inferred that he held it to be mortal, and that it ceased to have a separate existence after the dissolution of the body.
Aristotle's school in the Lyceum was continued for about twelve years. In consequence of the hostility of his enemies, who accused him of propagating impious tenets, he retired, soon after the death of Alexander, to Chalcis, where he died. Before withdrawing from his public labours however be appointed Theophrastus, of Eresus in Lesbos, his successor in the chair. The opinions of Theophrastus differed in some respects from those of Aristotle, but he taught with great success, and was attended by about two thousand scholars. He was followed consecutively by Straton of Lampsacus, Lycon, or Glycon of Tress, Ariston of Ceos, and Critolaus the Lycian. With Diodorus of Tyre, who came immediately'after Critolaus, the uninterrupted suc cession of the Peripatetic school terminated, about the 140th Olympiad. Among the early followers of the Stagirite, who did not fill the chair, were several eminent philosophers. The most distinguished of these were Diawarchus, a Messenian, Eudemus of Rhodes, and Demetrius Phalereus.
The Peripatetic doctrines were introduced into Rome in common with the other branches of the Greek philosophy by the embassy of Critolaus, Carneades, and Diogenes, but were little known till the time of Sylla. Tyrannion, an eminent grammarian, and Andronicus Ithodius, were the first who brought the writings of Aristotle and Theophrastus into notice. The obscurity of Aristotle's writings tended much to hinder the success of his philosophy, but it nevertheless soon gained a considerable number of supporters. During the reign of the Ciesars, it acquired all its ancient influence ; and till the time of Ammonius, the DD preceptor of Plutarch, was taught with great purity. After that it
was divided into two sects, consisting respectively of those who wished to adhere strictly to Aristotle, and theft who were disposed to amalga mate his doctrines with those of other schools. Julius Cesar and Augustus patronised the Peripatetio philosophy. Under Tiberius, Caligula, and Claudine, its adherents, in common with those of other sects, were either banished or obliged to remain silent on the subject of their peculiar tenets. This was the case also during the greater part of the reign of Nero, although during the early part of it philo sophy was favoured. The chief Peripatetics in the first century of the Roman empire were Sosigenes of Egypt, who wrote a commentary on Aristotle's treatise' De Ccelo: Boethus of Sidon, who is mentioned by Strabo as having been his fellow-student in the Aristotelian philosophy, and Nicolaus of Damascus in Syria.
Ammonium the Peripatetic made great exertions to extend the authority of Aristotle ; but about his time the Platonists began to study his writings, and prepared the way for the establishment of the Eclectic Peripatetic, under Ammouins Samar', who flourished about a century subsequent to Ammonius the Peripatetic. Even after this period however some were ?till found who adhered exclusively to Aristotle. The most celebrated of these was Alexander of Aphrodi sins, who was a public professor of the Peripateticphilosophy, under Septimius Severus, in Alexandria or in Athens. Many of the Eclectic Aristotelians wrote commentaries on his works, some of which are still extant. The principal of these writers were Themistius, who flourished during the reigns of Constantius and Theodosius the Great; Olympia dorm!, who lived about a century later : and Simplicius Cilix, in the time of the emperor Justinian.
After this period, philosophy in general languished. But in that mixture of ancient opinions with theological dogmas which constituted the philosophy of the middle age, the system of Aristotle undoubtedly predominated. About the 12th century it had many adherents among the Saracens and Jews, particularly in Spain ; and at the same period also it began to be diligently studied, though not without much oppo sition, among the ecclesiastics of the Christian church. Out of this latter circumstance gradually arose the Scholastic philosophy, which took its tone and complexion from the writings of Aristotle, and which continued long to perplex the minds of men with its frivolous though subtile speculations. The authority of Aristotle received a severe shock at the Reformation, but it survived the fall of the Scholastic system. His opinions were patronised by the Roman Catholic church, on account of their supposed favourable bearing on certain doctrines of faith ; and although Luther and others of the Reformers determinedly opposed them, they were maintained by such men as yhelanethon, who himself commented on certain portions of the works of the Stagirite. Many individuals distinguished for their genius and learning exerted themselves to revive the Peripatetic philosophy in its primitive purity, nor did it °ease to have numerous illustrious supporters until the time of Bacon, Grotius, and Des Cartes.