While the realist accepts that unobservable phenomena do exist and does not consider a theory to be a fact but merely as approximately true. .
James Robert Brown of the University of Toronto is a realist. Realism, as affirmed by Brown, is determined by scientific success, which is best determined by theories that, first, "are able to organize and unify a great variety of unknown phenomena." (Brown, p.133). Second, latter theories systemize data more accurately than former, lastly and most importantly " a statistically significant number of novel predictions pan out," (Brown, p.134). In his work, explaining the success of science, Brown tries to describe scientific success whilst defending scientific theories by contesting anti realist ideas. Throughout the paper he mentions various anti realists along with their work regarding the succession of a theory. Bas Van Fraassen, one of most influential anti realists, suggests that it is not at all surprising that theories are successful, given that any unsuccessful theory is rejected. He believes that the success of science happens purely due to chance, or coincidence. Fraassen tries validate his view through Darwinian natural selection. He says that just as species struggle for existence, so do theories. Species who do not adopt to their environment become extinct, "so too are theories which do not make true observational predictions dropped" (Brown, p.134). A theory looms closer to approximating the truth through constant research, probing and analysis. Brown acknowledges the fact that theories sometimes get reworked and even discarded to achieve this scientific progress. Although not entirely wrong, Fraassen's rationalization accounts only for the first two features of scientific success, whilst ignoring the third attribute, regarding the accuracy of scientific predictions. "The third question is still unanswered" (Brown, p.