H. L. A. Hart was probably the most influential writer in the modern school of analytical jurisprudence,[1][2][3] though its history goes back at least to Jeremy Bentham.
Indeed, it was the analytical jurists who first pointed out that legal formalism is fundamentally mistaken as a theory of law.
Analytic, or 'clarificatory' jurisprudence uses a neutral point of view and descriptive language when referring to the aspects of legal systems.
David Hume famously argued in A Treatise of Human Nature that people invariably slip between describing that the world is a certain way to saying therefore we ought to conclude on a particular course of action.
Legal positivism is the dominant theory, although there are a growing number of critics, who offer their own interpretations.