The first day of every economics course I teach, I always describe what I call Blurry Brain. I tell my students that they’re going to experience it frequently as they wrap their minds around the abstract theory that is taught in economics class. Some times something will seem very clear but when they look at it again, it will look very strange and they’ll experience Blurry Brain. Eventually, however, things should click for them as long as they stick with studying it.
In order to make it all easier, I start teaching an abstract concept and model by telling a very intuitive story. At the root of all good theory is a story and it should make sense at the intuitive level. Theory should reflect common sense. After that, I explain we have to take some thing that is very intuitive and put into a place where we can study and poke at it like a scientist with a stick and a frog. However, we don’t have frogs and sticks in our economics laboratory. Physicists don’t have those things either. We only have numbers and math relationships. We have to take these very intuitive ideas and make them testable or we can’t prove if we have a valid theory. If we don’t have theory, then we don’t have those common sense stories that guide our understanding of the world.
Theories must be testable so that they come from hypotheses that can be proved or disproved. That is why evolution is a theory. It is testable and has been proved over and over. God is an idea that can never be proved or tested. God has to stay a hypothesis in terms of the scientific method because we can’t empirically test the existence of a ‘god’. Some folks try to infer god, but when it comes to science, you pretty much have to stay within the realm of things that can be deduced from data. If you can experience the data directly, you can test the idea or hypothesis, you can prove it true or false, and you can contribute to theory.