Abstract
Abstract It is a necessary condition for recognising change that there is a yardstick against which the change can be perceived. The same applies to changes that philosophical concepts undergo. This paper delineates standards for recognising conceptual change that meet the requirements of conscientious history of philosophy. More particularly, we want to argue for the need of what we will call non-textual standards. These are features of the world of experience that must be assumed to be shared between us and the historical authors we study. While they must be used in tandem with the recognised contextual standards of conceptual change, we will argue that without recourse to at least some non-textual standards, important kinds of conceptual change will remain inexplicable.