Knowledge-based systems - Utopia and Reality. The following article is a response to K. Mainzer's 'Knowledge-Based Systems; Remarks on the Philosophy of Technology and Artificial Intelligence'. We show, that Mainzer does not reach any of his aims - to analyse the possibilities and limits of AI-technology, - to reduce anxiousness and hostility against AI, which is motivated by phantastic speculations, - to evaluate the factual impact of AI on our lives and on society. His article contributes on the contrary to (...) phantastic speculations, which are not technologically justified in any way. There are two main reasons for his misleading view: (a) the state of the art of knowledge-based systems is incorrectly described; (b) the roots, paradigms and alternatives to AI are not in the least sufficiently analysed. We examine issues (a) and (b) in Chapter 1 and Chapter 2. In Chapter 3 we discuss, how the conclusions, which Mainzer draws, have to be modified. In analysing the lines of argumentation of Mainzer we try to clarify the methodological errors and the philosophical attitude of Mainzer, which is in many respects not adequate to the subject of the article. (shrink)