Why were there humors at all? Humors are a peculiar concept and many medical models in ancient societies conceived the body in quite other terms – nor are corporeal fluids an obvious principle or explanans of first resort. The signs of illness and health are not primarily liquid, and bodies, human or animal, though they contain liquids, hold also many solids. Yet most Greek theories of health and disease persistently propound humors, and foremost among them blood.
For early Greeks, blood symbolized life, more so than did other liquids, so that spirits who drank it regained for a time some semblance of life (Odyssey 11.96, 147–149; Aesch. Cho. 578; Soph. Electra 785–786). By a very widespread, and ancient (or even prehistoric), synecdoche, blood was the substance of life, whose total loss, as in sacrifice, meant death. The palaeolithic and neolithic use of ruddle in funerary contexts suggests the same, as do also texts in the Hebrew Torah, and even Empedocles 31 B100 DK (on breathing).
But why would blood become foremost among humors? The clue may lie in a proto-humoral theory implicit in early Greek literature. Zeus of Olympos (Iliad 19.105), Glaukos of Lykia (6.211), Aineias of Troy (20.241), and Telemachos of Ithaca (Odyssey 4.611, 16.300) all have a descent and heritage “of blood.” The same metaphor was deployed by Pindar, Aeschylus, Sophocles, and Herodotos – and indeed widely in Greek and Latin literature.
What were they thinking? What has blood to do with heritage? It is a most peculiar metaphor – despite its reach even into modern European languages – and yet it seems so “natural” that scholars have been almost entirely silent. These archaic Greek “blood-lines” were usually paternal, thus ruling out menstrual blood as the tenor of the metaphor. Nevertheless, some “blood-lines” were maternal (Aesch. Seven 141–144; Eur. Suppl. 1035), showing that the metaphorical blood was not understood as a euphemism for “seed,” for which there is anyway no parallel. At least once, even animals seem to have “blood heritage” (Aesch., Suppl. 225–226).
So, how can we explain this peculiar metaphor? Parallels are lacking from Egyptian, Hebrew, Persian, and Sanskrit – but are known in Mesopotamia. No plausible source for “blood heritage” exists in Greek thought, but Sumerian (KAR 4) and Assyrian myth (Atraá¸«asÄ«s I.204–217, 221–243; EnÅ«ma eliš IV.32, VI.5–8, 31–32) told how the gods created people from divine blood. Likewise, the ancient Semitic verb “to live” is used only of creatures with blood. West Asiatic elements in early Greek culture are widespread enough to be undeniable. Elements for which common heritage or independent invention is impossible include, inter alia, the alphabet (and the names of most of its letters), the images perceived as constellations (both on and off the ecliptic), the techniques of iron-working, and numerous names for plants and products imported from those lands, which lack any plausible Indo-European etymology.
Thus the notion that blood not only “was” the life of an individual, but also mediated life through heritage, entered Greek thought from West Asia. “Blood heritage” meant the inheriting of life, from parents, not via blood, but as manifest in blood.
Another influence on blood-theories was phlebotomy, for which the earliest Greek evidence is Herakleitos 22 B58 DK (Hippolytos, Ref. 9.10), or the Peytel aryballos (of ca 475 bce): the practice may be Scythian (Airs, Waters, Places §22, Littré 2.78), and is definitely neither Egyptian nor Mesopotamian. A third contribution was the Egyptian theory that disease arose when decay entered the “blood-tubes” (mtw). The concoction of these components seeded the Greek propensity to see liquids as the media of health and disease, with blood at the center.
I will also speculate on the etymology for αἵμα (agreed by etymologists to be non-Indo-European), and discuss the long dark shadow of this archaic synecdoche on medieval and modern thought.