拉岡曾說：「無意識像語言一般被結構。」但究竟無意識如何能夠透過語言的機制被了解？又或者，拉岡所謂的語言是如何被結構以至於可以解釋無意識？本文從拉岡文章中和語言最有直接關係的《第三講》第十七章〈隱喻及轉喻之一〉中的一個註腳出發，循溯拉岡文中的隱喻及輕喻與語言學家羅曼。雅可布森的失語症的關聯，並企圖釐清雅可布森如何以結構取向的相似性及連結性觀點挪用及改寫傳統上對隱喻及轉喻的定義作爲其失語症分類的基礎：而拉岡又如何承繼及再度改寫雅可布森的隱喻及轉喻來闡釋精神分析應該以隱喻及轉喻這兩種邏輯公式所昭示的意符系統「之中」的結構關係作爲了解無意識的途徑，而非這個已經存在的關係「之外」的意符與意旨的關係而構成的象徵理論。

Jacques Lacan said, ”The unconscious is structured like a language.” Then, how can the unconscious be understood in terms of the mechanism of language? And indeed, how is language structured so as to be able to explain the unconscious? This paper is inspired with footnote no. 7 from one of Lacan's writings which can be concerned most relevant to the discussion of language, i.e., Chapter 17, ”Metaphor and Metonymy: Ⅰ” of his Seminar Ⅲ. In it, Lacan pinpoints the relation between his metaphor and metonymy and those of Roman Jakobson's. This paper intends to carry this note on to trace the affiliation of these two thinkers' approaches to appropriating and rewriting metaphor and metonymy. aiming to show first, in which perspective Lacan borrows and rewrites Jacobson's concepts of combination and congruity to fit his own explanation of metaphor and metonymy and second, in which way Lacan depicts metaphor and metonyrny as two topographies of the unconscious so as to declare that it is the relation inside the signifying system that is worthy of the attention in the field of psychoanalysis rather than symbolization, a technique having been falsely adapted by the analysts since Freud to unveil the patient's unconscious by throwing upon it an erroneous meaning from the outside of the signifying system.