ABSTRACT. There’s an essential methodological and theoretical difference between abstraction and idealization hardly remarked by the main founder of the so-called Poznań School, that’s to say the Polish philosopher Leszek Nowak (1943–2009). Nonetheless, Idealizational theory of science has never been considered the way it deserves, although a lot of philosophers of science nowadays are taking into account this original scientific approach. The aim of this paper is to give a presentation of Idealizational theory of science in order to put in evidence the mistakes of the Popperian interpretation of Marxian philosophy and of the classic Hempelian approach based on the famous D-N model. pp. 125–149

Keywords: abstraction, D-N Model, Hempel, Idealization, Nowak, Popper