Vengeance is generally accompanied by the moral emotion of resentment and indignation, which are also natural psychological reactions. We can and do give these emotions cognitive content, inasmuch as they have developed and matured over time with culture, but they are primitive. They arise when an individual suffers a non-trivial injury that was inflicted without excuse or justification. Among other injuries suffered, the harm done discounts the value we hold of ourselves as human beings, so that when this discounting (the crime or a substantial tort) occurs and we react defensively; our worth as an individual feels threatened. We hope then to impose punishment. Forgiveness comes later, if ever. Though it is owed to no one, it seems to...