Since 'positivists', 'hermeneuticists', and 'dialecticians' have all focused upon psychoanalysis as a paradigm in their scientific-theoretic debates, psychoanalysts too have taken note of these controversies. Mentzos presents a series of criteria by which sciences may be divided into categories. While he accords these criteria a certain significance in making differentiations, he does not regard them as exclusive. According to Mentzos, the analysis of symbol systems requires scientifically controlled procedures. So far, none have been devised that are adequate for the evaluation of the peculiar personal-formative processes which are remobilized in therapy.