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Aristotle

The Catholic Encyclopedia

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 philosophy (1) Logic; (2) Theoretical Philosophy, including Metaphysics, Physics, Mathematics, (3) Practical Philosophy; and (4) Poetical Philosophy.

Logic

Aristotle's logical treatises, constituting what was later called the "Organon", contain the first systematic treatment of the laws of thought in relation to the acquisition of knowledge. They form, in fact, the first attempt to reduce logic to a science, and consequently entitle their writer to be considered the founder of logic. They are six in number and deal respectively with:

• Classification of Notions,
• Judgments and Propositions,
• the Syllogism,
• Demonstration,
• the Problematic Syllogism, and
• Fallacies.

They thus cover practically the entire field of logical doctrine.

In the first treatise, the "Categories", Aristotle gives a classification of all concepts, or notions, according to the classes into which the things represented by the concepts or notions, naturally fall. These classes are substance, quantity, quality, relation, action, passion (not to be understood as meaning merely a mental or psychic condition), place, time, situation, and habit (in the sense of dress). They are carefully to be distinguished from the Predicables, namely, genus, species (definition), difference, property, and accident. The latter are, indeed, classes into which ideas fall, but only in so far as one idea is predicated of another. That is to say, while the Categories are primarily a classification of modes of being, and secondarily of notions which express modes of being, the Predicables are primarily a classification of modes of predication, and secondarily of notions or ideas, according to the different relation in which one idea, as predicate stands to another as subject. In the treatise styled "Analytica Priora", Aristotle treats the rules of syllogistic reasoning, and lays down the principle of induction. In the "Analytica Posteriora" he takes up the study of demonstration and of indemonstrable first principles. Besides, he treats of knowledge in general, its origin, process, and development up to the stage of scientific knowledge. From certain well-known passages in this treatise, and from his other writings, we are enabled to sketch his theory of knowledge. As was remarked above, Aristotle approaches the problems of philosophy in a scientific frame of mind. He makes experience to be the true source of all our knowledge, intellectual, as well as sensible. "There is nothing in the intellect that was not first in the senses" is a fundamental principle with him, as it was later on with the Schoolmen. All knowledge begins with sense-experience, which of course has for its object the concrete, particular, changeable phenomenon. But though intellectual knowledge begins with sense-experience, it does not end there, for it has for its object the abstract, universal, immutable essence. This theory of cognition is, so far, summed up in the principles: Intellectual knowledge is essentially dependent on sense-knowledge, and intellectual knowledge is, nevertheless, superior to sense-knowledge. How, then, does the mind pass from the lower knowledge to the higher? How can the knowledge of the sense-perceived (aistheton) lead to a knowledge of the intelligible (noeton)? Aristotle's answer is, that the mind discovers the intelligible in the sense-perceived. The mind does not, as Plato imagined, bring out of a previous existence the recollection of certain ideas, of which it is reminded at sight of the phenomenon. It brings to bear on the phenomenon a power peculiar to the mind, by virtue of which it renders intelligible essences which are imperceptible to the senses, because hidden under the non-essential qualities. The fact is, the individual substance (first substance) of our sense experience--this book, this table, this house--has certain individuating qualities (its particular size, shape, colour, etc.) which distinguish it from others of its species and which alone are perceived by the senses. But in the same substance, there is underlying the individuating qualities, its general nature (whereby it is a book, a table, a house); this is the second substance, the Essence, the Universal, the Intelligible. Now, the mind is endowed with the power of abstraction, generalization, or induction (Aristotle is not very clear as to the precise nature of this power) by which it removes, so to speak, the veil of particularizing qualities and thus brings out, or leaves revealed, the actually intelligible, or universal, element in things, which is the object of intellectual knowledge. In this theory intellectual knowledge is developed from sense-knowledge in so far as that Process may be called a development in which what was only Potentially intelligible is rendered actually intelligible by the operation of the active intellect. The Universal was in re before the human mind began to work, but it was there in a manner only potentially because, by reason of the individuating qualities which enveloped it, it was only potentially intelligible. Aristotle's theory of universals, therefore, is that

• The Universal does not exist apart from the particular, as Plato taught, but in particular things;
• The Universal as such, in its full-blown intelligibility, is the work of the mind, and exists in the mind alone though it has a foundation in the potentially universal essence which exists independently of the mind and outside the mind.

