Greek philosophy gave the first strictly rational answers in Western thought to basic questions about the universe and man. The origin and nature of the visible universe concerned the earliest philosophers, the pre-Socratics, from Thales in the 6th century b.c. to Democritus in the 5th, with a gradual shift to dominant interest in ethical or political life. In reaction against Sophistic relativism and the rhetorical basis of traditional Greek education, Socrates emphasized virtue as scientific knowledge. His disciple Plato and, in turn, Plato's student, Aristotle, mark the peak of Greek philosophy. Both attempted, in different ways, to establish firm scientific principles as guides for the investigation of the universe, the human mind, and human conduct. Other influential
philosophies, such as Stoicism and Epicureanism, arose in the wake of this period of keen intellectual activity. Finally, Plotinus's fusion of Platonic spirit with Aristotelian doctrines and some elements from Stoic thought is the last great movement in Greek philosophy.
The term "philosophy" itself is of Greek origin. Meaning "love of wisdom," it was attributed in biographical tradition (Diogenes Laërtius, Lives 1.12; 8.8) to Pythagoras, and suggested that wisdom is something divine and a man cannot be truly wise but only a lover of wisdom. Designating men who pursue wisdom, the term "philosophers" appears in a fragment of Heraclitus cited in the 2d or 3d century a.d. (H. Diels, Die Fragmente der Vorsokratiker: Griechisch und Deutsch, ed., W. Kranz, 3 v. [10th ed. Berlin 1960–61] 22B 35). At any rate, it was used in the 5th century b.c. by Herodotus as an established Ionian word. At that time the Greek term for wisdom (σοφία) signified skill in a quite general sense, while philosophy (φιλοσοφία) seems from the start to have been restricted to the intellectual. Yet it was never divorced by the Greeks from its bearing on practical and moral life. In its ancient use it also included natural history. In the time of Isocrates it could mean the proficiency given by rhetoric, and for Aristotle it still embraced mathematics and literary theory. (see philosophy.)
Ionia. Western philosophy originated in the Greek city-states of Ionia, along the coast of Asia Minor. By both ancient and modern historians it is seen assuming its distinctive form either with Thales of Miletus (fl. c. 585 b.c.) or with his townsman and pupil Anaximander (c. 610–546 b.c.). For generations, it is true, various conceptions of the world's origin had been handed down in mythological lore, and a treasury of aphoristic wisdom had accumulated with the traditional customs and laws. But none of these teachings had reached a level that could be called genuinely philosophical. With the better opportunities and greater leisure for thought in the progressing culture of the city-states, however, these active traditions helped to focus the attention of inquiring Greek minds upon the problems of the nature and origin of the visible universe and upon the questions of human destiny. The efforts to answer the questions from an all-embracing viewpoint and in strictly rational rather than in mythological terms constituted the beginnings of Greek philosophy.
Thales and Anaximander. To Thales is attributed an attempt to explain the whole universe in terms of development from one basic nature, water. For him the visible universe seemed to grow from water as from a seminal plasm, and to be continually nourished by water in the manner of a living organism. His teachings are known only through a vague oral tradition preserved in writings that do not go back further than Aristotle (4th century b.c.). Of his successor Anaximander there remains but one continuous fragment. In mythological language it proclaims that all existing things come from and pass away into a basic nature, indeterminately described as "the unlimited" (Gr. τò ἄπειρον), in a process by which they "make amends to one another for their injustice, according to the ordering of time" (Diels, 12B 1). Detailed testimonia in later tradition ascribe to Anaximander a well-developed rational explanation of this process of becoming and perishing. The continual cosmic change takes place through an eternal and intrinsic motion, conceived apparently after the manner of living development.
