The central concern of poststructuralism is the thinking of difference. In various formulations, principally Nietzschean, Marxist, feminist, or postcolonial, the poststructural purpose is to question the seemingly natural givens of identity. Metaphor's formal efficacy made it a touchstone for the structuralist and poststructuralist concern with the instability of meaning. The hope for a universally applicable science of signs gave way in the transition to poststructuralism. Poststructuralism's Hermetic bent avails itself of insight in Hillman's study of the poetic artifice of case histories, healing fictions. In a discussion of genre, Hillman distinguished the elements of a Saturnian discourse from those of a Hermetic one. Metaphor presented its speculative value at the turn of the twentieth century, increasingly asserting itself into the discourses of philosophy as the century unfolded. Ever the symptom, it encountered dissection at the hands of Anglo-American philosophy of language, and a characteristically more holistic treatment in hermeneutics and phenomenology, especially in their poststructural variants.