this area of specialization. Second, it was a measure of relative centralization or decentralization. Third, a fully centralized system of law would also correspond to a unique Grundnorm or Basic norm which would not be inferior to any other norm in the hierarchy due to its placement at the utmost foundation of the hierarchy (see Grundnorm section below). The de-ideologicalization of positive law Kelsen, during the time period of his education and legal training in fin-de-siecle Europe, had inherited a highly ambiguous definition of natural law which could be presented as having metaphysical, theological, philosophical, political, religious, or ideological components depending on any one of numerous sources who might desire to utilize the term. For Kelsen, this ambiguity in the definition of natural made it unusable in any practical sense for a modern approach to understanding the science of law. Kelsen explicitly defined positive law to deal with the many ambiguities he associated with the use of natural law in his time, along with the negative influence which it had upon the reception of what was meant even by positive law in contexts apparently removed from the domain of influence normally associated with natural law. Science of law The redefinition of the science of law and legal science to meet the requirements of modern law in the twentieth century was of significant concern to Kelsen. Kelsen wrote book-length studies detailing the many distinctions to be made between the natural sciences and their associated methodology of causal reasoning in contrast to methodology of normative reasoning which he saw as more directly suited to the legal sciences. The science of law and legal science were key methodological distinctions which were of high importance to Kelsen in the development of the pure theory of law and the general project of removing ambiguous ideological elements from having undue influence on the development of modern twentieth century law. In his last years, Kelsen turned to a comprehensive presentation of his ideas on norms. The unfinished manuscript was published posthumously as Allgemeine Theorie der Normen (General Theory of Norms). Political philosophy Kelsen's very first book (see Section above) was written about the political philosophy of Dante Alighieri and it was only with his second book that Kelsen started to write book length studies about the philosophy of law and its practical applications. Baume speaks of Kelsen's political philosophy concerning judicial review as coming closest to Ronald