Anaximenes. In a short extant fragment the philosophical successor of Anaximander, Anaximenes of Miletus (fl. c. 525 b.c.), located the primitive vital nature in the air that surrounded the visible universe and that sustained it and kept it together as soul does body. Anaximenes explained the changes in the universe by rarefaction and condensation. His philosophical successors, Anaxagoras of Clazomenae and Archelaus (5th century b.c.) transferred their activities to Athens. Together with Diogenes of Apollonia (5th century b.c.), these men continued or deepened Anaximenes's conception of the universe as developing from a basic vital principle conditioned in one way or another by the character of air. From Anaximenes on, there was present the notion of soul as something of an airlike nature that guides and controls a living being.
Anaxagoras. With anaxagoras, the greatest of the Ionian physicists, there emerges the notion of mind (Nous) as a principle that regulates the whole cosmos and is participated by some things but not by all. For him, however, mind like soul seems to have remained on the level of a material thing in its nature and functioning. The philosophical notion of the spiritual was not yet present to be either affirmed or denied. The conception of the universe as growing from an original plasm in the manner of a living organism implied failure to encounter the problem of a first extrinsic cause such as a creator. At least in point of fact the question of an outside cause did not arise among the Ionians.
Heraclitus. The best known of all the Ionians, heraclitus of ephesus, was classed as a "sporadic" philosopher because he did not fit in with the Ionian or any other philosophical succession. He is the earliest philosopher the fragments of whose works are sufficiently numerous to exhibit a thoroughly meditated philosophy. These fragments reveal a penetrating view of the unity of things in the cosmos, a dynamic unity worked out through an all-pervading common direction and maintained by a continually changing balance of opposite tensions. The moral wisdom of Heraclitus in striving to establish a common pattern of action amid the perpetually varying circumstances of human conduct is astonishingly profound and has proved abiding in its philosophical appeal.
Italy. In the latter half of the 6th century b.c. an Ionian, Pythagoras of Samos, had emigrated to the southern coast of Italy and founded there a religious and cultural organization (see pythagoras and pythagoreans). The history of the Pythagoreans is very obscure. They cultivated the study of mathematics, and tried to explain the cosmos on a mathematical basis. Their efforts are rightly seen as the beginnings of the quantitative account of the physical universe. They emphasized education and moral guidance, explaining the virtues in mathematical terms. They are credited with a doctrine of transmigration of souls, and of the imprisonment of soul in body as in a tomb. In accord with the general pre-Socratic mentality, however, they do not seem to have reached any notion of the supersensible, nor to have shown any interest in seeking a creator for the cosmos.
Parmenides. Further north along the west coast of Italy, probably early in the 5th century b.c., parmenides of Elea wrote hexameters giving a vivid account of the universe in terms of being. From the viewpoint of being, all things formed for him one strictly limited and continuous whole, everywhere equal in respect to their being, without origin, change, or end. Through ordinary human cognition, nevertheless, a multiple and changing cosmos is set up for men by the ever varying proportions of two basic forms, light and darkness. This may be called the world of seeming (δόξα). Parmenides's achievement began a long chain of attempts to explain things in terms of being, proceeding through different types of dialectic and culminating in the development of metaphysics as a science.
Eleatics. In the middle of the 5th century b.c. the dialectical phase was operative in the teaching of zeno of elea, whose paradoxes on motion are still controversial, and in the doctrines of Melissus of Samos. Melissus, about whose life nothing is known with certainty, seems to have applied the Eleatic dialectic of being to the unlimited basic reality as conceived by the earlier Ionians. For that reason he is classed as an Eleatic. Xenophanes of Colophon (570–478? b.c.), an Ionian rhapsodist who traveled throughout the mainland of Greece, has been regarded traditionally as the founder of the Eleatic school, though without strictly historical foundation.
Other Centers. In Sicily, empedocles of Acragas stereotyped the four traditional Ionian opposites, hot and cold, dry and wet, into the more concrete fire, earth, air, and water. He called them the "roots of all" (πάντωνῥιζώματα), as though the cosmos grew from them in the fashion of living things. They became known in later tradition as the four Empedoclean elements. They were composed of ingenerate and indestructible particles, in accord with the Parmenidean doctrine that a being could not be generated or destroyed. Through mixture continually changing under the impulse of the two fundamental cosmic forces, love and strife, they were always combining and separating to form the actual universe.
