Welcome to the opening of our journey into East Asian philosophy. This module introduces the two towering figures who defined the intellectual landscape of their respective eras: Zhu Xi, the great synthesizer of Neo-Confucianism in 12th-century China, and Jeong Yak-yong (Dasan), the representative realist scholar of 18th-century Korea. We delve into the core philosophical debate that shaped East Asian thought for centuries. We begin by exploring Zhu Xi’s Li-Qi Theory, a grand metaphysical framework that views human nature as an extension of cosmic principles. You will learn how Zhu Xi established a rigorous system where moral cultivation starts with understanding the Principle (Li) inherent in all things. Then, we transition to Jeong Yak-yong’s critical response. Breaking away from abstract metaphysics, Jeong Yak-yong shifted the focus from "What we are" to "What we do." We will examine his "Theory of Inclination" and his insistence that virtue is not a pre-installed essence but a result of active, concrete practice.

In this lecture, Prof. Soyoung You will help you understand Dasan’s redefinition of Confucian learning. Situating Dasan within the dynamic intellectual environment shaped by Evidential Learning and Western Learning, she explains how Dasan challenged Zhu Xi’s interpretation of The Great Learning and instead positioned The Doctrine of the Mean as the foundation of Confucian learning. Centering on sincerity (seong), self-examination (sindok), and reverent moral vigilance (gyesin gonggu) under Sangje, Dasan redefined learning as the cultivation of the sindok gunja, emphasizing continuous moral vigilance.

In this week, Prof. Dobin Choi explains the theme of “human nature” in later Confucianism through a comparative study of Zhu Xi and Dasan Jeong Yak-yong. Revisiting the long-standing Confucian concern with human nature (xing, 性), he contrasts Zhu Xi’s metaphysical account grounded in Principle (Li, 理) with Dasan’s more empirical interpretation centered on taste (Giho, 嗜好). Engaging especially with Mengzi’s claim that human nature is inherently good, the lecture highlights how each thinker reinterprets the classical tradition in a distinctive way. Their contrasting views of human nature ultimately lead to different visions of moral cultivation and the path toward ethical self-formation.

In this lecture, Prof. Dobin Choi compares Zhu Xi and Dasan Jeong Yak-yong on the Confucian ideal of moral self-cultivation through the concept of Shu (sympathetic concern). Drawing on passages from the Analects and Mengzi, he explains how Zhu Xi interprets “all things are within me” through the metaphysical theory of Li Principle, emphasizing inward reflection and sincerity (cheng). By contrast, Dasan grounds sympathetic concern in shared human taste (giho) and everyday sentiments, highlighting interpersonal understanding and outward moral practice.

In this lecture, we explores the contrasting visions of the "good life" held by the Chinese philosopher Zhu Xi and the Korean scholar Jeong Yak-yong (Dasan). Both thinkers agree that a good life is rooted in virtue, yet they diverge significantly on the role of external circumstances and non-moral goods. In Zhu Xi's view, the tragic, short life of the virtuous Yan Yuan is as "good" as the prosperous life of Sage King Shun. In contrast, Dasan rejects this asceticism, arguing that virtues are not innate but acquired through concrete practice. Consequently, he views Shun’s flourishing life as preferable to Yan Yuan’s.

In this lecture, Prof. Youngsun Back compares Zhu Xi and Dasan Jeong Yak-yong on the question of sagehood in Confucianism. While both agree that sages and ordinary people share the same human nature, Zhu Xi explains the emergence of sages through differences in psychophysical endowments and the idea of “natural sages.” Dasan, by contrast, emphasizes human effort, arguing that all people begin with the same moral capacity and can become sages through continuous learning and self-cultivation.

After exploring the metaphysical and practical dimensions of human cultivation, we now turn our gaze toward a fascinating and often surprising topic: the moral status of non-human animals. In this session, Prof. Youngsun Back uses the animal kingdom as a mirror to reflect the core of Confucian ethics. By asking whether a tiger can be "filial" or a bee "loyal," we uncover a fundamental disagreement between our two thinkers, Zhu Xi and Jeong Yak-yong (Dasan). Through modern philosophical lenses (like Mark Rowlands’ distinction between moral subjects and moral agents) and real-life hero stories, this lecture challenges us to define what truly makes an act "moral."

This lecture by Prof. Jo Jungeun examines the music theories of Zhu Xi and Jeong Yak-yong through the Sambun sonik (三分損益) method and the formation of the twelve pitch-standards. We begin by exploring the Sambun sonik method as presented in Ancient Chinese text, the Huainanzi and the Hanshu, focusing on how the twelve pitch-standards are generated through numerical calculation. We then turn to Zhu Xi’s acceptance of this traditional framework, followed by Jeong Yak-yong’s critical response and his proposal of a new system grounded in yin–yang principles. The lecture offers a clear comparative overview of their different approaches to pitch theory.