This article argues that the basic notions and assumptions underlying H.L.A. Hart's theory of legal positivism imply a different plausible conclusion from the one he arrives at, which is that law and morality are logically separate. Hart has argued that the ability of a legal system to be sustained in principles is necessary for it to be valid. In his criticism of John Austin, he argues that in the absence of primary and secondary rules, the absolute sovereign will not provide a basis for a valid legal system because of the uncertainty in the period of interregnum between when a sovereign dies and when another is installed. However, the plausible ground for the acceptance of some procedures or criteria from an internal point of view--that is, in order for the general obedience of the laws of the system--is that the procedures are justifiably believed to yield with high probability good laws that most people will accept impartially as justifiable reasons for action and guides for conduct. But if there are bad laws that are inadvertently engendered by the accepted procedures, there are in principles built-in mechanisms in the system to rectify the evil laws: this, in part, is the basis for its inherent goodness and acceptance.