Shamanistic, religious, and empirical approaches to healing seem to be universal aspects of the history of medicine. Where Greek medicine appears to be unique is in the development of a body of medical theory associated with natural philosophy, that is, a strong secular tradition of free enquiry, or what would now be called science. Scholars have sug- gested that the fundamental difference between Greek and Chinese thought was the competitiveness of early Greek political and intel- lectual life. Whereas Chinese thinkers sought consensus, Greek thinkers openly criticized their teachers, rivals, and peers. Unlike previous civilizations, the Greeks were not primarily organized around agricul- ture and a strong central government or priesthood. The city-state became their unit of organization and, because Greece was relatively overpopulated in relation to cultivatable land, trade, colonization, and industry were encouraged.
The earliest Greek natural philosophers were profoundly interested in the natural world and the search for explanations of how and why the world and human beings came to be formed and organized as they were. Natural philosophy developed ﬁrst, not in the Athens of Socrates, Plato, and Aristotle, but on the Aegean fringes of the mainland of Asia Minor. By the sixth-century B.C.E., Greek philosophers were attempting to explain the workings of the universe in terms of everyday experience and by analogies with craft processes rather than divine interventions and supernatural agents. Many of the earliest Greek philosophers are known only through a few fragments of their work, but enough has survived to reveal their ingenious theories as the seed crystals that were to stimulate the subsequent evolution of Western physics, astronomy, biology, and medicine.
Pythagoras of Samos (ca. 530 B.C.E.) is said to have been the ﬁrst Greek philosopher with a special interest in medical subjects. Although the Pythagorean concept of a universe composed of opposite qualities is reminiscent of Chinese yin-yang philosophy, the Pythagorean ap- proach was apparently inspired by mathematical inquiries. Just as num- bers formed the two categories, ‘‘odd’’ and ‘‘even,’’ so could all things be divided into pairs of opposites. The harmony, or proper balance of pairs of qualities, such as hot and cold, moist and dry, was especially important in matters of health and disease.
Although the medical theories of Alcmaeon of Croton (ca. 500 B.C.E.) have much in common with those of Pythagoras, the exact rela- tionship between them is uncertain. Both Alcmaeon and Pythagoras believed that pairs of opposites were the ﬁrst principles of exis- tence. Health, according to Alcmaeon, was a harmonious blending of each of the qualities with its appropriate opposite, such as moist and dry, cold and hot, bitter and sweet. Disease occurs when one member of a pair appears in excess; an excess of heat causes fever, an excess of cold causes chills. The idea that the systematic dissection of animals would provide a means of understanding the nature of human beings was attributed to Alcmaeon. Despite the loss of most of his writings, Alcmaeon was one of the ﬁrst physician-philosophers to exert a signiﬁcant inﬂuence on the course of Greek medical and scientiﬁc thought.
A paradoxical blend of philosophy and mysticism is part of the legacy of Empedocles (ca. 500–430 B.C.E.). Echoing themes common to shamanism, Empedocles boasted that he could heal the sick, rejuvenate the aged, raise the dead, and control wind and weather. Numerous references to him in later medical writings suggest great fame and success as a healer, but it was his theory of the four elements that became a major theme in the history of medicine. According to Empedocles, all things were composed of mixtures of four primary and eternal ele- ments: air, earth, water, and ﬁre. Changes and transformations in the cosmos and the human body were simply reﬂections of the mixing and unmixing of the eternal elements.