Description: In order to evaluate the scientific quality of proposals, the following information must be provided Herbart's realism and Dewey's pragmatism contain the systematic main concept "interaction". But German realism as in the Herbart-School and American pragmatism from Peirce to Dewey are unknown as interrelating traditions in the history of ideas. These unknown relations form the topic of this paper, which represents aspects from a postdoctoral qualification project. Herbart's definition of education means empirical teaching as well as moral education: he calls it constituting circles of thoughts ("Bildung von Gedankenkreisen") in a pupil's soul. But constituting circles of thoughts is something quite different from teaching ("Unterricht") and education ("Erziehung"): teaching is based on Herbart's realism in metaphysical psychology, but education is founded in Herbart's idealism in ethics.The formation of thoughts through instruction as realistic knowledge results from the interaction of experience and mind, grounding on the realism of the self as an interaction between soul and body in Herbart's metaphysical psychology. But the moral formation of thoughts in education follows the a priori ideas which Herbart founded in his idealistic ethics. He emphasizes the idea's contrariety to empirical reality of society. It is not possible to ground ethics on metaphysical or psychological realism. Idealist moral education potentially destroys realistic social education, which means teaching pupils to develop a variety of interest. What can a pupil do if his realistic knowledge of history and society contradicts Herbart's moral ideas as categorical maxims of behaviour? Herbart's pedagogy fundamentally contains a contradiction between realistic teaching as the interaction of experience and mind, and idealistic education that submits realistic thinking and action to a priori ideas. The difference between realism and idealism marks the development of Herbartianism in psychology, education and ethics in philosophy after Herbart. From 1861 to 1896 the German magazine "Zeitschrift für exacte Philosophie im Sinne des neuern philosophischen Realismus" was published, thus providing a journal for the Herbart-School. The articles deal with all aspects of Herbart's philosophy, which are of special interest for the topic of the present paper, a critique of German idealism and a continuation of Herbart's interaction as a main aspect of realism in metaphysics and psychology. But most important for the influence of Herbart's interaction in realism on Dewey's conception of realist interaction ("Wechselwirkung") were the developments of psychology by Müller, Fechner, Lotze, Helmholtz and others dealing with Wundt's physiological psychology after Herbart.Wundt used the conception of interaction as a basic idea in psychology, folk-psychology (or social psychology) and ethics. Interaction here means the mutual causality of psychic experience and physical experience, soul and body, man and environment as culture and nature, science and philosophy, knowledge and thinking. Wundt's ethics basically contains the interaction of scientific knowledge and speculative thinking. Ethical thinking transforms scientific knowledge to ideas, and ethical ideas define practical habits of individuals and culture in an empirical society in a hypothetical manner. Wundt formulates the "principle of heteronomy of purposes", equal to the pragmatic maxim by Peirce, James, and Dewey in logic, ethics and education. Dewey's achievement is to interpret the physiological psychology, especially Wundt's. Dewey made psychology his philosophical method. Physiological psychology is the foundation of Dewey's ethical, educational, and democratic ideas. Herbart's metaphysical, psychological and educational realism of interaction between inner experience and outer experience fundamentally influenced the development of psychology as a science in the 19th century. Physiological psychology as a science and the conception of interaction grounded Dewey's philosophy in his early writings and mark the main idea of Dewey's theoretical, ethical, educational, and democratic pragmatism in his early, middle, and later works. Based on the history of ideas Herbart's interaction of soul and body influenced Dewey's theory of interaction, which defines his philosophy of education as the interaction of knowledge and thinking in "Democracy and Education". Dewey's ethical and educational conception of interaction goes back historically to interaction in Herbart's realism. Methodology: The contents of the paper are based on research on and interpretations of the original writings by members of the Herbart-School and of American pragmatism. Furthermore, publications dealing with historical relations between German realism and American pragmatism were used - publications which were published since the end of the 19th century but are actually "unknown and forgotten". Conclusions: The paper presents in short the main aspects of a postdoctoral research project. Its conclusions are aimed to show that:- interaction marks the principal item of German realism from Herbart to Wundt and of American pragmatism from Peirce to Dewey- German realism and American pragmatism are related through the conception of interaction in the history of ideas in education, psychology, ethics, logic and metaphysics- the pedagogical term "educational interaction" (in German "pädagogische Interaktion") historically and essentially goes back to pragmatism and realism, which were especially established in scientific psychology and ethics following the history of ideas from Herbart to Dewey- Dewey believes it is possible to outgrow dualism in the philosophy of education, dualism of soul and body, mind and matter, and thus the contradiction of individual and community in democracy and education through the concept of interaction based on scientific or physiological psychology, which goes back to German realism and its founder Herbart