Abstract：The identity of self as a cognizing subject is a very import an t issue in the realm of philosophy. This issue, however, has been regarded unass ailabl e by ontology before Cartesianism so as to be parenthesized. Epistemology has al ready questioned the nature of cognizing subject, nevertheless, it still attribu tes identity, oneness, and self-sufficiency to self. The revolution of cognitio n induced by philology makes people think it for the first time, and subverts dr astically the identity, oneness, and self-sufficiency of self. However, this su b version does not come from metaphysics but from Lacanian psychoanalysis. Owing t o the discovery of Lacan, we have finally understand that the identity, oneness, and self-sufficiency of self are only a kind of illusion, for self is essent ially another. Self ends up recognizing that his being has never been anythin g more than his own construction in the imaginary and that this construction und ercuts all certainty in him. For in the work he does to reconstruct it for anoth er, he encounters anew the fundamental alienation that made him construct it lik e another, and that has always destined it to be taken away from him by another.
