This work attempts to trace the route in which Yangming Philosophy was spread to Joseon, by exploring how both the theory of principle regulating normal and specific situations (經權論) and the theory of realistic pragmatism(事勢論) were adopted by Myung-kil Choi (崔鳴吉), Ik Cho (趙翼), Yu Chang (張維), and others who actively responded to the contemporary problems and crises of the 17th-Century Joseon. It was urgently needed for these figures to reconstruct and reform the country, particularly state system and institutions, badly damaged by the Japanese Invasion of Korea in 1592 (壬辰倭亂) and the Ching Dynasty’s Invasion of Korea in 1636 (丙子胡亂). In particular, as a result of the latter of the two wars, the doctrines of Chu-Hsi(朱熹) such as the Identity Sense theory (名分論), the Moral Sense theory (義理論), and the theory of China and Barbarian (華夷論) no longer corresponded to realities of Joseon. This phenomenon brought about a severe panic among the contemporary ruling classes.
Myung-kil Choi, Ik Cho, Yu Chang, and other scholars and officials of Seo-in tried hard to probe into theories and ways to overcome such crises. For example, Myung-kil Choi, by arguing for making peace of Qing which he based on the theory of realistic pragmatism, attempted to tune the postwar relationship between the Joseon Dynasty and the Ching Dynasty. Both Ik Cho and Yu Chang, drawing on a realistic sense of actual benefit not fettered by cause, presented the theory of Adaptability (變通論). Their various suggestions had a distinctive feature which, by limiting the existing vested rights, tried to correct the problems of the Yang-ban system and the landlord system. Their views were much different from those who held on to the Identity and Moral Sense theory (義理名分論) of the doctrines of Neo-confucianism. The base of the difference, while it could be found in the theoty of Adaptability of Seo-in which originated from the theory of reformation of Yi Yi(李珥), had also much to do with the tradition of Yangming philosophy which had been kept up thorough scholastic mantles, marriage neeworks, and academic exchanges. The scholars and officials, by either accepting or understanding Yangming philosophy, went beyond the limit set by the Identity and Moral Sense theory and, thereby, were able to suggest realistic ways to deal with the contemporary problems and crises.