Xenophanes of Colophon (?570-48o B.c.), the founder of the Eleatic school, is chiefly noteworthy for his very scathing attack on the Homeric, Hesiodic and similar anthropomorphic concep tions of the gods. "Mortals," he remarked, "believe that the gods come into being as they themselves do, that they have senses, voice, body. . . . But if oxen or lions had hands, oxen would make gods like oxen, horses would make gods like horses." He himself believed in one God, altogether different from man. "There is one supreme God . . . like to mortals neither in body nor in thought." In fact, Xenophanes was a pantheist, as seems clear from his reported utterance : "The All is One, and the One is God." At all events this conception of the unity of Being or of ultimate reality, became the leading tenet of his school.
Parmenides of Elea (?54o-48o B.c.) was the most important member of the Eleatic group. He is reported to have considered things "from the standpoint of the notion," that is, presumably, from the standpoint of their being intelligible or thinkable. The chief doctrines ascribed to him are expressed in the statements : "only Being is"; "birthless it is and deathless . . . for ever it stands a continuous One"; "all is full of being . . . no defect is there in it." Apparently he considered it unthinkable that any thing should come into being out of nothing or pass into nothing.
So he regarded reality as eternal—uncreated and imperishable. There is no empty space, "all is full of being," and so there is no possibility of motion. Reality was apparently a finite, spherical, motionless, continuous plenum, and change, movement and the very existence of ordinary discrete things illusory.
Zeno (?49o-42o B.C.) supplied the best known arguments in support of Eleatic monism. His famous paradoxes were intended to show the absurdities involved in the position of pluralism, that is the view that reality is not one but a multiplicity, a many. In opposition to the Pythagorean conception of reality as a multi plicity of spatial units, he argued that if so even a line must consist of an infinite number of points, and if each point has no magnitude then any thing must be infinitely small, but if the point has magnitude then each thing is infinitely great.
Melissus ( ?44o B.c.) modified the teaching of Parmenides to the extent of regarding reality as infinite. His contention was that if the real were finite it could only be bounded by empty space. Hence Parmenides' rejection of empty space really com mitted him to the view that reality is infinite. Similarly, he regarded the non-existence of empty space as a reason for the impossibility of the existence of a multiplicity of discrete things.
Being is one and immutable and can only be apprehended by thought. (See ELEATIC SCHOOL.) The arguments of Zeno and Melissus were largely directed against the views of Heraclitus, Anaxagoras and Empedocles.
Heraclitus (?54o-475 B.c.) held that fire is the primal matter. The naturalistic trend of thought is very marked in Heraclitus, as is evident from the following fragment. "This one order of all things was created by none of the gods, nor yet by any of man kind, but it ever was, and is, and shall be—eternal fire—ignited by measure and extinguished by measure." Matter as conceived by Heraclitus is always changing and always moving, though its movements often elude our observation.
The world "begins" as a mass of fire, some changing partly into water. The water changes partly into earth and partly into vapour. The vapour returns to fire. The earth changes back to water, and from water to vapour and thence to fire again. And then the cycle of changes begins all over again, each complete stage being marked by a mass of fire at the beginning and at its end. The greatest service rendered by Heraclitus consists in his insistence on what may be called universal law—all changes begin "by measure." As regularity was naturally regarded as a sign of intelligence, Heraclitus posited the existence of "universal reason" side by side with primal matter, or as part of it, and regarded it as the one thing that is permanent in the ceaseless flux of changes. Another idea for which Heraclitus is noteworthy is that of the struggle for existence, which he conceived to charac terize all things, and to be good for them.
Anaxagoras (?5oo-428 B.c.) held that originally there was not one kind of primal matter but a multiplicity of all sorts of parts or "seeds" of things. These were all mixed up in chaotic con fusion. But they were sorted out and arranged in an orderly manner by the "intelligence" or "reason" which pervades the uni verse. This reason is omniscient and omnipotent, but was still conceived by Anaxagoras in a semi-material fashion. This doc trine of the multiplicity of "seeds," through new combinations of which new things come into being, and by the separation of which they cease to be, paved the way for the atomic theory. The con ception of "mind" or "reason" as introducing order into things was subsequently adapted by Aristotle. Most important, per haps, is the fact that Anaxagoras went to Athens about 462 B.C. and so helped to transplant Ionian philosophy to the city of Pericles.