Look up on quantum gravity (or rather, lack of unified theory with both QM and GR). It is a very complex issue and many basics have to be learnt before it can be at all discussed. The way we do physics right now is by applying inconsistent rules. We can't get QM to work out to GR in large scale. It may gracefully turn 'classical' but this is precisely the problem because the world is not classical at large scale (GR).