Theoretical philosophy

Metaphysics

Metaphysics, or, more properly, First Philosophy, is the Science of Being as Being. That is to say, although all sciences are concerned with being, the other sciences are concerned only with part of reality, while this science contemplates all reality; the other sciences seek proximate and particular causes while this science seeks the ultimate and universal causes; the other sciences study being in its lower determinations (quantity, motion, etc.), while this science studies Being as such, that is, in its highest determinations (substance, cause, goodness, etc.). The mathematician claims that a certain object comes within the scope of his science if it is circular or square, or in any other way endowed with quantity. Similarly, the physicist claims for his science whatever is endowed with motion. For the metaphysician it is sufficient that the object in question is a being. Like the human soul or God, the object may be devoid of quantity, and of all physical motion; yet so long as it is a being, it comes within the scope of metaphysics. The principal question, then, in First Philosophy is: What are the ultimate principles of Being, or of reality as Being? Here Aristotle passes in review the opinions of all his predecessors in Greek Philosophy from Thales to Plato, showing that each successive answer to the question just quoted was somehow defective. He devotes special attention to the Platonic theory, according to which ideas are the ultimate principles of Being. That theory, he contends was introduced to explain how things are, and how things are known; in both respects, it is inadequate. To postulate the existence of ideas apart from things is merely to complicate the problem; for, unless the ideas have some definite contact with things, they cannot explain how things came to be, or how they came to be known by us. Plato does not maintain in a definite, scientific way a contact between ideas and phenomena — he merely takes refuge in expressions, such as participation, imitation, which, if they are anything more than empty metaphors, imply a contradiction. In a word, Aristotle believes that Plato, by constituting ideas in a world separate from the world of phenomena, precluded the possibility of solving by means of ideas the problem of the ultimate nature of reality. What, then, are, according to Aristotle, the principles of Being? In the metaphysical order, the highest determinations of Being are Actuality (entelecheia) and Potentiality (dynamis). The former is perfection, realization, fullness of Being; the latter imperfection, incompleteness, perfectibility. The former is the determining, the latter the determinable principle. Actuality and potentiality are above all the Categories; they are found in all beings, with the exception of the Supreme Cause, in Whom there is no imperfection, and, therefore, no potentiality. He is all actuality, Actus Purus. All other beings are composed of actuality and potentiality, a dualism which is a general metaphysical formula for the dualism of matter and form, body and soul, substance and accident, the soul and its faculties, passive and active intellect. In the physical order, potentiality and actuality become Matter and Form. To these are to be added the Agent (Efficient Cause) and the End (Final Cause); but as the efficiency and finality are to be reduced, in ultimate analysis, to Form, we have in the physical order two ultimate principles of Being, namely, Matter and Form. The four generic causes--Material, Formal, Efficient, and Final--are seen in the case, for instance, of a statue:

• The Material Cause, that out of which the statue is made, is the marble or bronze.
• The Formal Cause, that according to which the statue is made, is the idea existing in the first place as exemplar in the mind of the sculptor, and in the second place as intrinsic, determining cause, embodied in the matter.
• The Efficient Cause, or Agent, is the sculptor.
• The Final Cause is that for the sake of which (as, for instance, the price paid the sculptor, the desire to please a patron, etc.) the statue is made.