Atomists. At Abdera in Thrace, Leucippus (5th century b.c.) and democritus gave a more profound explanation of the physical world in a doctrine known as atomism. The basic particles were "atomic" in the sense of indivisible, and were not subject to generation or alteration or destruction. In this way they were "being," and were in perpetual motion in a void that was existent yet characterized as "nonbeing." They were all of the same nature, differing only in shape, position, and arrangement. By joining and separating through the perpetual cosmic motion they constituted the universe. The soul consisted of spherical atoms, which on account of their shape were most mobile, and were identified with fire and heat. Most of the 300 and more fragments attributed to Democritus, however, are concerned with moral matters. They teach an ethics in which cheerfulness, coinciding with self-sufficiency and imperturbability and wellbeing, is the goal of human action. This goal is attained by moderation in accordance with the mean between excess and deficiency, and is promoted by wisdom just as health is promoted by the science of medicine.
Sophists. Protagoras of Abdera (c. 490–420 b.c.) and Gorgias of Leontini (c. 480–380 b.c.), a pupil of Empedocles, were outstanding representatives of the career teachers known in the 5th century as sophists or professors of wisdom. Throughout the cities of the Greek world they taught the rhetoric that could sway public assemblies and lead to political power. The fragments that remain from Protagoras and Gorgias indicate a conception of the universe in which everything is changing and relative, as though set up by ever-changing human cognition in the fashion of Parmenides's cosmos; this provided an excellent philosophical basis for a world that could be ruled by rhetoric.
Athens. In the last half of the 5th century b.c. Athens became the center of Greek philosophical activity. socrates, about whom very little detail is known except chronology and the manner of his death, exercised through his conversations a profound influence upon Athenian youth. He emphasized virtue, and taught that it consisted in knowledge. He wrote nothing, but became the central figure in a literary genre known as "Socratic discourses." In these discourses various writers exploited him, using him as a mouthpiece for their own teachings. His insistence on virtue as knowledge meant, according to Aristotle's comments, that virtuous conduct had to be based upon common and abiding notions of what virtue is, notions that could be expressed in stable definitions. This was in direct opposition to the rhetorical training given by the Sophists.
Lesser Socratics. The influence of Socrates's name was spread through the writings and teachings of his disciples. A number of these such as Aristippus of Cyrene (see cyrenaics), Euclides of Megara, and Antisthenes of Athens, are grouped under the designation "Lesser Socratics." In this way they are distinguished from Socrates's greatest pupil, Plato. Followers of Euclides, such as Eubulides of Miletus, Diodorus Cronus, and Philo of Megara, made notable contributions to the development of logic as a science (see logic, history of).
Plato and Aristotle. In plato and aristotle Greek philosophy reached its greatest splendor. The philosophical conception of realities above the whole order of extension and time, and therefore completely immaterial, made its first appearance in Western thought. For Plato these were the Ideas, the eternal natures of things. For Aristotle they were forms separate from matter, and different from the natures of any sensible things. The Platonic Idea and the Aristotelian form provided philosophical bases for the common definition urged by Socrates, and for the scientific knowledge built upon it. Both Plato and Aristotle developed highly articulated moral doctrines that aimed to achieve the common good by virtuous action, and in which one's private good was attained in the common political good. For both philosophers the norm of virtue was the mean between excess and defect. In the teaching of Aristotle, logic and the classification of the sciences reached a form that endured for centuries. The philosophical schools that stem from Plato and Aristotle are called respectively the Academy and the Peripatos (see platonism; aristotelianism).
