Reciprocity

To reciprocate is to return good in proportion to the good one has received, or to retaliate proportionately for harms. The central, contested philosophical issues surrounding reciprocity are whether reciprocity is a fundamental moral principle or a subsidiary one; how we are to measure fittingness and proportionality; and whether the norm of reciprocity requires that we reciprocate for all the goods we receive, or only for the ones we invite. While most philosophers believe that reciprocity is a subsidiary principle which is unproblematic only in the context of fully voluntary transactions, there are significant minority views on this matter.