To the question, "why is topology necessary to psychoanalysis?", one can answer that it is necessitated by the extension of psychoanalytical theory, as an answer to the problems both Freud and Lacan handed down. Fundamentally, one has to grasp that topology in psychoanalysis is not a mathematical application, but the invention of a method. Indeed, said method enables the construction of structural analogies, in other words structural similarities allowing us to think the causality of subjective events as modification of locations and places constituting the structure. This is what I call subjective topology.