This paper reinvestigates Hu Shi's theory of
vernacular Chinese, setting it in the historical proceeding of modernity to
discuss the dialectical relation between the theory and the development of writings in the vernacular. In terms of synchrony and diachrony, the paper expounds how modernity functioned and its forms of expression in different periods, and analyzes the internal relevance between writings in the vernacular and modernity. This paper points out that the modern modes of thought which modern writings in the vernacular represent are the important mark of traditional China striding forward towards the modern society. During the "May 4th" Movement period when there were full of different thoughts interlocking, Hu Shi formed the theory discourse of modern literature with the theory of
vernacular Chinese that exactly accorded with requirement for
historical modernity in "May 4th" Movement times, which not only enables Chinese literature to break free of the traditional patterns to enter the modern contexts, but also to join the modernization of spiritual culture, to facilitate drawing a dividing line between modern culture formation and ancient culture formation. Thus, Hu Shi's theory of vernacular Chinese is of great value in modern transformation of Chinese culture.