The natural law theory holds that along with the positive law there exist certain ideal principles or value to which the positive law should correspond if it is to be regarded as a genuine law. Thus, while positivism holds that to be a valid law all that is required is that it should issue from a competent legislator after following the prescribed process, the natural law theory requires in addition that such a law, to be valid, must conform to some ideal principle (which may emanate from morality, reason, God or some other such source). The Hart — Fuller ‘debate’ illustrated the opposing points of view of positivism and natural law, particularly in the context of Nazi Laws. Mention has been made of this debate in the author’s book’ Law in the Scientific Era’, at page 65 of that book. The history of the ‘debate’ is mentioned in the Revised Edition of Fuller’s book ‘The Morality of Law’ (in chap ....