Scientific realism is the position that scientific theories make true statements about the way the world really is. For many scientists and layman alike, this is the default, commonsense attitude that is typically held towards science and scientific discoveries. Many philosophers, however, hold to a different view of science, often called anti-realism or instrumentalism. Under this view, science makes useful, empirically accurate predictions, helping us to solve problems and interact with the world in predictable ways, however scientific theories do not necessarily correctly describe the way reality ‘really is’. Thus, while realists say that science describes how reality ‘really is’, at least approximately, anti-realists say that science makes useful predictions, even while not necessarily describing the way reality ‘really is’. Note that the dispute does not center on whether science is a useful activity or an epistemologically valid endeavour – adherents of both sides to the dispute are typically ‘pro-science’ in this sense. Rather, the debate centers on what exactly science tells us about the world, and specifically whether it tells us how reality ‘really is’, or merely gives useful tools for making predictions and developing technologies.
One argument in favour of scientific realism is the so-called ‘no miracles argument’, according to which the immense success of science in making predictions and providing the basis for technological advancement becomes an inexplicable ‘miracle’ unless we believe that science actually does succeed in describing the way the world really is. A contrary argument in favour of anti-realism is that all we can truly infer from the empirical success of the sciences is that they are empirically adequate; any deeper inference about the true constituents of reality lies beyond what science can access or say anything directly about. Much more could be said about this complex and often abstract issue, but here it is sufficient to emphasise the importance of the question of scientific realism for determining how one views the relationship between science and philosophy.
What is scientific realism: a short but clear introduction
Realism and antirealism: an introduction to each position from Explorable
Scientific realism: extended discussion and analysis from the Stanford Encyclopedia of Philosophy