pp. 42-43

隐喻和转喻；凝缩和移置；无意识如语言那样结构：
Jakobson pointed out that metaphor is an act of substitution of one term for another and thus corresponded to the paradigmatic axis, or the axis of selection. Metonymy is a relation of contiguity, in that one term refers to another because it is associated or adjacent to it, and therefore it corresponds to the syntagmatic axis, or the axis of combination. 
Lacan saw in Jakobson’s structural model of metaphor and metonymy a direct correspondence with Freud’s processes of dream work: condensation and displacement. 
Condensation designates the process whereby two or more signs or images in a dream are combined to form a composite image that is then invested with the meaning of both its constitutive elements. In persecutory dreams, for example, the dreamer may dream that they are being punished by an unknown authority figure and try to identify that figure with someone in their life. This figure may well in fact not be a single person, however, but a composite, or condensation, of a number of different persons – parental figures, employer or partner. All of the ambivalent feelings that the dreamer has around these figures combine into a single persecutor in the dream. 
Displacement describes the process through which meaning is transferred from one sign to another. Let us take the example of anxiety dreams. In anxiety dreams the dreamer may become anxious about some very minor incident in their lives, but this functions as simply a way of avoiding, or displacing, a much more serious problem that they are facing. These two processes are what Freud called primary processes in contrast to the secondary processes of conscious thought. 
By mapping Jakobson’s distinction between metaphor and metonymy on to Freud’s primary processes Lacan was finally able to demonstrate how the unconscious was structured like a language. The unconscious, he argued, operates according to the rules of metaphor and metonymy.