In the context of the Centre, Ulman Lindenberger intends to contribute to the perspectives of psychometrics and lifespan psychology on human cognitive abilities. Such a contribution entails an emphasis on methodology, understood here as the interface between psychological theory and statistical methods. Issues of reliability, validity, and stability play an important role in methodology. Discussions within psychology about the ontological status of human cognitive abilities might show resemblances and differences to discussions in neighbouring fields that are worth exploring.