Scientific realism is the view that the universe described by science is real, regardless of how it may be interpreted. Within philosophy of science, this view is often an answer to the question "how is the success of science to be explained?" The discussion on 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 unobservable (viz., that they have the same ontological status) as observables, as opposed to instrumentalism. There seems to be a common core of ideas, typified by an epistemically positive attitude toward the outputs of scientific investigation, regarding both observable and unobservable aspects of our universe.