How realistic are economic models? How can we know what to include or exclude in a model?

What assumptions do economists make when they apply economic theories to the real world?

Many economists argue that economics as a social science is in its infancy, and that with time, as empirical testing methods and the quality of data improve, it will become more reliable in making accurate predictions. Do you agree with this statement?

To what extent does the distinction between positive and normative statements exist in other academic disciplines?

To what extent have individuals shifted the paradigms of economics?