Lacan, as we have seen in our discussion of Freud,....

“ Lacan, as we have seen in our discussion of Freud, regards the unconscious as structured like a language. This is not only because it works by metaphor and metonymy: it is also because, like language itself for the post-structuralists, it is composed less of signs — stable meanings — than of signifiers. If you dream of a horse, it is not immediately obvious what this signifies: it may have many contradictory meanings, may be just one of a whole chain of signifiers with equally multiple meanings. The image of the horse, that is to say, is not a sign in Saussure’s sense - it does not have one determined signified tied neatly to its tail - but is a signifier which may be attached to many different signifieds, and which may itself bear the traces of the other signifiers which surround it. (I was not aware, when I wrote the above sentence, of the word-play involved in ‘horse’ and ‘tail’: one signifier interacted with another against my conscious intention.) The unconscious is just a continual movement and activity of signifiers, whose signifieds are often inaccessible to us because they are repressed. This is why Lacan speaks of the unconscious as a ‘sliding of the signified beneath the signifier’, as a constant fading and evaporation of meaning, a bizarre ‘modernist’ text which is almost unreadable and which will certainly never yield up its final secrets to interpretation. ”

Terry Eagleton

From : Literary Theory: An Introduction