- If your theory predicts nothing then it is not explanatory, for all it does is restate your existing observations.
- If your theory is just a reference to (or placeholder for) a theory you don't have, then it isn't explanatory. You cannot explain merely by declaring what you would name an explanation if you had one.
- If your theory is predictive, but attributes the prediction to an entity you know nothing about, then the entity in question is not part of the explanation.
Gravitational force is proportional to inertial mass.
This theory makes many predictions, so it is an explanatory law. However, if you attribute this force to an "Unknown Theory of Everything" then your Theory of Everything isn't adding any explanatory power. If you say Unknown Theory of Everything causes Gravitational force to be proportional to inertial mass, then you're not explaining any more than you did with your original theory.
At random, God strikes sinners with lightning. We are all sinners, and all guilty in the eyes of God.
This theory isn't predictive, so it explains nothing. Furthermore, its ridiculousness is exposed when we substitute "Unknown Theory of Everything" for God: At random, Unknown Theory of Everything strikes some sinners with lightning.