Chapter IV.—Heraclitus; His Universal Dogmatism; His Theory of Flux; Other Systems. But Heraclitus, a natural philosopher of Ephesus, surrendered himself to universal grief, condemning the ignorance of the entire of life, and of all men; nay, commiserating the (very) existence of mortals, for he asserted that he himself knew everything, whereas the rest of mankind nothing. But he also advanced statements almost in concert with Empedocles, saying that the originating principle of all things is discord and friendship, and that the Deity is a fire endued with intelligence, and that all things are borne one upon another, and never are at a standstill; and just as Empedocles, he affirmed that the entire locality about us is full of evil things, and that these evil things reach as far as the moon, being extended from the quarter situated around the earth, and that they do not advance further, inasmuch as the entire space above the moon is more pure. So also it seemed to Heraclitus. After these arose also other natural philosophers, whose opinions we have not deemed it necessary to declare, (inasmuch as) they present no diversity to those already specified. Since, however, upon the whole, a not inconsiderable school has sprung (from thence), and many natural philosophers subsequently have arisen from them, each advancing different accounts of the nature of the universe, it seems also to us advisable, that, explaining the philosophy that has come down by succession from Pythagoras, we should recur to the opinions entertained by those living after the time of Thales, and that, furnishing a narrative of these, we should approach the consideration of the ethical and logical philosophy which Socrates and Aristotle originated, the former ethical, and the latter logical.