# 1911 Encyclopædia Britannica/Ionian School of Philosophy

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​IONIAN SCHOOL OF PHILOSOPHY. Under this name are included a number of philosophers of the 6th and 5th centuries B.C. Mainly Ionians by birth, they are united by a local tie and represent all that was best in the early Ionian intellect. It is a most interesting fact in the history of Greek thought that its birth took place not in Greece but in the colonies on the Eastern shores of the Aegean Sea. But not only geographically do these philosophers form a school; they are one in method and aim. They all sought to explain the material universe as given in sensible perception; their explanation was in terms of matter, movement, force. In this they differed from the Eleatics and the Pythagoreans who thought in the abstract, and explained knowledge and existence in metaphysical terminology. In tracing the development of their ideas, two periods may be distinguished. The earliest thinkers down to Heraclitus endeavoured to find a material substance of which all things consist; Heraclitus, by his principle of universal flux, took a new line and explained everything in terms of force, movement, dynamic energy. The former asked the question, “What is the substratum of the things we see?”; the latter, “How did the sensible world become what it is; of what nature was the motive force?”
The first name in the list of the Ionian philosophers—and, indeed, in the history of European thought—is that of Thales (q.v.). He first, so far as we know, sought to go behind the infinite multiplicity of phenomena in the hope of finding an infinite unity from which all difference has been evolved. This unity he decided is Water (πάντα ὕδωρ ἐστίν). It is impossible to discover precisely what he conceived to be the relation of this unity to the plurality of phenomena. Later writers from whom we derive our knowledge of Thales attributed to him ideas which seem to have been conceived by subsequent thinkers. Thus the suggestion preserved by Stobaeus that he conceived water to be endowed with mind is discredited by the specific statement of Aristotle that the earlier physicists (physiologi) did not distinguish the material from the moving cause, and that before Anaxagoras no one postulated creative intelligence. Again in the De anima (i. 5) Aristotle quotes the statement that Thales attributed to water a divine intelligence, and criticizes it as an inference from later speculations. It is probably safest to credit Thales with the bare mechanical conception of a universal material cause, leaving pantheistic ideas to a later period of thought.
The successors of Thales were Anaximander and Anaximenes, who also sought for a primal substance of things. Anaximander postulated a corporeal substance intermediate between air and fire on the one hand, and between earth and water on the other hand. This substance he called “the Infinite” (τὸ ἄπειρον). Unlike Thales, he was struck by the infinite variety in things; he felt that all differences are finite, that they have emerged from primal unity (first called ἄρχη by him) into which they must ultimately return, that the Infinite One has been, is, and always will be, the same, indeterminate but immutable. Change, growth and decay he explained on the principle of mechanical compensation (διδόναι γὰρ αὐτὰ τίσιν καὶ δίκην τῆς ἀδικίας).
Anaximenes, pupil of Anaximander, seems to have rebelled against the extreme materialism of his master. Perceiving that air is necessary to life, that the universe is surrounded by air, he was convinced that out of air all things have resulted. The process by which things grow is twofold, condensation (πύκνωσις) and rarefaction (ἀραίωσις), or, in other words, heat and cold. From the former process result cloud, water and stone; from the latter, fire and aether. This theory is closely allied to that of Thales, but it is superior in that it specifies the processes of change. Further, it is difficult not to accept Cicero’s statement that Anaximenes made air a conscious deity; we are, at all events, justified in regarding Anaximenes as a link (perhaps an unconscious link) between crude Hylozoism (q.v.) and definitely metaphysical theories of existence.
We have seen that Thales recognized change, but attempted no explanation; that Anaximander spoke of change in two directions; that Anaximenes called these two directions by specific names. From this last, the transition to the doctrine of Heraclitus is easy. He felt that change is the essential fact of experience and pointed out that any merely physical explanation of plurality is inherently impossible. The Many is of Sense; Unity is of Thought. Being is intelligible only in terms of Becoming. That which is, is what it is in virtue of its perpetually changing relations (πάντα ῥεῖ καὶ οὐδὲν μένει). By this recognition of the necessary correlation of Being and Not-being, Heraclitus is in a very real sense the father of metaphysical and scientific speculation, and in him the Ionian school of philosophy reached its highest point. Yet there is reason to doubt the view of Hegel and Lassalle that Heraclitus recognized the fundamental distinction of subject and object and the relations of mind and matter. Like the early Ionians he postulated a primary substance, fire, out of which all things have emerged and into which all must return. This elemental fire is in itself a divine rational process, the harmony of which constitutes the law of the universe. Human knowledge consists in the comprehension of this all-pervading harmony as embodied in the manifold of perception; the senses are “bad witnesses” in that they report multiplicity as fixed and existent in itself rather than in its relation to the One. This theory gives birth to a sort of ethical by-product whose dominant note is Harmony, the subordination of the individual to the universal reason; moral failure is proportionate to the degree in which the individual declines to recognize his personal transience in relation to the eternal Unity. From the same principle there follows the doctrine of Immortality. The individual, like the phenomena of sense, comes out of the infinite and again is merged; hence on the one hand he is never a separate entity at all, while on the other hand he exists in the infinite and must continue to exist. Moreover, the soul approaches most nearly to perfection when it is least differentiated from elemental fire; it follows that “while we live our souls are dead within us, but when we die our souls are restored to life.” This doctrine is at once the assertion and the denial of the self, and furnishes a striking parallel between European thought in its earliest stages and the fundamental principles of Buddhism. Knowledge of the self is one with knowledge of the Universal Logos (Reason); such knowledge is the basis not only of conduct but of existence itself in its only real sense.
