and declare everything to be in flux. In suggesting laws of recurrence and a reason in which what is common to many might be expressed, Heraclitus had opened the door into another region: had he passed through, his philosophy would have been greatly modified, for permanent forms would have forced themselves on his attention no less than shifting materials. Such a Heraclitus would have anticipated Plato; but the time for such a synthesis had not yet arrived.
At the opposite pole from immediacy lies intelligibility. To reduce phenomena to constant elements, as similar and simple as possible, and to conceive their union and separation to obey constant laws, is what a natural philosopher will inevitably do so soon as his interest is not merely to utter experience but to understand it. Democritus brought this scientific ideal to its ultimate expression. By including psychic existence in his atomic system, he indicated a problem which natural science has since practically abandoned but which it may some day be compelled to take up. The atoms of Democritus seem to us gross, even for chemistry, and their quality would have to undergo great transformation if they were to support intelligibly psychic being as well; but that very grossness and false simplicity had its merits, and science must be for ever grateful to the man who at its inception could so clearly formulate its mechanical ideal. That the world is not so in-
