Sources and Arrangement of the Ten Diagrams
T'oegye sees the structure of the Ten Diagrams in several ways. Basically it is split down the middle: the first five chapters present the essential framework, "based on the Tao of Heaven," as he says. They include a description of the universe (metaphysics), society (ethics), and their import for human life (learning). The remaining five chapters deal directly with self‑cultivation, the "learning of the mind‑and≠-heart." They begin with an analysis and characterization of man's inner life (psychology) and conclude with concrete practice (ascetical theory).36 Or from a slightly different perspective, the chapters on learning are the core of the whole work; the first two chapters present the great foundation which must be properly understood and the later chapters detail the fruition of learning in the actual process of self≠cultivation.37 This perspective brings out the underlying unity of the two halves of the Ten Diagrams, in which intellectual considerations and moral practice are the interdependent and dialectically related facets of the single process of self, transformation called learning. T'oegye makes a special point of this in his remarks presenting the Ten Diagrams to King Sŏnjo.
T'oegye explicitly makes mindfulness (kyŏng, ching) the central theme of the whole Ten Diagrams.38 It is absolutely fundamental for both study and practice. On the side of intellectual investigation, it stands for the mental recollection and concentration necessary for such pursuits. As for moral practice, the same mental recollection is a token of the self‑possession and reverential seriousness that are the basis of a sound and proper response to the world around us. The final two chapters are devoted entirely to the topic of mindfulness, but it is a constant subject throughout the other chapters as well.
Most of the material used for the first five chapters, those dealing with the basic framework, are so fundamental and well known as to be virtually self‑selecting. The Diagram of the Supreme Ultimate, the Western Inscription, and the Great Learning certainly are such. In Korea, as in YŁan China, the Elementary Learning was esteemed as a classic, so pairing it with the Great Learning was also a matter of course. The rules Chu Hsi wrote for his White Deer Hollow Academy were likewise well known, being inscribed on the walls of Korea's own Confucian Academy. But to extend the discussion of learning to three chapters by including them is a bit surprising. One explanation may be T'oegye's great concern with these issues, which were currently being seriously challenged in China by the Lu‑Wang school. Further motivation may have been T'oegye's concern for private academies, a Neo‑Confucian institution that with his help was just getting un≠derway in Korea.
Personal preference played a larger role in compiling the last five chapters which deal with the learning of the mind‑and‑heart. This was a fundamental aspect of the Ch'eng‑Chu school, but by nature it was more diffuse and personal and did not crystallize into universally recognized reference points such as the Diagram of the Supreme Ultimate. Chen Te‑hsiu's Classic of the Mind‑and‑Heart was, of course, a major reference point for T'oegye. It's influence is clear in the central position accorded mindfulness throughout the Ten Diagrams, and the Diagram of the Study of the Mind and Heart (chapter 8) prefaces the Classic as an expression of the essence of the work. Chu Hsi's Admonition for Mindfulness Studio (chapter 9) likewise appears in its pages. Chu Hsi's famous Treatise on Jen does not appear in the Classic itself, but it epitomizes a formulation of jen (humanity) that was prominent in the thought of Chen Te‑hsiu and occupied an important position in the Classic.
The sixth chapter, however, merits special attention. Chen's Classic avoided intellectualism, but T'oegye here reintroduces it to the learning of the mind‑and‑heart by a chapter that serves to establish a metaphysical framework for man's inner life. It is actually three diagrams, each with its own text. The first is a fairly standard pre≠sentation of basic Ch'eng‑Chu psychological theory. The second and third, however, are T'oegye's unique contribution, a summation, in effect, of his final position in the Four‑Seven Debate. In an unprec≠edented way they undertake a metaphysical analysis of the function