1. This paper is partly based on Ch. XIV of my forthcoming book Logic and Philosophy in the Lvov-Warsaw School, D. Reidel. I would like to express my gratitude to D. Reidel Publishing Company for permision to reprint here some fragments of that book.
2. “Ruch Filozoficzny”, XI, 1928–29, p. 196.
3. Eine Bemerkung über die Struktur logischer Formeln, ‘Ergebnisse eines Mathematischen Kolloqiums’, III, 1931, pp.22–23.
4. The Philosophy of Rudolf Carnap, ed. by P. Schilpp, Open Court, La Scalle 1963, p.31.
5. Zywotne i mniej zywotne koncepcje zadań filozofii (On vital and less vital conceptions of tasks of philosophy), ‘Przegląd Filozoficzny’, XXXIX, 1936, p.366.