I am grateful to Mark Berlin for his generous review of Unconscionable Crimes. One aim of the book, as Berlin notes, is to demonstrate the contributions philosophers can make to the interdisciplinary study of mass atrocities. Central to Berlin’s review are questions about who stands in need of such a demonstration and about how readers occupying different disciplinary and institutional positions might take up the book’s conclusions.

Regarding the first type of question, Unconscionable Crimes seeks to address audiences both within and outside of philosophy. Its strategy for doing so differs slightly in each case. For readers with a background in philosophy, the book works by situating its account of moral, legal, and social norms within the history of philosophical debates about the sources, grounds, and varieties of norms. For readers approaching the book from outside philosophy, the theoretical focus on explanatory and preventive accounts of mass atrocity provides common ground.

Some of the book’s arguments address both audiences on equal terms. Historians, sociologists, and political scientists have all been inclined to include claims of “norm inversion” or the disappearance of norms in their accounts of mass atrocity. Moral philosophers have sometimes embraced such claims while pursuing meta-ethical objectives. Unconscionable Crimes seeks to show that such claims typically lack both conceptual precision and empirical support. But some of the book’s background assumptions about how we should think about norms do differ from those prevailing in certain other disciplines. I argue, for example, that norms can be approached from the practical point of view; that is, the point of view of individuals deliberating about action. This is an approach familiar to philosophers but less intuitive to scholars working in sociology and anthropology. I am not certain whether even extensive engagement with the methodological assumptions current in those fields would narrow the gap significantly.

Regarding the second type of question, about how various readers might take up the book’s key claims, I am grateful for the chance to offer additional thoughts. To start, I hope scholars and practitioners working in various fields related to mass atrocity will be motivated to reflect on the norms that govern their own professional activities. Whether tasked with monitoring incitement, documenting conflict-related sexual violence, or coordinating with law enforcement and military personnel on the protection of minorities, professionals in this field regularly face significant moral and legal challenges. The analysis of norms in Unconscionable Crimes can sharpen individual and institutional responses to those challenges.

Second, I hope this book will prompt scholars and practitioners from many different backgrounds to attend more closely to the normative dimensions of large-scale crimes. Normative beliefs and attitudes are often said to be “inside the head” and so too difficult to study. Unconscionable Crimes shows that, by paying careful attention to the words and deliberations of individuals who have lived through atrocities, it is possible to make such an investigation. More than this, the book shows that attention to norms is essential for explaining, and preventing, large-scale crimes.