On the concept of systematization in the Kemeny-Oppenheim approach to intertheoretical reduction

In 1956, John G. Kemeny and Paul Oppenheim proposed an approach to intertheoretical reduction as an alternative to that of Ernest Nagel. However, they neglected to provide a clear definition of its basic concept of systematization. After decades of languishing in the shadows, new interest in the KO approach is emerging. Nevertheless, there are still misunderstandings regarding this basic concept. The present paper elucidates this concept by returning to Oppenheim's hitherto little-noticed publications from the 1920s and 1930s, which Kemeny and Oppenheim obviously used as guidance in 1956. Reappraising Oppenheim's early writings delivers two significant payoffs: new clarity in understanding the concept of systematization as well as a more solid grasp of the structure of this approach as a distinctive combination of explanation and systematization.