Hippon (flourished c. 450 bc, southern Italy?) was a philosopher who revived the belief of the 6th-century philosopher Thales that the world originated from water or moisture. He held that fire first originated from water and that these two, operating as contrary forces, produced the physical cosmos. But he was more especially concerned with medicine and physiology, advancing the theory that disease and death were due to the drying up of the natural moisture in the body.