What I mean is, how do we know Quantum Mechanics is not some real good approximation to an even better theory about micro interactions? Just like Newtons's Law of Gravitation is just a good approximation to General Relativity. I do not have a problem with Qauntum Mechanics but in order for physicists to unite the two pillars dont we need the right theories? I just want to know what makes physicists so confident that Quantum Mechanics is not just an approximation. Thank you for your time. And about the succesful predictions that we experience today, Newtons Law of Gravitation predicted many things that General Relativity predicts, such as black holes.A theory can be approximate and still make true predictions.