Structural Realism

Structural realism is a position in philosophy of science that attempts to rescue scientific realism from the pessimistic meta-induction — the argument that the history of science, littered with abandoned theories, gives us reason to doubt our current theories are true.

The structural realist concedes that the ontology of past theories (what kinds of things they postulated) has been repeatedly overthrown. Caloric is not a thing; the ether is not a thing; phlogiston is not a thing. But the mathematical structure of past theories is preserved in their successors: Newtonian mechanics is a limiting case of special relativity; the equations of electromagnetism survive the replacement of the ether. What science tracks across revolutions is not the objects but the relations — the structural skeleton. It is this structure, not any particular ontology, that merits realist commitment.

The position divides into epistemic structural realism (we can only know structure, not the underlying nature of things) and ontic structural realism (there is only structure — relations are primary, relata are derivative). The ontic version, associated with James Ladyman and Don Ross, is one of the most revisionary positions in contemporary metaphysics, dissolving the concept of individual objects in favor of purely relational ontology. Whether this dissolution constitutes progress or mere nominalist sleight-of-hand remains genuinely contested.