Other Schools. In Aristotle's time a movement known as Cynicism (see cynics) had been started by Diogenes of Sinope (c. 410–320 b.c.). It rejected Greek social conventions and advocated living in accord with the simplicity of nature. It was a type of life made possible only by rigorous ascetic training, and was offered as a shortcut to virtue and happiness. Two other widespread schools originated at Athens toward the close of the 4th century b.c., the Garden, or school of epicurus, and the Stoa, or school of Zeno of Citium (see epicureanism; hedonism; stoicism). Both rejected the supersensible. Further, two types of skepticism developed among the Greeks, the one taking its name from Pyrrho of Elis (c. 365–275 b.c.), the other from the Platonic Academy in the 3d and 2d centuries b.c. (see pyrrhonism). During the first two centuries of the Christian Era the period of the Academy called "Middle Platonism" carried on the original Platonic traditions with the incorporation of teachings from other schools, while interest in Pythagorean doctrines resulted in a tendency called Neopythagoreanism. An eclectic school is reported (Diogenes Laërtius, Lives 1.21) to have selected its teachings from all the other schools (see eclecticism). Finally, the last Greek form of Platonism, called in the 19th century neoplatonism, was developed by plotinus. It penetrated deeply into Patristic thought. In a.d. 529 the schools at Athens were closed by Justinian and original movements in Greek philosophy came to an end.
Influence on Christian Thought. Philosophy was consistently looked upon as a way of life by the Greeks. Accordingly it was regarded by St. Paul (Col 2.8) as opposed to the new and divinely inspired way of life, Christianity. Nevertheless the influence especially of Stoic and Neoplatonic philosophy soon made itself felt in the vocabulary and external structure of Christian thinking, and in the 13th century direct contact with the works of Aristotle made a profound and lasting impression on the molds of Christian teaching. Acquaintance with Greek philosophy is therefore necessary to understand the written tradition of Christian thought. In this contact, however, Christian genius proved equal to the task of profiting by Greek intellectual methods without imbibing the accompanying pagan doctrines. The revival of scholastic methods in Catholic theology and philosophy during the late 19th and the 20th centuries has given renewed importance to Greek philosophy as an indispensable tool for the study and presentation of Christian doctrine on an intellectual basis.
See Also: philosophy, history of; greek philosophy (religious aspects); greek religion.
Bibliography: The only general history of Greek philosophy remaining from ancient times is diogenes laËrtius, Lives of Eminent Philosophers, tr. r. d. hicks, 2 v. (Loeb Classical Library ; New York 1925, reprint Cambridge, Mass. 1950). The fragments of the pre-Socratics are edited in h. diels, Die Fragmente der Vorsokratiker: Griechisch und Deutsch, ed. w. kranz, 3 v. (8th ed. Berlin 1956), and those of the early Stoics by h. f. von arnim, Stoicorum veterum fragmenta, 4 v. (Leipzig 1903–24). The best established modern history of Greek philosophy is e. zeller, Die Philosophie der Griechen, 3 v. in 6 (5th–7th ed. Leipzig 1920–23). In English, a comprehensive history was undertaken by w. k. c. guthrie, A History of Greek Philosophy, of which the first volume (Cambridge, England) was published in 1962. Shorter surveys are numerous, e.g.: e. c. copleston, Greece and Rome, v. 1 of A History of Philosophy (Westminster, Md. 1946–). a. h. armstrong, An Introduction to Ancient Philosophy (3d ed. London 1957). i. c. brady, A History of Ancient Philosophy (Milwaukee 1959). j. owens, A History of Ancient Western Philosophy (New York 1959). On the significance of Greek philosophy, see c. j. de vogel, "What Philosophy Meant to the Greeks," International Philosophical Quarterly 1 (1961) 35–37. Phronesis (1955–), a journal appearing twice a year, is dedicated largely to Greek philosophy. Studies in the field are listed in the Louvain quarterly Répertoire Bibliographique de la Philosophile, "Antiquité Grecque et Romaine" section.