If modernity is manifested as essentialism, postmodernity is manifested as anti-essentialism. Modernity is, in essence, human beings' discovery of their own power, and is based on rational knowledge that has grasped the essence of things. In fact, in the discourse system of modernity, the various concepts of "essence" connote nothing but people's imaginative constructions and rational conjectures about objects. In the past, our order, be it internal or external, was in essence guaranteed by God. Afterwards, all "essences", as essences, must rationally prove the reason for their existence. In the postmodern context and discourse system, God, and also the "human being" who has created essence, has "died". We should not simply resume the belief in traditional essence, but should reconstruct, on the basis of a full understanding of the intellectual meaning of postmodernity's challenges, some historicity, practicality, and the concept of essence that accords with the historical as well as communicative rationality. We must realize that the essence of things is the essence of particular things in a particular stage of development, internally containing infinite differences and variety. Only things with postmodern traits contain modernity, and only the concept of essence that conceives difference accords with time.