 Theories of justice can then be distinguished according to the relative weight they attach to procedures and substantive outcomes. Some theories are purely procedural in form. Robert Nozick distinguished between historical theories of justice, end-state theories, and patterned theories in order to defend the first against the second and third (Nozick 1974). An end-state theory defines justice in terms of some overall property of a distribution (of resources, welfare, etc.) – for example whether it is egalitarian, or whether the lowest position in the distribution is as high as it can be, as Rawls’ difference principle requires. A patterned theory looks at whether what each receives as part of a distribution matches some individual feature such as their desert or their need. By contrast, an historical theory asks about the process by which the final outcome has arisen. In Nozick’s particular case, a distribution of resources is said to be just if everyone within its scope is entitled to what they now own, having acquired it by legitimate means – such as voluntary contract or gift – from someone who was also entitled to have it, leading back eventually to a just act of acquisition – such as labouring on a plot of land – that gave the first owner his valid title. The shape of the final distribution is irrelevant: according to Nozick, justice is entirely a matter of the sequence of prior events that created it (for critical assessments of Nozick’s position, see Paul 1982, Wolff 1991, Cohen 1995, chs. 1–2).