In this essay, "Der Geisterseher" is put in relation to a philosophy of love of Platonic derivation elaborated by Schiller in several instances of his production, as, for example, in "Theosophie des Julius". Here, love is seen as a principle of resistance to the mechanism of some radical versions of French illuminism (La Mettrie). Affectivity appears as a principle of interdependence among every existing thing, in compliance with the speculation of English sensualism. An account is given of the gradual passage, as in "Der Geisterseher", from a metaphysic of passions as the unity between nature and spirit, to the evocation of a critical rationality, sustained by the awareness of the limits of reason.