CHWISTEK, LEON (1884–1944), Polish philosopher. Chwistek lectured in philosophy at the University of Cracow and was later appointed professor of mathematical logic at Lvov in 1930. Working within the brilliant Polish renaissance of modern philosophical and literary creativity during the first third of the 20th century, he undertook original investigations in logic, mathematics, theory of knowledge, aesthetics, and political thought. In his view of the world, which was humanistic and naturalistic, there are pluralities within reality, and for him it seemed clear that any interpretation which saw the world as a single reality would be beset by contradictions. For Chwistek there were at least four realities: the common sense objects of the sort treated by 19th-century British empiricism; the theoretical constructs, typically in scientific theories of the microworld; the realm of sensations and sensed impressions, treated by Hume and Mach; and the no less real world of fantasy, dependent upon men's individual wills. Perhaps his most significant philosophical work was Granice nauki (1935; The Limits of Science, 1948). He exerted a wide influence among students and colleagues within the arts as well as in philosophical scholarship, and among socialist and Marxist circles.
K. Pasenkiewicz, in: Zeszyty naukowe Uniwersytetu Jagiellońskiego, Rozprawy i studia, 38 (1961), 5–146, incl. Ger. and Rus. summaries.