Some of the epistemological consequences of adopting the narrative point of view in psychotherapy are explored. Attempts to apply principles and norms from the philosophy of science to psychotherapy are criticized, since psychotherapy is not a science, but a technique. In addition that knowledge could increase by apposition without transforming the subject who is knowing are discussed. Natural science and hermeneutic metaphors are not suitable for understanding the practice of psychotherapy. Traditionally, the interpretation of symptoms or problems to solve has been the main instrument in therapy. In other words, the therapist tries to look for the truth hidden under the symptom, which then becomes a sign. Our proposition is to substitute these metaphors for the paradigm of text commentary. Text commentary, instead of providing a unique truth, provides a set of meanings suggested by a commentary. Characteristics that allow one to distinguish a good and a bad commentary, and implications of the paradigm described for the training of psychotherapists, are discussed.