This study was supported by a generous fellowship at Wissenschaftskolleg zu Berlin. An early version of this paper was presented at the Tuesday Colloquium of Wissenschaftskolleg zu Berlin, April 2016. I wish to thank to all my colleagues (cohort 2015/2016) for their feedback and for giving me the opportunity to discuss my work. I am particularly grateful to Alex Drace-Francis for his useful comments and to James Christian Brown for carefully reading and rendering the paper more readable. I would also like to thank this journal's anonymous reviewers for their comments. Paul Lawrence kindly helped me with advice and suggestions regarding the structure of this paper.