EN
This short paper is devoted to questions concerning the essence and role of cognitive values whose realization is deemed a guarantee of the rationality of science. In this context, the author quotes theses formulated (in philosophy of science) by different authors (Hacking, Walczak) - expressing the positions that defend the idea of scientific rationality (e.g. logical empiricism and critical rationalism) as well as those that undermine it (e.g. historical and sociological relativism) - and identify cognitive values connected with particular theses. In the final part of the paper, encouraging to the discussion concerning cognitive values in science, he suggests a reflection on the problem whether a descriptivist or a expressivist evaluative terms meaning conception works in favour of any of the sides in the philosophical issue about scientific rationality.