The single theme that is most nearly the essential thread of Donald Davidson's entire philosophical output is this: to bring into coherent and plausible order all the categories by" which we understand the functional relationship between language and the world - primarily with regard to the effective success of practical life in cognition and action - without relying on the mediating role of theories, conceptual schemes, privileged philosophical doctrines, or other such tertia. Davidson himself says as much, for instance in the John Dewey lectures of 1989 (presented at Columbia University).