Book excerpt: If we consider how theoretical operations belonging to the methodological inventory of linguistics are carried out (i. e. the way linguistic theories are set up), three main criteria suggest themselves for classifying them: (1) Both, nature and type of the aims of the scientific knowledge applied which allow to specify the epistemological interests as well as the theoretical impact constituting the purpose of linguistic operations; (2) the nature of the intellectual procedures in connection with which a set of intersubjectively acceptable operations should guarantee that current postulates of the theory of science be maintained; (3) the set of data serving as an empirical basis for the theories to be estab lished on the one hand and as a correlate for the further development, the testing and the evaluation of theories on the other hand. It is to be considered a basic concept (as well as a motive) of current text linguistic research that due to the linguistic analysis of discourses a further development of linguistics has set in or is still to be achieved as regards the three criteria mentioned above. Therefore, if we want to estimate text-linguistic approaches (or concepts), works (methods), or knowledge (results) we should take the view allowing for the general valuation of the linguistic discipline or one of its sub-disciplines. This should be done with respect to the contributions gathered in this volume as well.