During an interview that was part of my scholarship application, a referee for the Studienstiftung asked me which door I intended my dissertation project—which eventually grew into this book—to open. Off the top of my head, and probably fueled by a mild panic, I replied that I would rather like to close a door than to open a new one. In the course of the PhD process I learned that the closing of doors, sometimes, can feel like an impossibly hard thing to do and may take all the courage one can muster. So let’s hope this particular door will stay shut.
I wouldn’t have finished this book were it not for the support and advice of a number of people. My most heartfelt thanks go to my thesis supervisor, Gerhard Ernst, for his continuous encouragement and countless patient reminders that I, too, can be a philosopher. Also, I am very grateful to Mechthild Habermann, Geert Keil, and Rosario LaSala for their willingness to act as further members of my dissertation committee.
My former colleagues in Erlangen, the regular participants of our weekly Oberseminar (especially Dorothee Bleisch, Sanja Dembić, Sebastian Schmidt, and Konstantin Weber), and the students of two courses on vagueness I taught during my time as a PhD student were extremely helpful in shaping my views on the topic of this book, and provided a friendly and appreciative atmosphere. I am particularly grateful to Steffen Lesle for his down-to-earthness, integrity, and the willingness to have many, many cups of coffee with me while patiently listening to my babble about my newest cinematic discoveries (and, occasionally, while discussing philosophy).
Furthermore, I would like to thank Christian Nimtz, Fabian Hundertmark, Steven Kindley and the regular participants of the Bielefeld research seminar in Theoretical Philosophy for numerous instructive discussions. Diana Raffman kindly agreed to supervise my research stay at the University of Toronto in 2014, and a generous scholarship provided by the Studienstiftung des Deutschen Volkes enabled both said research stay and three years of largely uninterrupted work on my dissertation.
Finally, I would like to thank Michael Kienecker of the mentis publishing house for his editorial support. And Kai, for far too many things than would fit on this page.