Image, diagram, and metaphor
It is far from implausible that some of C. S. Peirce’s other distinctions might eventually prove to be as heuristically fruitful as the distinction of icon, index, and symbol has proven itself to be. This distinction is based upon the relationship between a sign and its dynamical object, a relationship which constitutes the basis (or “ground”) of signification since it accounts for why anything is accorded the status of a sign. Anything functions <i>iconically</i> insofar as the basis of signification is an intrinsic relationship between the perceptible properties of a sign and its object. Anything functions <i>indexically</i> insofar as the basis of its signification is a causal connection, whereas anything functions <i>symbolically</i> insofar as this basis (or “ground”) is a disposition. These distinguishable functions are, more often than not, dynamically integrated in actual signs. They name not separate signs but distinct functions of irreducibly complex processes.