  The idea of a Pure Theory of Law was propounded by the formidable Austrian jurist and philosopher Hans Kelsen (1881–1973) (see the bibliographical note). Kelsen began his long career as a legal theorist at the beginning of the 20th century. The traditional legal philosophies at the time, were, Kelsen claimed, hopelessly contaminated with political ideology and moralizing on the one hand, or with attempts to reduce the law to natural or social sciences, on the other hand. He found both of these reductionist endeavors seriously flawed.  Instead, Kelsen suggested a ‘pure’ theory of law which would avoid reductionism of any kind. The jurisprudence Kelsen propounded “characterizes itself as a ‘pure’ theory of law because it aims at cognition focused on the law alone” and this purity serves as its “basic methodological principle” (PT1, 7).