 But what tasks are necessary? Some, as we have seen, point to the production of “presumptively beneficial public goods”, goods that anyone would want and which require social co-operation to produce (Klosko 1991). Other views are more expansive. Finnis, for example, believes that law must provide a comprehensive framework for realizing a list of supposedly self-evident values including life, knowledge, play and religion (Finnis 1979: 81–97, 154–156). In between, we find a range of nuanced intermediate positions (see, for example, Copp 1999 and Perry 2012). An influential intermediate position ties political authority to the realm of justice and grounds obedience in a natural duty. According to John Rawls,