Most scholars dealing with neo-Kantianism emphasize the existence of an explicit origin that characterizes neo-Kantianism as a clearly defined ‘movement’ with certain objects. In spite of the fact that differences between various neo-Kantian authors are mentioned in the current discourse (e. g. ‘Südwestdeutsche’ and ‘Marburger Schule’) scholars claim a singular unity of all neo-Kantian debates represented in the problem of ‘Geltung’. This is used to construct a certain relevance of neo-Kantianism in today’s philosophy. My contribution will pursue a historical approach (...) following Klaus Christian Köhnke’s and Ulrich Sieg’s demands. Instead of sketching systematic topics I pay further attention to the context in which an essence of neo-Kantianism was claimed or rejected. In doing so I will examine the discussions on the doctrine of postulates in Kant’s philosophy mainly led by Hans Vaihinger’s ‘Philosophy of As If’ and the impact of Eduard von Hartmann on the genesis of neo-Kantianism. I conclude that the definition of a consistent neo-Kantian ‘movement’ was an effect of rejecting spiritualist interpretations of the doctrine of postulates and in the following a rejection of the whole doctrine as ‘mysticism’ in canonical Kant interpretations. (shrink)