Poincaré’s Radical Ontology

I present an exegesis of Henri Poincaré’s metaphysical position in three key essays within his book The Value of Science. In doing so, I argue for three theses: (a) that Poincaré’s metaphysical position in these sources is incompatible with his metaphysical position in his earlier book Science and Hypothesis; (b) that the phenomenological relationism defended by Poincaré in these sources is not a form of structural realism but rather a structuralist form of empiricism and (by design) has no greater metaphysical commitments than constructive empiricism; and (c) that Poincaré holds in these sources that the existence of the external world is merely a convention. These theses serve to correct misconceptions about the consistency of Poincaré’s philosophical corpus, his positions on the realism-antirealism landscape, and the scope of his conventionalism.