A closer examination is needed to show us by what causes the current of Greek thought was swayed. The great religious movement of the sixth and fifth centuries—chiefly represented for us by the names of Pythagoras, Aeschylus, and Pindar—would in all probability have entirely won over the educated classes, and given definiteness to the half-articulate utterances of popular tradition, had it not been arrested prematurely by the development of physical speculation. We showed in the first chapter that Greek philosophy in its earliest stages was entirely materialistic. It differed, indeed, from modern materialism in holding that the soul, or seat of conscious life, is an entity distinct from the body; but the distinction was one between a grosser and a finer matter, or else between a simpler and a more complex arrangement of the same matter, not between an extended and an indivisible substance. Whatever theories, then, were entertained with respect to the one would inevitably come to be entertained also with respect to the other. Now, with the exception of the Eleates, who denied the reality of change and separation altogether, every school agreed in teaching that all particular bodies are formed either by differentiation or by decomposition and recomposition out of the same primordial elements. From this it followed, as a natural consequence, that, although the whole mass of matter was eternal, each particular aggregate of matter must perish in order to release the elements required for the formation of new aggregates. It is obvious that, assuming the soul to be material, its immortality was irreconcilable with such a doctrine as this. A combination of four elements and two conflicting forces, such as Empedocles supposed the human mind to be, could not possibly outlast the organism in which it was enclosed; and if Empedocles himself, by an inconsistency not uncommon with men of genius, refused to draw the only legitimate conclusion from his own principles, the discrepancy could not fail to force itself on his successors. Still more fatal to the belief in a continuance of personal identity after death was the theory put forward by Diogenes of Apollonia, that there is really no personal identity even in life—that consciousness is only maintained by a perpetual inhalation of the vital air in which all reason resides. The soul very literally left the body with the last breath, and had a poor chance of holding together afterwards, especially, as the wits observed, if a high wind happened to be blowing at the time.