Scientific realism is a positive epistemic attitude towards the content of our best theories/models recommending belief in both observable and unobservable aspects of the world described by the sciences. This attitude has important metaphysical dimension. It is committed to the mind-independent existence of the world investigated by the sciences (Chakravartty 2013). In his papers Mathematics and Experience (2009) and Mathematics and Reality (2011) Ladislav Kvasz holds a position of instrumental realism. Kvasz claims that reality is instrumentally constituted and realism issue should be understood as a relation between two languages instead of world-language relation. Kvasz’s instrumental realism also suggests to build up an ontology of distinctions instead of an ontology of fillings. The paper deals with Kvasz’s version of instrumental realism critically and it aims to show that Kvasz’s position is much closer to antirealism than to scientific realism because it does not meet the metaphysical dimension.