One of the most dramatic changes in the history of modern China is its acceptance of modern science. For centuries the Chinese literati had been exploiting the power of the ideas of Qi, yin-yang, and the five phases (wu xing) for describing their cosmology, which did not distinguish the natural and human worlds. That set of knowledge was seriously challenged in the second half of the nineteenth century when Western powers brought not only guns and steam warships but also a much more complex system of understanding the material world. China had to accept the new knowledge because it was deeply intertwined with how guns and warships were built, and hence the survival of the empire was at stake. This study explores how the epistemological obstacles of the Qi theory could be broken down and new knowledge reconstructed with newly invented terms through translations, focusing on the understanding of matter. By doing so it examines the question of what constitute knowledge in Chinese culture and its changes in the late nineteenth century.