First and foremost, I would just like to say that I have limited familiarity with quantum mechanics and virtually no familiarity with string theory, so this is quite a shot in the dark, but I'm hoping someone here who is more knowledgeable will tell me what they think of the idea I'm about to propose. When I was recently pondering string theory I thought about the idea that there might be several dimensions that we cannot see, curled up in ultra-microscopic spaces. Then I started thinking about the sub-microscopic world and quantum mechanics. Is it possible that these sub-microscopic dimensions that we cannot perceive are responsible for the quantum randomness that we observe at the sub-microscopic level? Isn't is possible that these dimensions could appreciably affect the path of a sub-atomic particle? They wouldn't affect the path of a large object (which is why we perceive the macroscopic world as being deterministic...quantum mechanics doesn't play a significant role), but they could have an effect on a particle. Since we can't detect these dimensions, we cannot determine the effect they would have on a particle, hence we get the uncertainty characteristic of quantum mechanics.