Abstract

This study analyzes the concepts of the threefold heavens, threefold spiritual natures, and three minds in Son Byeong-hui’s thought and examines their interrelations. Son classified the inner Heaven of human beings into Formless Heaven (無形天), Sentient Heaven (有情天), and Habitual Heaven (習慣天), and correspondingly identified threefold spiritual capacities: Wongakseong (圓覺性), Bigakseong (比覺性), and Hyeolgakseong (血覺性). This structure shows that the spirituality of Heaven may manifest transparently in accordance with its essence or appear in a distorted form. Drawing on Neo-Confucian notions of seongni 性 理 and simgi 心氣 and the Buddhist idea of tranquil state of emptiness, freedom, and equality. Son systematized the process by which spirituality becomes actualized through the workings of the mind. He also clarified the distinction between seongni and simgi through the dictum “cultivating both nature and mind” (性心雙修) and presented the transformation of the body (以身換性) as the path to a sanctified personality grounded in desirelessness and the principle of non-action. This article argues that such spiritual-philosophical dimensions of Son’s thought reveal the modern significance of Donghak, contributing to a reinterpretation of the intersection between religion and philosophy in modern Korean intellectual history.