The scholarly literature on the evil eye converges on one word: envy. The belief's classic habitat is the face-to-face community of scarce goods, where one family's fat harvest is legible to neighbors whose harvest failed, and where good fortune is therefore dangerous to display. The eye that harms is the eye that covets; in many of the languages concerned the idiom says so directly, and the folk etiology adds that the possessor of the eye need not intend the harm, envy leaking out of a glance as it were involuntarily, which conveniently makes everyone a suspect and no one an accuser. Dundes's influential analysis pushed the pattern further, arguing that the underlying folk physics is liquid: the eye dries up what it strikes, milk in mothers and cattle, sap in crops, the bodily moisture of infants, wasting diseases being the eye's signature, and the counter-measures correspondingly wet, spitting above all.
Whatever one makes of the particular theory, the sociological function is well documented ethnographically: fear of the eye polices display, compels the fortunate to share, deflects praise, the compliment being instantly qualified, the beautiful child smudged with soot or given a slighting nickname, and supplies an explanation of misfortune that indicts a relationship rather than blind chance. The belief is thus less a superstition about optics than a folk theory of envy's destructiveness, expressed as an anatomy. Where inequality is visible and insurance absent, the evil eye is, in its way, functional social theory.