This quantitative methodology would become known as Humboldtian science. Another way of classifying algorithms is by their design methodology or paradigm. It combines elements of philosophy, methodology, and theory. Those advocating the re-establishment of a Caliphate differed in their methodology and approach. This view has been challenged as inaccurate and based on flawed research methodology. The principles of his cultural psychological methodology were only worked out later. Other researchers questioned aspects of the methodology. He also contributes to the extreme programming software development methodology. Subsequent estimates have followed the same basic methodology. Greek historians greatly contributed to the development of historical methodology. They use different definitions, methodology, and sources. Pairwise comparisons form the basis of the Elo rating methodology. Popper always made a clear distinction between the "logic" of science and its applied "methodology". Many disciplines are typically involved in the "8Ds" methodology. It is less extractive when utilized in a standard tincture methodology.