Jacques Lacan (1901–1981) was a psychoanalyst who was barred from the International Psychoanalytic Association for his ideas, which nonetheless were very influential. His main works are Ecrits (Writings; 1966), The Language of the Self (1978), and his published seminars.

Lacan applied a Saussurian notion of the linguistic order to Freudian psychology. He thought that metaphor and metonymy (substitution of an attribute of a thing for a thing itself) were the main unconscious mechanisms and that psychotherapy literally works as a form of speech that corrects speech by reinserting into discourse what has been obscured from it by neurosis. Lacan is famous for his claim that the ego consists merely of identifications made imaginatively. He meant that human beings imagine themselves as having certain characteristics at an early age and that is how the self develops. Speech creates social connection, but language is a formal system in which words derive meanings from other words only.