The paper attempts to reconcile realism and constructivism (i) by endorsing an essentialist conception of the individuation of objects, (ii) by pointing to the conventional character of the essential/accidental distinction, (iii) by noticing that conventions may still leave room for the empirical investigation of essential properties, and (iv) by observing that despite this conventionality realism need not be derogated in any way. The final section points to some consequences for social ontology.