Abstract
Seitaro Tsuboi, a professor of petrology at the Imperial University of Tokyo, played the central role in introducing Bowen's theory to the petrological community in Japan before World War II. Influenced by his predecessors, Tsuboi became interested in so called "new petrology " employing physicochemical methods. To Tsuboi, Bowen's theory was the most important amoung them. Based on both his uniquely developed optical method to examine minerals and his own research philosophy, he could add more details to Bowen's theory. Facts suggest that Tsuboi's study was received certain recognition in his days. However, it does not mean that Bowen's theory was either well accepted or deeply understood since such a "new petrology " was not necessary for the majority of researchers who employed traditional descriptive methods. Although no strong dislike to Bowen's theory came up, some petrologists felt somewhat uneasy about the research methods. Nevertheless, there were not serious controversies between Tsuboi and those scholars partly because their understanding the theory and physicochemical methods was not deep enough to develop effective criticisms and partly because the theory and Tsuboi's methods were not widely penetrated into the community. However, after World War II, serious controversies around the theory came up where Tsuboi was criticized as a man of formalism who neglected the observed facts. The fact was that Tsuboi actually always kept it in his mind that Bowen's theory was neither perfect nor absolutely true; therefore, he pursued the logical clarity between theoretically induced ideas and observed facts. These will be discussed in later papers.
