  Again: How could such fundamental questions as “Should we have law at all?” be “given shape” by the positivist thesis that law’s existence and content depends only on social facts? Does not Green’s claim invert the reasonable order of inquiry and reflection?  Basic human needs and circumstances powerfully suggest to people in virtually all times and places that they should make and uphold some norms of the kind we call law, norms which will depend directly and for the most part on social facts such as custom, authoritative rule-making, and adjudication. Legal philosophy retraces and clarifies, critically, that elemental practical reasoning, somewhat as Hart did in Hart 1961, where he constructs a descriptive-explanatory account of law (i.e., refines his and our concept or understanding of law) by explaining how rules differ from habits, how powers have different functions and social value from obligations and so are not aptly reducible to obligations (and so also why power-conferring rules are distinct from duty-imposing rules), and how “primary” rules for outlawing gross violence, theft and fraud need, by reason of their lack of certainty in content and application and their immobility, to be supplemented by “secondary” rules of recognition, adjudication and change, the remedial supplementation that shifts a society into the domain and rule of law and legal system. May not those elements in Hart’s book be taken as an instance of natural law legal theory done in a primarily descriptive (rather than primarily justificatory) mode, and with incomplete scrutiny of the resources of practical reason, resources being drawn upon by the whole explanatory general description of law? Does not Hart’s description, despite its incompleteness, work as well as it does precisely because it disinters some elementary justifications conceived and put to use by the people whose activities provide the material for the descriptions?  Does he not share the deep methodology of Aristotle and the natural law tradition (Finnis 2003) in making his identification of what law is (of “the concept of law”) depend upon his account of why law is a reasonable response to common human needs?