All these are true causes in so far as the effect depends on them either for its existence or for the mode of its existence. Pre-Aristotelean philosophy either failed to discriminate between the different kinds of causes, confounding the material with the efficient principle, or insisted on formal causes alone as the true principles of Being, or, recognizing that there is a principle of finality, hesitated to apply that principle to the details of the cosmic Process. Aristotelean philosophy, by discriminating between the different generic causes and retaining at the same time, all the different kinds of causes which played a part in previous systems, marks a true development in metaphysical speculation, and shows itself a true synthesis of Ionian, Eleatic, Socratic, Pythagorean, and Platonic philosophy. A point which should be emphasized in the exposition of this portion of Aristotle's philosophy is the doctrine that all action consists in bringing into actuality what was somehow potentially contained in the material on which the agent works. This is true not only in the world of living things, in which, for example, the oak is potentially contained in the acorn, but also in the inanimate world in which heat, for instance, is potentially contained in water, and needs but the agency of fire to be brought out into actuality. Ex nihilo nihil fit. This is the principle of development in Aristotle's philosophy which is so much commented on in relation to the modern notion of evolution. Mere potentiality without any actuality or realization--what is called materia prima--nowhere exists by itself, though it enters into the composition of all things except the Supreme Cause. It is at one pole of reality, He is at the other. Both are real. Materia prima possesses what may be called the most attenuated reality, since it is pure indeterminateness, God possesses the highest and most complete reality, since He is in the highest grade of determinateness. To prove that there is a Supreme Cause is one of the tasks of metaphysics the Theologic Science. And this Aristotle undertakes to do in several portions of his work on First Philosophy. In the "Physics" he adopts and improves on Socrates's teleological argument, the major premise of which is, "Whatever exists for a useful purpose must be the work of an intelligence". In the same treatise, he argues that, although motion is eternal, there cannot be an infinite series of movers and of things moved, that, therefore, there must be one, the first in the series, which is unmoved, to proton kinoun akineton--primum movens immobile. In the "Metaphysics" he takes the stand that the actual is of its nature antecedent to the potential, that consequently, before all matter, and all composition of matter and form, of potentiality and actuality, there must have existed a Being Who is pure actuality, and Whose life is self-contemplative thought (noesis noeseos). The Supreme Being imparted movement to the universe by moving the First Heaven, the movement, however, emanated from the First Cause as desirable; in other words, the First Heaven, attracted by the desirability of the Supreme Being "as the soul is attracted by beauty", was set in motion, and imparted its motion to the lower spheres and thus, ultimately, to our terrestrial world. According to this theory God never leaves the eternal repose in which His blessedness consists. Will and intellect are incompatible with the eternal unchangeableness of His being. Since matter, motion, and time are eternal, the world is eternal. Yet, it is caused. The manner in which the world originated is not defined in Aristotle's philosophy. It seems hazardous to say that he taught the doctrine of Creation. This much, however, may safely be said: He lays down principles which, if carried to their logical conclusion, would lead to the doctrine that the world was made out of nothing.

Physics

Physics has for its object the study of "being intrinsically endowed with motion", in other words, the study of nature. For nature differs from art in this: that nature is essentially self-determinant from within, while art remains exterior to the products of art. In its self-determination, that is to say in its processes, nature follows an intelligent and intelligible form. "Nature is always striving for the best". Movement is a mode of being, namely, the condition of a potential being actualizing itself. There are three kinds of movement: quantitative (increase and decrease), qualitative (alteration) and spatial (locomotion). Space is neither matter nor form, but the "first and unmoved limit of the containing, as against the contained". Time is the measure of the succession of motion. In his treatment of the notions of motion, space, and time, Aristotle refutes the Eleatic doctrine that real motion, real space, and real succession imply contradictions. Following Empedocles Aristotle, also, teaches that all terrestrial bodies are composed of four elements or radical principles, namely: fire, air, earth, and water. These elements determine not only the natural warmth or moisture of bodies, but also their natural motion, upward or downward, according to the preponderance of air or earth. Celestial bodies are not constituted by the four elements but by ether, the natural motion of which is circular. The Earth is the centre of the cosmic system; it is a spherical, stationary body, and around it revolve the spheres in which are fixed the planets. The First Heaven, which plays so important a part in Aristotle's general cosmogonic system, is the heaven of the fixed stars. It surrounds all the other spheres and, being endowed with intelligence, it turned toward the Deity, drawn, as it were, by His Desirability, and it thus imparted to all the other heavenly bodies the circular motion which is natural to them. These doctrines, as well as the general concept of nature as dominated by design or purpose, came to be taken for granted in every philosophy of nature down to the time of Newton and Galileo, and the birth of modern physical science.

