Beginning with the discussion of a fundmental defect in China's legal science, this thesis first makes a research into the existence of law, which is essential to the understanding of the tradition of legal positivism. Then it interprets the legal theories of John Austin, Jeremy Bentham, Hans Kelsen and H.L.A. Hart, the four leading legal philosophers advocating legal positivism, and tries to gain an insight into their interpretation of the existence of law. Accordingly, this thesis is an outline study of the existence of law, which will prove to be very helpful in making in-depth studies of it.The thesis mainly studies the basic components of the existence of law, namely the philosophical ideas backing it, its structure and its social and political backgrounds, interprets the legal theories of John Austin, Jeremy Bentham, Hans Kelsen and H.L.A. Hart, and points out the merits and demerits of their theories. Generally, John Austin and Jeremy Bentham believed in the political nature of the existence of law, Kelsen's theory is considered a scientifically understood type of legal positivism, and Hart attempted to interpret the existence of law with the tools of analytic, and especially linguistic, philosophy, which marked a fundamental change in the existence of law.Finally a conclusion is drawn that John Austin is still worthy of our attention since the existence of law still has its political nature today, and that Kelsen, who denied the existence of politics in law, and Hart, who replaced commands with rules, did not really surpass Austin. |