Here we try to sustain the conception of scientific knowledge, alternative to the realistic, known as conceptual relativism, which consists in that physical theories give us a conceptualization of the world in certain mode, from the perspective of the conceptual frameworks of theories and, thus, in a manner relative and dependent of the theory adopted or constructed. The aim is to show that this conceptualist stance of physical theories is plausible, coherent and no trivial. In order to get that aim we expose, contrast and discuss the epistemological, ontological and semantics theses of realism as well those theses of the conceptualism.