In a 1973 article, H.L.A. Hart says the following about Jeremy Bentham's achievements in the philosophy of law:
Bentham was certainly not the first to define law as a command: Hobbes, for example, had anticipated him in that, and even the despised Blackstone's definition of municipal law was in terms of command. But Bentham differed from Hobbes and, as far as I know, from all previous social theorists in insisting that we must not so define our terms in legal or political theory as to make the practical conclusions which we favour follow from them. Such definitions have been aptly called ‘persuasive definitions’ and among Bentham's many claims to be an innovator none is better founded nor, I think, more important than his insistence on a precise and so far as possible a morally neutral vocabulary for use in the discussion of law and politics. This insistence, though it may seem a merely linguistic matter, was the very centre, and I would say the sane and healthy centre, of the legal positivism of which Bentham may be regarded as the founder. It accounts for many important themes in his general theory including the form of his own definition of law. The terms that Bentham uses to define law are all flatly descriptive and normatively neutral. (1973, 28)