Friendship and love are considered by most people as necessary aspects of a good life and this idea transcends different cultures and times. They are considered by many psychologists to be genetic dispositions, hard-wired into our very essence and a necessary component for every human being to be able to to lead a good life. According to the kin selection theory, animals help close relatives more often than they help non relatives. In human society this is referred to as nepotism and cross cultural research shows that this behaviour is common everywhere.

The subject of friendship and love has been much discussed in ancient philosophy, but has been somewhat ignored in modern ethical theories. Michael Stocker argues that modern ethical theories can not account for the importance most of us attach to love and friendship. Stocker directs his criticism in particular at Kantian deontologies and consequentialist theories, such as act-utilitarianism and rule- utilitarianism.