The family is not merely an affective network or a contract: it is a social institution. As such, it is an object of law whose understanding requires recourse to legal thought. This is no easy task, since there are multiple legal bodies of knowledge about the family, and this knowledge resists both theorization and systematization. It remains nonetheless an indispensable task, as ignorance of this legal corpus leads to numerous abstractions and misconceptions. What sort of philosophy of the family would be able to account for these multiple forms of juridical knowledge, all the while respecting the complexity of its object? It would have to be a philosophy that was both social and institutionalist, one that draws on this legal corpus and relates it to wider social and political concerns.