On the Logic of Constitutive Rules

The paper proposes a logical systematization of the notion of countsas which is grounded on a very simple intuition about what counts-as statements actually mean, i.e., forms of classification. Moving from this analytical thesis the paper disentangles three semantically different readings of statements of the type X counts as Y in context C, from the weaker notion of contextual classification to the stronger notion of constitutive rule. These many ways in which counts-as can be said are then formally addressed by making use of modal logic techniques. The resulting framework allows for a formal characterization of all the involved notions and their reciprocal logical relationships.