Psychology in Aristotle's philosophy is treated as a branch of physical science. It has for its object the study of the soul, that is to say, of the principle of life. Life is the power of self-movement, or of movement from within. Plants and animals, since they are endowed with the power of adaptation, have souls, and the human soul is peculiar only in this, that to the vegetative and sensitive faculties, which characterize plant-life and animal life respectively it adds the rational faculty--the power of acquiring universal and intellectual knowledge. It must therefore be borne in mind that when Aristotle speaks of the soul he does not mean merely the principle of thought; he means the principle of life. The soul he defines as the form, actualization, or realization of the body, "the first entelechy of the organized body possessing the power of life". It is not a substance distinct from the body, as Plato taught but a co-substantial Principle with the body, both being united to form the composite substance, man. The faculties or powers of the soul are five-fold: nutritive, sensitive, appetitive, locomotive, and rational. Sensation is defined as the faculty "by which we receive the forms of sensible things without the matter, as the wax receives the figure of the seal without the metal of which the seal is composed". It is "a movement of the soul", the "form without the matter" being the stimulus which calls forth that movement. The typos, as that form is called, while it is analogous to the "effluxes" about which the Atomists spoke, is not like the efflux, a diminished object, but a mode of motion, mediating between the object and the faculty. Aristotle distinguishes between the five external senses and the internal senses, of which the most important are the Central sense and the Imagination. Intellect (nous) differs from the senses in that it is concerned with the abstract and universal, while they are concerned with the concrete and particular. The natural endowment of intellect is not actual knowledge, but merely the power of acquiring knowledge. The mind "is in the beginning without ideas, it is like a smooth tablet on which nothing is written". All our knowledge, therefore, is acquired by a process of elaboration or development of sense-knowledge. In this process the intellect exhibits a two-fold phase an active and a passive. Hence it is customary to speak of the Active and Passive Intellect, though it is by no means clear what Aristotle meant by these concepts. The corruption of the text in some of the most critical passages of the work "On the Soul"--the mixture of Stoic pantheism, in the explanation of the earlier commentators, not to speak of the later addition of extraneous elements on the part of the Arabian, Scholastic, and modern transcendentalist expounders of the text--have rendered it impossible to say precisely what meaning to attach to the terms Active and Passive Intellect. It is enough to remark here that:

• according to the Scholastics Aristotle understood both Active and Passive Intellect to be parts, or phases, of the individual mind;
• according to the Arabians and some earlier commentators, the first of these, perhaps, being Aristocles, he understood the Active Intellect to be a divine something, or at least something transcending the individual mind;
• according to some interpreters the Passive Intellect is not properly an intellectual faculty at all, but merely the aggregate of sensations out of which ideas are made, as the statue is made out of the marble.

From the fact that the soul in its intellectual operations attains a knowledge of the abstract and universal, and thus transcends matter and material conditions, Aristotle argues that it is immaterial and immortal. The will, or faculty of choice, is free, as is proved by the recognized voluntariness of virtue, and the existence of reward and punishment.

Mathematics

Mathematics was recognized by Aristotle as a division of philosophy, co-ordinate with physics and metaphysics, and is defined as the science of immovable being. That is to say, it treats of quantitative being, and does not, like physics, confine its attention to being endowed with motion.

Practical philosophy

This includes ethics and politics. The starting-point of ethical inquiry is the question: In what does happiness consist? Aristotle answers that man's happiness is determined by the end or purpose of his existence, or in other words, that his happiness consists in the "good proper to his rational nature". For man's prerogative is reason. His happiness, therefore, must consist in living conformably to reason, that is, in living a life of virtue. Virtue is the perfection of reason, and is naturally twofold, according as we consider reason in relation to the lower powers (moral virtue) or in relation to itself (intellectual, or theoretical, virtue). Moral virtue is defined "a certain habit of the faculty of choice, consisting in a mean suitable to our nature and fixed by reason, in the manner in which prudent men would fix it". It is of the nature of moral virtues, therefore, to avoid all excess as well as defect; bashfulness, for example, is as much opposed to the virtue of modesty as shamelessness is. The intellectual virtues (understanding, science, wisdom, art, and practical wisdom) are perfections of reason itself, without relation to the lower faculties. It is a peculiarity of Aristotle's ethical system that he places the intellectual virtues above the moral, the theoretical above the practical, the contemplative above the active, the dianœtical above the ethical. An important constituent of happiness, according to Aristotle, is friendship, the bond between the individual and the social aggregation, between man and the State. Man is essentially, or by nature, a "social animal", that is to say, he cannot attain complete happiness except in social and political dependence on his fellow man. This is the starting point of political science. That the State is not absolute, as Plato taught, that there is no ideal State, but that our knowledge of political organization is to be acquired by studying and comparing different constitutions of States, that the best form of government is that which best suits the character of the people--these are some of the most characteristic of Aristotle's political doctrines.

