 In his books on “reduction of physical theories,” Scheibe (1997, 1999) developed his own concept of theory, which to some extent can be considered an intermediate position between those of Ludwig and Sneed. For example, he conveniently combines the model-theoretical and syntactical styles of Sneed and Ludwig, respectively. Since his main concern is reduction, he does not need to cover all the aspects of physical theories that are treated in the other approaches. As already mentioned, he proposes a more flexible concept of reduction that is open to extensions arising from new case studies.