That's not what observable means in a scientific context. You don't have to see something with your own eyes to be able to make an assessment of it. An observation is whatever effect the phenomenon in question has on the world; "things fall down" is an observation. "Biologically reproducing organisms evolve over generations" is an observation. The scientific method is then employed to determine the mechanism of those observations. In science, seeing is not believing; seeing is the start of the investigation, not the conclusion.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'