Poetical philosophy

Under this head came Aristotle's theory of art and his analysis of the beautiful. When Aristotle defines the purpose of art to be "the imitation of nature" he does not mean that the plastic arts and poetry should merely copy natural productions; his meaning is that as nature embodies the idea so also does art, but in a higher and more perfect form. Hence his famous saying that poetry is "more philosophical and elevated than history". Hence his equally famous doctrine that the aim of art is the calming, purifying (katharsis) and ennobling of the affections. For this reason, he prefers music to the plastic arts because it possesses a higher ethical value.

Aristotle's conception of beauty is vague and undefined. At one time he enumerates order, symmetry, and limitation, at another time merely order and grandeur, as constituents of the beautiful. These latter qualities he finds especially in moral beauty. It is impossible here to give an estimate of Aristotle's philosophy as a whole or to trace its influence on subsequent philosophical systems. Suffice it to say that, taken as a system of knowledge, it is scientific rather than metaphysical; its starting-point is observation rather than intuition; and its aim, to find the ultimate cause of things rather than to determine the value (ethical or æsthetic) of things. Its influence extended, and still extends, beyond the realms of science and philosophy. Our thoughts, even on subjects far removed from science and philosophy, fall naturally into the Categories and formulas of Aristoteleanism, and often find expression in terms which Aristotle invented, so that "the half-understood words of Aristotle have become laws of thought to other ages".

The identity of the Aristotelean School was preserved from the time of Aristotle's death down to the third century of the Christian era by the succession of Scholarchs, or official heads of the school. The first of these — Theophrastus — as well as his immediate successor Strato, devoted special attention to developing Aristotle's physical doctrines. Under their guidance also, the school interested itself in the history of philosophical and scientific problems. In the first century B.C. Andronicus of Rhodes edited Aristotle's works, and thereafter the school produced the most famous of its commentators, Aristocles of Messene and Alexander of Aphrodisias (about A.D. 200). In the third century the work of commentating was continued by the Neo-Platonic and Eclectic philosophers, the most famous of whom was Porphyry. In the fifth and sixth centuries the chief commentators were John Philoponus and Simplicius, the latter of whom was teaching at Athens when, in the year 529, the Athenian School was closed by order of the Emperor Justinian. After the close of the Athenian School the exiled philosophers found temporary refuge in Persia. There, as well as in Armenia and Syria, the works of Aristotle were translated and explained. Uranius, David the Armenian, the Christians of the Schools of Nisibis and Edessa, and finally Honain ben Isaac, of the School of Bagdad, were especially active as translators and commentators. It was from the last-named school that, about the middle of the ninth century, the Arabians, who under the reign of the Abassides, experienced a literary revival similar to that of Western Europe under Charlemagne, and obtained their knowledge of Aristotle's writings. Meantime there had been preserved at Byzantium a more or less intermittent tradition of Aristotelean learning, which, having been represented in successive centuries by Michael Psellus, Photius, Arethas, Nicetas, Johannes Italus, and Anna Comnena, obtained its highest development in the twelfth century, through the influence of Michael Ephesius. In that century the two currents the one coming down through Persia, Syria, Arabia, and Moorish Spain, and the other from Athens through Constantinople, met in the Christian schools of Western Europe, especially in the University of Paris. The Christian writers of the patristic age were, with few exceptions, Platonists, who regarded Aristotle with suspicion, and generally underrated him as a philosopher. The exceptions to be found were John of Damascus, who in his "Source of Science" epitomizes Aristotle's "Categories" and "Metaphysics", and Porphyry's" Introduction"; Nemesius, Bishop of Emesa, who in his "Nature of Man" follows in the footsteps of John of Damascus; and Boethius, who translated several of Aristotle's logical treatises into Latin. These translations and Porphyry's "Introduction" were the only Aristotelean works known to the first of the Schoolmen, that is to say, to the Christian philosophers of Western Europe from the ninth to the twelfth century. In the twelfth century the Arabian tradition and the Byzantine tradition met in Paris, the metaphysical, physical, and ethical works of Aristotle were translated partly from the Arabian and partly from the Greek text, and, after a brief period of suspicion and hesitancy on the part of the Church, Aristotle's philosophy was adopted as the basis of a rational exposition of Christian dogma. The suspicion and hesitation were due to the fact that, in the Arabian text and its commentaries, the teaching of Aristotle had become perverted in the direction of materialism and pantheism. After more than two centuries of almost universally unquestioned triumph, Aristotle once more was made the subject of dispute in the Christian schools of the Renaissance Period, the reason being that the Humanists, like the Arabians, emphasized those elements in Aristotle's teaching that were irreconcilable with Christian doctrine. With the advent of Descartes, and the shifting of the centre of philosophical inquiry from the external world to the internal, from nature to mind, Aristoteleanism, as an actual system, began to be more and more identified with traditional scholasticism, and was not studied apart from scholasticism except for its historic interest.

