Psychotherapy and "scientific" research - Some problems of the relationship between psychotherapy and scientific research are examined. The following aspects are discussed: the theory of demarcation between science and non-science, the problem of replicability, "hard" and "soft" sciences, complexity and chaos theory, the levels of probability and indeterminacy, the inductive-deductive circle, abduction, etc. Clinical material is presented in order to exemplify the issues under discussion. Some of the problems met by empirical research in psychotherapy (for example the manualization of psychotherapy techniques) are described, and the phases of the history of psychotherapy research movement are summarized. (This intervention is a discussion of the paper by the physicist Ferdinando Bersani "Replicability in science: Myth or reality?". Psicoterapia e Scienze Umane, 2009, XLIII, 1: 59-76). [KEY WORDS: science, psychotherapy research, epistemology, replicability, psychoanalytic research]