The purpose of this paper is to investigate Lacan's concept of act. Therefore, firstly, under the guiding-thread of Lacan's seminary The Psychoanalytical Act (1967-68), the concept of act in five main theses is analyzed. Next, a connection is made on the concept of psychoanalytical act with that of passage to the act on the basis of the hypothesis of a constitutive failure of the act. Lastly, the notion of a "failed passage to the act" as that failure which reveals the truth of object a is interpreted.
Act; psychoanalytical act; passage to the act; object a