First Online: 13 February 2014This article provides a explanatory account of a central class of moral rights; their normative grounding, the conditions for their possession and forfeiture, and their moral stringency. It argues that interpersonal rights against harm and rights to assistance are best understood as arising from reciprocity relations between moral agents. The account has significant advantages compared with rivals such as the interest theory of rights. By explaining the differential enforceability of rights against harm and rights to assistance, the reciprocity theory helps to refute an argument made by Cecile Fabre that the poor may have a justification for engaging in war against the affluent to compel them to fulfil their...