How do realists and antirealists disagree about unobservable entities?

In the philosophy of science, the disagreement between realists and antirealists regarding unobservable entities—such as subatomic particles—centers on whether scientific theories should be interpreted as literal descriptions of reality or merely as tools for prediction.12

Scientific Realism

Realists argue that science aims for a literally true account of the world. They contend that accepting a theory involves believing its claims about unobservable entities are true descriptions of reality. A primary argument for this view is the "ultimate argument," which posits that the success of scientific theories would be a "miracle" if the unobservable entities they describe did not actually exist. Realists maintain that the best explanation for the systematic success of science is that our theories are at least approximately true.134

Antirealism

Antirealists, such as proponents of instrumentalism or constructive empiricism, argue that theories are merely instruments for generating predictions about observable phenomena. They suggest that scientists should remain agnostic about the existence of unobservables, as the goal of science is "empirical adequacy" rather than truth. Antirealists often point to the history of science, noting that many once-successful theories were later proven false, which they use to argue against inferring the truth of current theories from their success.124