ABSTRACT
The thesis of incommensurability is a philosophical doctrine of what D. Davidson calls radical conceptual relativism. According to Davidson's interpretation of the Quinean notion of conceptual schemes, a conceptual scheme is identical with a sentential language held to be true by its believers. Conceptual relativists believe that there are distinct conceptual schemes to schematize our experience such that meaning, truth, cross-language understanding and communication, and human perceptions of reality are relative to conceptual schemes. The notion of conceptual schemes and its underlying metaphysical dualism between scheme and content serve as the conceptual foundation of the thesis of incommensurability. Philosophically, the notion of conceptual schemes begins its intellectual life with Kant's transcendental philosophy. To answer his ingenious question of how experience is possible, Kant divides the mind into active and passive faculties, that is sensibility or unsynthesized a priori sensible intuitions of space and time on the one hand and understanding with endowed pure concepts or categories on the other.
