Stefan Swieżawski (1907-2004) was an outstanding Polish historian of philosophy, author of, among others, Dzieje filozofii europejskiej w XV wieku (The History of European Philosophy in the Fifteenth Century) (Wydawnictwo ATK in Warsaw), the most comprehensive work in world literature devoted to the philosophy of this period. He has published 4 articles and 2 book reviews in SPCh. The aforementioned article is an excerpt from the first chapter entitled ‘Philosophical Reflection on the Perceptible World’, volume 5 of The History of European Philosophy of the Fifteenth Century, entirely devoted to the philosophy of nature, which was then (at the time of publication of the article) being prepared for printing. The article is a preview of the aforementioned volume. "The deepest drama of European philosophical thought in this period was - despite appearances to the contrary - the gradual withering away of lively and creative metaphysical reflection, especially in its deepest foundations. (…) The lack of methodological awareness, together with the increasing dynamism of detailed research and natural discoveries, as well as the cooling (for various reasons) of lively philosophical passion, especially in the field of metaphysical issues, caused an increasingly discernible failure to distinguish metaphysics from physics. One must bear in mind the profound, if I may say so, vagueness of the word ‘physics’ in circulation at the time. Physics is still understood as a melting pot in which philosophical reflection on the material world is combined with a whole host of more or less developed and already independent natural sciences" (pp. 30-31).