No, once again, it *is* a proven idea. We have actual observations of the effects of particles being produced spontaneously out of a vacuum.Ex nihilo, nihil fit is every bit as logical as it has ever been. You want to simply sweep it aside, claiming it is invalid and you base it on something you admit is nothing but an unproven idea. That my friend is a perfect description of blind faith.
Newton's first law is dead in this context. Heisenberg's principles and quantum mechanics show it is wrong. These are NOT speculative ideas. They are well verified science that is the foundation of much of modern technology.The same goes for Newtons First Law of Motion.
An easy way to see it is wrong. A particle at rest has a perfectly well determined momentum (it is zero). By the uncertainty principle, the position of that particle must be completely undetermined. It must be evenly distributed over ALL of space. That is impossible in practice, so it is impossible for a particle to *stay* at rest in quantum mechanics. This happens even without an external force producing an acceleration.
And, again, I want to emphasize that this is NOT speculation. Unlike string theory, quantum mechanics is not speculation. It is well tested and is accurate.