How does instrumentalism view scientific theories differently from scientific realism?

In the philosophy of science, the debate between scientific realism and instrumentalism centers on the purpose and status of scientific theories.

Scientific Realism
Realists argue that the goal of science is to provide a literally true account of the world. They believe that accepting a theory involves committing to the existence of the unobservable entities (such as electrons or subatomic particles) described by that theory. For realists, the success of science is best explained by the fact that our theories are true or approximately true descriptions of reality.12

Instrumentalism
Instrumentalism views theories not as descriptions of reality, but as useful tools or "instruments" for organizing experience and generating predictions about observable phenomena. Key differences include:13

• Truth Value: Instrumentalists often argue that theoretical statements lack truth value—they are neither true nor false—because they function merely as rules of inference rather than factual claims.12
• Utility vs. Reality: While realists prioritize accuracy in describing the natural world, instrumentalists prioritize empirical adequacy, simplicity, and problem-solving reliability.13
• Unobservables: Instrumentalists contend that theoretical terms are convenient fictions or mathematical devices rather than references to actual, hidden entities.32

Ultimately, while realists see theories as maps of reality, instrumentalists see them as navigational tools.3