Anti realism gives solutions to interpretation al and philosophical problems in science. It explains the "Luck of causes" in hypothesis, un observable entities and it providers alternative to issues in QM foundations.

The 3 subsets of anti-realism in science

Instrumentalism can be deemed to be a subset position of anti-realism with a particular relevance to science. It is a pragmatic approach.

For the instrumentalist, theories are seen as instruments which deal with what is observed in experimental situations. Thus theoretical terms (or concepts) are also deemed to be “fictions” which are instrumentally useful to scientists

Subset 2, truth sidelined, comes from a theologician's quote it can be seen that there’s a clear separation between what he (Osiander) called “observation” and what he called “the true causes” of those observations. Indeed it was said earlier that the notion of truth is sidelined by anti-realists. So here we have Osiander saying that Copernicus’s “hypotheses need not be true nor even probable” if “they provide a calculus consistent with the observations that alone are sufficient”.

A 3rd subset compatible with antirealism is the position called “semantic instrumentalism”. In other words, the terms used in quantum mechanics aren’t taken as referring to literal entities. Instead, such terms are “logical constructions” (a term first used by Bertrand Russell) which are employed to make sense of the things we can indeed observe.