How learning relates to development in children of school age is the most central and fundamental question. Without an answer to this, problems of pedagogical psychology and analysis of the pedagogical process can neither be properly resolved nor even stated. Nevertheless, this question remains the most obscure and unexplained of all the basic concepts on which the science of child development depends for its clarification of the processes involved in children's education. However, this theoretical confusion in no way subtracts the question from all the contemporary research relating to it. Not a single concrete piece of research has been able to avoid it. If the question remains methodologically unclarified, what this means is that the concrete investigations are based on theoretically vague, critically unbalanced, sometimes inwardly contradictory and unthought-out postulates and premises, irrelevant answers which are the source of a whole range of mistakes. If one tries to find a single root cause for all the very profound mistakes and confusions that are found in this sphere, it would be no exaggeration to say that the main one is precisely this question. The task at hand is to bring to the surface those unconscious and vague theoretical solutions to the question that lie at the heart of most of the research, to examine them critically, starting from experimental givens and theoretical considerations and to suggest, if only in the most general and condensed form, how the problem might be solved. (This article was translated by Stanley Mitchell.)