 The “Four-Seven” debate (which was clearly deeply related to Principle and material force) originated from a series of correspondences between T’oegye and Kobong, penname of Ki Taesŭng (1527–1572), and later it was continued on between Yulgok and Ugye, penname of Sŏng Hon (1536–1598). T’oegye originally suggested that the four beginnings and seven feelings had different origins, and this instigated the original debate with Kobong, who did not agree with T’oegye’s dualistic approach: that Principle (i) was the source of the four beginnings, while the material force was the source of the seven feelings. Kobong was more interested in ki’s moral and activating function, and considered i and ki as inseparable, especially when it came to “their presence in actual things” (Kalton 1994: 6). The issue at hand was how could the morally good Principle, manifested to its highest form in (wo)mankind, be corrupt, or led astray, in the sense that people clearly do not always conduct themselves in a kind-hearted manner towards others. Though T’oegye revised his view, he still gave primacy to Principle and maintained that it always initially preceded ki when we act morally, or rather that Principle guided ki, like a rider guiding a horse. Hence, T’oegye upheld the moralistic perfection and integrity of Principle by suggesting that things could be less than perfect, and human behaviour sometimes not good, as a result of the interaction with the material force, which could be affected/corrupted depending on the concrete circumstances of its actualisation in concrete form/action.