In this paper, the author seeks to analyse the nature and function of metapsychological theory in Freudian psychoanalysis. He shows that Freudian psychoanalytic theory is composed of an empirical part—the psychology of clinical facts—and a speculative part—metapsychology. Freud considers this latter part as being a speculative superstructure of value that is only heuristic, capable of being supplanted by other superstructures of the same type. The author sustains the idea that this metapsychology is the fruit of speculative method, whose foundations were elaborated by philosophers and epistemologists before Freud, including Immanuel Kant and Ernst Mach. He concludes with considerations regarding the future of metapsychological theorisation, presenting criticisms of Freudian metapsychology offered by both philosophers and psychoanalysts, and pointing to the perspective opened by Donald W. Winnicott of a psychoanalysis without metapsychology.