It is customary to distinguish, on the authority of Gellius, two classes of Aristotelean writings: the exoteric, which were intended for the general Public, and the acroatic, which were intended merely for the limited circle of those who were well versed in the phraseology and modes of thought of the School. To the former class belonged the "Dialogues", of which the best known were the "Eudemus", three books on "Philosophy", four books "On Justice", also the treatises (not in dialogue form) "On the Good", and "On Ideas", all of which are unfortunately lost. Under this head mention should be made also of the "Poems", "Letters", "Orations", "Apology", etc., which were at one time ascribed to Aristotle, though there can be little doubt of their spuriousness. To the class of acroatic writings belong all the extant works and also the lost treatises, anatomai (containing anatomical charts) peri phytonand the politeiai (a collection of the different political constitutions of the Greek States; a portion, giving the Constitution of Athens was discovered in an Egyptian papyrus and published in 1891). The extant works may be arranged in the following classes, with the Latin titles by which they are generally cited:

Logical treatises

These were known to the Byzantine writers as the "Organon", including (1) "Categoriae"; (2) "De Interpretatione"; (3) "Analytica Priora"; (4) "Analytica Posteriora"; (5) "Topica"; (6) "De Sophisticis Elenchis".

Metaphysical treatises

The work commonly cited as "Metaphysica" or "Metaphysics" was (or, at least, a portion of it was) entitled by Aristotle "First Philosophy" (prote philosophia). The title meta ta physika was first given it by Andronicus of Rhodes in whose collection, or edition, of Aristotle's works it was placed after the physical treatises.

Physical treatises

(1) "Physica", or "Physica Auscultatio", commonly called Physics; (2) "De Cœlo"; (3) "Meteorologica".

Biological and zoological treatises

(1) "Historiae Animalium"; (2) "De Generatione et Corruptione"; (3) "De Generatione Animalium"; (4) "De Partibus Animalium".

Psychological and anthropological treatises

(1) "De Anima"; (2) "De Sensu et Sensibili"; (3) "De Memoria et Reminiscentia", (4) "De Vita et Morte"; (5) "De Longitudine et Brevitate vitae".

Ethical and political treatises

(1) "Ethica Nicomachea"; (2) "Politica". The "Eudemian Ethics" and the "Magna moralia" are not of directly Aristotelean authorship.

Poetical and rhetorical treatises

(1) "De Poeticâ"; (2) "De Rhetoricâ"; both of these are genuine only in parts.

Of the extant works, some were written in their present form and were intended for finished scientific expositions. Others, though written by Aristotle, were intended merely for lecture notes, to be filled out in oral teaching. Others, finally, are nothing but the notes jotted down by his pupils, and were never retouched by the master. This consideration, it is obvious, leads the student of Aristotle to attach very different values to different parts of the text; no one, for example, would think of attaching to a citation from the First Book of the "Metaphysics" the same value as to a quotation from the Second Book. According to a well-known story, first told by Strabo and repeated by Plutarch and Suidas, Aristotle's library, including the manuscripts of his own works, was willed by him to Theophrastus, his successor as head of the Peripatetic School. By Theophrastus it was bequeathed to his heir, Neleus of Scepsis. After Neleus's death the manuscripts were hidden in a cellar or pit in order to avoid confiscation at the hands of royal book collectors, and there they remained for almost two centuries, until in Sulla's time they were discovered and brought to Rome. At Rome they were copied by a grammarian named Tyrannion and edited (about 70 B.C.) by Andronicus of Rhodes. The substance of this story may be regarded as true; the inference, however, that during all that time there was no copy of Aristotle's writings available, is not warranted by the facts. It is not implied in Strabo's narrative, nor is it in itself probable. One or two books may have been lost to the School until Andronicus's edition appeared; but the same cannot be true of the whole Corpus Aristotelicum. Andronicus's edition remained in use in the Peripatetic School during the first few centuries of our era. For the various translations of the text into Syriac, Arabic, Latin, etc., see preceding.