The possibilities of applying empirical research methods to the psychoanalytical treatment situation are discussed. Until now, the application of such methods has been too closely bound to the fixing of aims in standard quantitative scientific terms. Frequently "reasons" in psychological areas have been compared to "causes" in scientific terms. As a result, a displacement has occured in the understanding of the reciprocality and circular nature of communication processes. In order to achieve a differentiation between scientific approaches it has proved useful to contrast concepts of linear-causal determination with those of interaction. The consequences of placing varying emphasis on such concepts within the therapeutic situation are described. The important differentiation between a level of working alliance and one of transference and countertransference processes in psychoanalytical treatment technique may perhaps be pursued according to basic logical concepts. On the level of the working alliance, the therapeutic relationship is understood to be mainly linear-causal: working alliance does, of course, mean working together, however, the analyst is seen to evoke a specific effect in the patient, a specific way in which attitudes and fantasies are questioned. When processes of transference and countertransference have reached a specific intensity, the constellations of the relationship can be more precisely comprehended in terms of parameters based on interactional concepts: specific unconscious processes in a given therapeutic situation can most be easily be discerned in the reciprocality of feelings, associations and reactions, and not in terms of a theory which persits in conceptions of linear-causal determination. Hitherto, it has hardly been possible to comprehend those processes where interactional determination predominates, in quantative terms.