Mou Zong-san interprets Taoism as the ”Metaphysics in the line of vision” based on his understanding of Laozi. What he mainly concerns is not whether Tao is subjective or objective, but how to interpret the ”unspeakable” Tao. Tao is nothing and empty, so it's difficult to interpret it as any objective reality. Mou Zong-san finds a new way to interpret Tao, which is to disclose the content of Tao from the function of the subjective state of mind. He strongly queried the traditional interpretation which considered Tao as Substance, entity or Idea. His understanding is convincing on the basis of Laozi and his insights into Zhuagnzi and Wang Bi's commentaries of Laozi, but sometimes he had to misinterpret the text in order to make his interpretation consistent, which reveals the limitation of his interpretation. Mou Zong-san absorbs Heidegger's non-objectified way of thinking which could have made up for the limitation, but he did not realize it for he could not fully understand the phenomenological approach of Heidegger.