 Contrary to in re structuralists, Poincaré’s structures are not ontologically but rather epistemically dependent on their instances. The faculty capable of creating the general concept of a group or of indefinite iteration is the expression of a form of our understanding “prior to all experience” (Poincaré 1898: 41). He defends a kind of constructive epistemological Platonism or anti-nominalism (Linnebo 2011), in which intuition is a cognitive faculty used to grasp from series of imagined sensations or concrete iterations the general structure. This is the solution that explains Folina’s characterization of Poincaré, which at first sight seems inconsistent, as an ante-rem structuralist and as an anti-realist with respect to mathematical objects (Folina 2020). The structure is not itself a position in a meta-structure, but the psycho-physiological procedure is the way in which we know of its existence in our mind. Poincaré uses it as a metamathematical “instrument which serves not to represents things to ourselves, but to reason” upon the psycho-physiological genesis of real actions with imagined sensations (Poincaré 1898: 41). The genesis of geometry is based on an epistemological process founded on previous classifications, carried out as a relationship between a structure as norm of invariance and “conventionally” adapted systems as instantiations and exemplifications of these norms.