In this dissertation, I aim to demonstrate that the debate between legal positivism and natural law theory cannot be settled through moral argumentation. To demonstrate this point, I lay out three criteria that must be fulfilled if a moral argument for a given theory is to succeed. I then examine arguments that have been put forth in the past in reference to the behaviour of citizens as well as judges. By showing the difficulty these arguments have in satisfying the three criteria, I simultaneously cast doubt on the possibility that future arguments of this kind will be successful. My aim is to put an end to a current trend in jurisprudence--choosing a conceptual theory of law on moral grounds. By doing so, I hope to refocus the debate on descriptive jurisprudence. / Thesis / Master of Arts (MA)