Legal positivism dominates in the debate between it and natural law, but close attention to the work of Thomas Hobbes -- the "founder" of the positivist tradition -- reveals a version of anti-positivism with the potential to change the contours of that debate. Hobbes's account of law ties law to legitimacy through the legal constraints of the rule of law. Legal order is essential to maintaining the order of civil society; and the institutions of legal order are structured in such (...) a way that government in accordance with the rule of law is intrinsically legitimate. I focus on Hobbes's neglected catalogue of the laws of nature. Only the first group gets much attention. Its function is to facilitate exit from the state of nature, an exit which Hobbes seems to make impossible. The second group sets out the moral psychology of both legislators and subjects necessary to sustain a properly functioning legal order. The third sets out the formal institutional requirements of such an order. The second and third groups show Hobbes not concerned with solving an insoluble problem of exit from the state of nature but with the construction of legitimate order. Because a sovereign is by definition one who governs through law, Hobbes's absolutism is constrained. Government in accordance with the rule of law is government subject to the moral constraints of the institutions of legal order. (shrink)