Given a theory – e.g., in mathematics, theology, physics, sociology, political theory – what is it for the objects of that theory to be identical? Not all true theories give the same answer: it can depend on the objects of the theory. The logic of identity, as current research stands, is largely confined to the standard framework of classical logic. Non-classical logics have proven to be important in philosophy, and they are promising for related disciplines. What we lack, as current research stands, are natural, simple, and widely applicable accounts of identity for the family of non-classical frameworks. This one-day Arché workshop will explore the prospects for non-classical logical approaches to identity and their possible applications.