“In the fifth century B.C., the physician Hippocrates was struggling with the nature of disease. He had been trained to practice medicine in a world where the divine suffused everything. Doctors were also priests, and they treated the sick by sending them for a night’s vigil in one of the temples of Aesculapius, god of healing. Perhaps the sacred serpents that lived in the temple would lick the patient’s wounds and miraculously heal them; or maybe the god would send a dream explaining how the illness should be treated; or, Aesculapius himself might even appear to carry out the cure. In this world, Hippocrates was an outlier. He did not think that diseases were caused by angry deities, nor that they needed to be cured by a benevolent one. “I do not believe,” he wrote in his treatise about epilepsy, long thought to be a holy affliction sent directly from the gods, “that the ‘Sacred Disease’ is any more divine or sacred than any other disease, but, on the contrary, has specific characteristics and a definite cause . . . It is my opinion that those who first called this disease ‘sacred’ were the sort of people we now call witch-doctors, faith-healers, quacks and charlatans . . . By invoking a divine element they were able to screen their own failure to give suitable treatments.” Instead of invoking the gods, Hippocrates looked to the visible world, searching for both “definite causes” and “suitable treatments” in nature itself. His investigations led him to formulate an entirely secular theory of disease.”…"He was not doing science as we would understand it; he was philosophizing about nature, attempting to reason his way into a closed system that he could not observe. But Hippocrates and his followers were at least attempting to find natural factors that would help explain the natural world. So the Hippocratic Corpus—some sixty medical texts, collected by his students and followers, that neither blame nor invoke the gods—is the first written record of a scientific endeavor. "
(from “The Well-Educated Mind: A Guide to the Classical Education You Never Had (Updated and Expanded)” by Susan Wise Bauer)