The endurance of homeopathy within parts of the medical profession is not primarily an empirical puzzle but ratheran epistemological fault line. While medicine, since the Enlightenment (late seventeenth century–early nineteenthcentury CE, when understood as a long-term cultural pro-cess), has gradually anchored itself in principles and mechanisms open to empirical scrutiny and causal explanation,homeopathy still operates on concepts formulated prior tothe discovery of microbes, pharmacological receptors, or theconservation of mass.