A basic premise of humanism is the existence of a so-called stable self, which has all the beautiful qualities such as free will and independent decision. Freud's concept of unconsciousness belongs to this kind of concept, and they began to doubt and shake the humanistic fantasy about themselves. At this point, Freud is the pioneer of post-structuralism. But what Freud hoped was to bring unconscious content into consciousness, so as to eliminate depression and neurosis as much as possible-he once had a famous slogan on the relationship between unconsciousness and consciousness, that is, "I should be there wherever I am." In other words, "it" or "another self" (unconscious) will be replaced by "I" or consciousness and self-identity. Freud's aim is to strengthen the self, that is, the identity of self, ego, consciousness or reason, making it stronger than unconsciousness.

But for Lacan, this goal is impossible. The ego can't replace the unconscious, or completely expose the unconscious and control it, because for Lacan, the ego or "I" is just an illusion and a product of the unconscious itself. In Lacan's psychoanalysis, unconsciousness is the base camp of all existence. Freud devoted himself to studying how a child with all kinds of abnormal possibilities formed an unconscious and superego, and how he became a civilized, constructive (and normal heterosexual) adult. It is at this point that Lacan focuses on how children get the illusion we call "self". In his article Mirror Stage, he described this process and how children form a self-awareness about themselves, which is confirmed by the word "I".