were not distinguished from each other by any differences of quality. In point of quality they were homogeneous, or of the same kind; their differences are quantitative merely, that is to say they differed from each other in size, weight, figure, arrangement, agility of motion, these being mere quantitative differences; but they did not differ from each other in being hot or cold, luminous or dark, sweet or bitter, wet or dry, for these are qualitative distinctions. Such distinctions were held to have no reality in rerum natura; all objective reality and objective difference were reduced to quantity alone.
5. The atoms were thus closely analogous to the pure Being of Parmenides and the Eleatics. They were of one uniform quality, if, indeed, quality could be attributed to them at all. The distinction between the two schools, the Eleatic and the Atomic, was that while no differences, either qualitative or quantitative, had places in the pure Being of the Eleatics, the Atomic philosophers represented their primordial constituents as differing, as has been said, in size, shape, arrangement, &c. In like manner the Atomic school differed from Empedocles, who had attributed differences of quality to his four elements, fire, air, earth, and water. Empedocles had thought that this postulate was necessary in order to account for the changing phenomena of the universe. The Atomists were of opinion that these changes might be accounted for without any such postulate.
