Abstract

I propose to sketch and compare the "picture theories" of Hermann von Helmholtz and Heinrich Hertz. These semiotic conceptions of scientific knowledge are forerunners of the now prevailing semantic views of scientific theories in philosophy of science, and my intent is to bring out the respective main features that either proved to be influential or, as such, retained in contemporary formal approaches to the semantics of physical theories. For our purposes, "picture theories" can be characterized as conceptions that take as a departure the fact that scientific theories are embodied in a system of signs and involve a systematic treatment of the relation that obtains between the semiotic system and the world. Essentially, such a theory will have in its core an answer to the question: "What does it take for a picture to be a picture of something?" In concludion, I outline a filiation between Helmholtz, Hertz and Carnap pertaining to the question of monomorphism or categoricity in the general semantics of physical theories.