Scientific realism is, at the most general level, the view that the world described by science is the real world, as it is, independent of what it might be taken to be. Within philosophy of science, it is often framed as an answer to the question "how is the success of science to be explained?" The debate over the success of science in this context centers primarily on the status of unobservable entities apparently talked about by scientific theories. Generally, those who are scientific realists assert that one can make valid claims about unobservables (viz., that they have the same ontological status) as observables, as opposed to instrumentalism.