 Most conceptions of the common good define a form of practical reasoning that fits the model of solidarity. Many social relationships require a form of solidarity among those who stand in the relationship. Solidarity here basically involves one person giving a certain subset of the interests of another person a status in her reasoning that is analogous to the status that she gives to her own interests in her reasoning (see, e.g., Aristotle NE 1166a1–33). For example, if my friend needs a place to sleep tonight, friendship requires that I should offer him my couch. I have to do this because friendship requires that I reason about events that affect my friend’s basic interests as if these events were affecting my own basic interests in a similar way. A conception of the common good typically requires citizens to maintain certain facilities because these facilities serve certain common interests. So when citizens reason as the conception requires, they effectively give the interests of their fellow citizens a status in their reasoning that is analogous to the status that they give to their own interests in their reasoning.