 The study of particular rights is primarily an investigation into how such categories and sub-categories overlap. There has been much discussion, for example, of whether human rights are natural rights, whether the right to privacy is a legal right, and whether the legal right to life is a forfeitable right. (For the central jurisprudential debate over the relation between legal and moral rights, see  legal positivism,  natural law theories, and  the nature of law.)  Sometimes theorists will also do analytical work on a single subcategory: for example, Steiner (2013) questions whether inalienable or unwaivable rights are logically possible, and Andersson (2013) discusses who moral rightholders are.