Beyond the discussion of empirical and hermeneutical methodology the comparison of constitutional law can be understood from a knowledge-based approach. Based on legal knowledge of a particular legal system constitutional comparison creates an inter-legal knowledge, which is per se not part of legal order, but determines a specific interrelation between different legal systems. This comparative constitutional knowledge is the result of abstraction and interrelation. It does not create legal knowledge itself, but can be used for different purposes (like theoretical conclusions or practical legal argumentation). In a pluralistic understanding comparative constitutional knowledge transforms the knowledge of different legal orders, while using a plurality of comparative methods. The latter are determined by the purpose of the comparison itself, which shall be made transparent in the overall comparison of constitutional law.