The biological entrance to this question is through natural selection and the ideas of Charles Darwin – the family structure preserves the genetic makeup and increases the chances of passing on the genes; therefore those families with the gene of family loyalty have flourished. Sociologically, we begin with Claude Levi-Strauss, whose anthropological theories posit family relationships as one of the identifying traits of any society – the power arrangement, the heredity order, and other such family features serve to identify the deeper social structures of power, dominance, and servitude. Families, relatives, kinship loyalties, etc. all stem from an essential social structure dictated by the society as a whole in which the family survives. A classic example from Shakespeare is King Lear – in which the complications grow from a confusion of family inheritance “rules” when Lear retires prematurely; Hamlet, to, can be analysed from Levi-Strauss’ view. In fact, a whole area of study in literature is built around the implications of family structures.