HIPPO, Greek philosopher and natural scientist of the Ionian or physical school, was probably a contemporary of Archelaus and lived chiefly in Athens. Aristotle thought him unworthy of the name of philosopher. Hippo held that the principle of all things is moisture (TO vypnv) ; that fire develops from water, and from fire the material universe. His denial of all existence save that of things known through the senses led to his being classed among the "Atheists." The gods are merely men canonized by popular tradition. It is said that he composed his own epitaph, wherein he claims for himself a place in this company.
See Diels, Fragmente der Vorsokratiker, vol. i. (4th ed., 1922).