I am currently finalising my first book on the ethics of partiality.

All of us have positive personal relationships that we value, especially with our family, friends, or colleagues. We see these engagements as giving us reasons that others do not have for certain actions and attitudes. We see ourselves as owing more to our children, spouse, and friends than to people who are completely unrelated to us. We feel joy and excitement when our intimates fare well and sadness and grief when they fare poorly. These instances of justified positive partiality – a special kind of concern affecting both our actions and our attitudes – have received a great deal of attention because they challenge an impersonal understanding of morality yet are a central part of human flourishing and often held to ground moral obligations.

However, we are also commonly caught up in personal relationships that are antagonistic and involve parties who do not value each other. The roots of such adversarial relationships are as diverse as those of their positive counterparts, ranging from competitive rivalries to histories of bullying or offence among colleagues or classmates. Enmity can emerge from disillusionment between romantic partners, estrangement among former friends, or mere passive-aggressive behaviour among neighbours.

But even though negative personal relationships are widespread, the scholarship on the ethics of partiality has virtually ignored them. It has focused exclusively on positive personal relationships, seeking to answer questions like: What do we owe ourselves, family, and friends? How extensive are these associative duties to act in certain ways in virtue of the special relationships in which we stand to our intimates? And what justifies these special duties?

The reality of human interaction, by contrast, is complex. Though positive personal relationships are important and central to our lives, negative ones are too. And our lives contain plenty of both. Indeed, our relationships can evolve over time: friends can become enemies, and enemies can become friends.

The Ethics of Enmity provides the first systematic and exhaustive treatment of negative partiality: the domain of what we owe to our adversaries, as opposed to what we owe to intimates like our family and friends. At a general level, The Ethics of Enmity will offer an understanding of what kinds of personal relationships give rise to negative partiality and why; the responses to adversaries called for by negative personal relationships; the elements that constitutive negative personal relationships, their termination, and their transition; the relation between positive partiality towards intimates and negative partiality towards adversaries; and the connection between negative partiality and areas that include the ethics of forgiveness, reactive attitudes, and defensive harm.

At a more specific level, this book will answer questions like: What do I owe an ex-partner with whom I have had a bad break-up or divorce? How ought I to behave towards a snide colleague who has it in for me just for the sake of it? Under what circumstances should I feel guilty about having ignored my passive-aggressive neighbour? What are the normative reasons for considerate behaviour do I have once a friendship of mine has become toxic, and what ought I to do about it?