 Nevertheless, the various explanations all give us some hints into the complexity of Bohr’s thinking concerning the description of physical experiments. At different times, he seems to put emphasis on one aspect rather than another, depending on the specific context of discussion. Sometimes he was occupied with the interpretation of experiments, sometimes with the relationship between actual experiments and the formulation of quantum mechanics. In emphasizing the necessity of classical concepts for the description of quantum phenomena, Bohr might have been influenced by Kantian-like ideas or neo-Kantianism (Hooker, 1994). But if so, he was a naturalized or a pragmatized Kantian. The classical concepts are merely explications of common-sense concepts that are already a result of our perceptual adaptation to the world. These concepts and the conditions of their application determine the conditions for objective knowledge. The discovery of the quantization of action has revealed to us, however, that we cannot apply these concepts to quantum objects as we did in classical physics. The use of classical concepts in the domain of quantum mechanics has to be restricted with respect to their use in classical mechanics. Now kinematic and dynamic properties (represented by conjugate variables) can be meaningfully ascribed to the object only in relation to some actual experimental results, whereas classical physics attributes such properties to the object regardless of whether we actually observe them or not. In other words, Bohr denied that classical concepts could be used to attribute properties to a physical world in-itself behind the perceptual phenomena, i.e. properties different from those being observed. In contrast, classical physics rests on an idealization, he said, in the sense that it assumes that the physical world has these properties in-itself, i.e. as inherent properties, independent of their actual observation.