Any description of the emergence of meaning in biological and artificial systems should be grounded on a framework that can make it possible to grasp the nature and dynamics of such processes. Here we take Peirce's pragmatic philosophy of sign, in association with Salthe's hierarchical structuralism, as a heuristically powerful basis for developing this conceptual framework. We formulate some questions which we regard as fundamental to a precise application of the notion of emergence in the context of investigations about semiotic systems.