Plutarch speculated on divination on the basis of his own Delphic, priestly experience. His account of a Pythia’s death through disrespect of the rules of oracular consultation is that of a man involved in ritual knowledge and duties. His Middle-Platonic critical examination of philosophical theories partly relies on rite and piety as constituents of tradition. Ritual concern and philosophical training are thus closely linked in producing a dynamical understanding of divination for which Plutarch’s attempt at sketching a general theory of signs and divine manifestations provides an example. Pursuing of philosophical Truth may be considered as the highest form of hosiotes because of the light it shades on ritual enactment. In the new garb of the philosopher-priest, Plutarch was acting for the accomplishment of ancestral piety.