Thus far the Ionian philosophers had held the field of thought. Each succeeding thinker had more or less assumed the methods of Thales, and had approached the problem of existence from the empirical side. About the time of Heraclitus, however, there sprang up a totally new philosophical spirit. Parmenides and Zeno (see Eleatic School) enunciated the principle that “Nothing is born of nothing.” Hence the problem becomes a dialectical a priori speculation wherein the laws of thought transcend the sense-given data of experience. It was therefore left for the later Ionians to frame an eclectic system, a synthesis of Being and Not-being, a correlation of universal mobility and absolute permanence. This examination of diametrically opposed tendencies resulted in several different theories. It will be sufficient here to deal with Anaxagoras, Diogenes of Apollonia, Archelaus and Hippo, leaving Empedocles, Leucippus and Democritus to special articles (q.v.). The latter three do not belong strictly to the Ionian School.
Anaxagoras (q.v.) elaborated a quasi-dualistic theory according to which all things have existed from the beginning. Originally they existed in infinitesimal fragments, infinite in number and devoid of arrangement. Amongst these fragments were the seeds of all things which have since emerged by the process of aggregation and segregation, wherein homogeneous fragments came together. These processes are the work of Nous (νοῦς) which governs and arranges. But this Nous, or Mind, is not incorporeal; it is the thinnest of all things; its action on the particle is conceived materially. It originated a rotatory movement, which arising in one point gradually extended till the whole was in motion, which motion continues and will continue infinitely. By this motion things are gradually constructed not entirely of homogeneous particles (the homoeomerê, ὁμοιομερῆ) but in each thing with a majority of a certain kind of particle. It is this aggregation which we describe variously as birth, death, maturity, decay, and of which the senses give inaccurate reports. His vague dualism works a very distinct advance upon the crude hylozoism of the early Ionians (see Atom), and the criticisms of Plato and Aristotle show how highly his work was esteemed. The great danger is that we should credit him with more than he actually thought. His Nous was not a spiritual force; it was no omnipotent deity; it is not a pantheistic world-soul. But by isolating Reason from all other growths, by representing it as the motor-energy of the Cosmos, in popularizing a term which suggested personality and will, Anaxagoras gave an impetus to ideas which were the basis of Aristotelian philosophy in Greece and in Europe at large.
In Diogenes of Apollonia we find a return to Anaximenes. Diogenes (q.v.) began by insisting on the necessity of there being only one principle of things, herein contradicting the pluralism of Heraclitus. This principle is that of the universal homogeneity of nature; all ​things are at bottom the same, or interaction would be impossible (πάντα τὰ ἔοντα ἀπὸ τοῦ αὐτοῦ ἑτεροιοῦσθαι καὶ τὸ αὐτὸ εἶναι). This universal substance is Air. But Diogenes went much farther than Anaximenes by attributing to air not only infinity and eternity but also intelligence. This Intelligence alone would have produced the orderly arrangement which we observe in Nature, and is the basis of human thought by the physical process of inhalation.
Another pupil of Anaxagoras was Archelaus of Miletus (q.v.). His work was mainly the combination of previous views, except that he is said to have introduced an ethical side into the Ionian philosophy. “Justice and injustice,” he said, “are not natural but legal.” He endeavoured to overcome the dualism of Anaxagoras, and in so doing approached more nearly to the older Ionians.
The last of the Ionians whom we need mention is Hippo (q.v.), who, like Archelaus, is intellectually amongst the earlier members of the school. He thought that the source of all things was moisture (τὸ ὑγρόν), and is by Aristotle coupled with Thales (Metaphysics, A 3).
Bibliography.—Ritter and Preller, ch. i.; Zeller’s History of Greek Philosophy; J. Burnet, Early Greek Philosophy (1892); Fairbanks, The First Philosophers of Greece (1898); Grote, History of Greece, ch. viii.; Windelband, History of Ancient Philosophy (1899); Benn, The Greek Philosophers (1883) and The Philosophy of Greece (1898); Th. Gomperz, Greek Thinkers (Eng. trans. vol. i., L. Magnus, 1901).