 To give a silly example, not everyone enjoys the sight of (particularly, white) socks in sandals. In our society, the sight of socks in sandals is something individuals have to endure because it is considered to be within the rights of the owners of white socks that they can wear them in public, in sandals or in other types of shoes. It is easy, however, to imagine societies that define the rights of sock-owners differently and value the tastes of those who are bothered by the blight of socks in sandals more highly. Indeed, even in modern liberal societies social norms regulate what is decent to wear in public. Since a good’s degree of excludability depends in part on property rights, and what property rights entail may differ between societies and, within societies, may change over time, a good’s excludability may differ between societies and change over time. 