Each word points to a familiar object, like a dictionary or even a picture book. In a real language, however, words take on meaning only from other words. Batty philosophers are not exactly catty because of a difference in sounds, and semantics works much the same way. Those clowns are not exactly insane or comical either, because shades of meaning emerge by contrast. One has a system, a structure, without a base.
Language is like a computer network without a central computer.
Picking up on Freud's idea of free associations, Lacan tried Structuralism on the mind. The reward for him was in that mysteriously productive deferral. He marveled at a word's absence of fixed reference taken alone, apart from a context in language. Lacan had brought together Freud's technique, of word association, with his subject matter, desire. In this way he found new relevance in Freud's whole vocabulary of unconscious urges.