In psychiatry there is no sharp boundary between the normal and the pathological. Although clear cases abound, it is often indeterminate whether a particular condition does or does not qualify as a mental disorder. For example, definitions of subthreshold disorders and of the prodromal stages of diseases are notoriously contentious.

Edited by Geert Keil , Professor of Philosophy, Department of Philosophy, Humboldt University, Berlin

Lara Keuck , Research Fellow, Humboldt University Berlin, Department of History

Rico Hauswald , Research Fellow, Dresden University of Technology, Department of Philosophy

Geert Keil is Professor of Philosophy at Humboldt-Universität Berlin. He studied philosophy, linguistics and German literature at the Universities of Bochum and Hamburg. In 1991, he received his PhD with a book on philosophical naturalism. In 1999 he received his Habilitation (second dissertation) with a book on causation and agency. Awarded with a Feodor Lynen scholarship of the Humboldt Foundation and a Heisenberg scholarship of the German Research Foundation (DFG), he was a visiting scholar at the Universities of Trondheim, Stanford and Basel. From 2005 to 2010 he held a chair in theoretical philosophy at RWTH Aachen University. He co-directed the research project "Dealing Reasonably with Blurred Boundaries" (2009-2013). His main areas of research are the philosophy of mind and action, philosophy of language, epistemology and metaphysics. Lara Keuck is a Research Scholar at the Department of History at Humboldt University Berlin and a 'Society in Science - Branco Weiss Fellow' of ETH Zurich. Her research interests lie in the history and philosophy of the biomedical sciences, broadly construed. She has published on epistemological issues surrounding the classification and modelling of mental disorders in History and Philosophy of the Life Sciences, Medicine Studies, Journal of Medical Ethics, and Studies in History and Philosophy of Biological and Biomedical Sciences. In 2012, she was awarded the Prize for Philosophy in Psychiatry of the German Association of Psychiatry, Psychotherapy and Psychosomatics (DGPPN). Rico Hauswald studied philosophy and sociology in Dresden, Germany, and Fribourg, Switzerland. In 2013, he did his PhD at Humboldt University of Berlin with a thesis about the classification of people in the social and medical sciences. He is currently a research fellow at Dresden University of Technology. His areas of specialization include the philosophy of medicine, general philosophy of science, social epistemology, and social ontology. His recent publications include "The Ontology of Interactive Kinds" (forthcoming in the Journal of Social Ontology), the monograph Soziale Pluralitäten (Münster: Mentis 2014), and the volume Warum ist überhaupt etwas und nicht vielmehr nichts? (Hamburg: Meiner 2013, co-edited with D. Schubbe and J. Lemanski).