Quantum Computers are transistor computers, except all at once.
All things are true, false and unknown, until they are observed. Answers are only opinions, but infinite opinions approach truth arbitrarily closely. A race against entropy; how much can you calculate in the blink of an eye? Even that is too long to be certain. Useful quantum computation is a compromise between reality and everything else. The more practical an approach is, the less likely it will be right. Miracles are correct, but impossible. Luckily, perfection is over-rated. Each thing contributes to and is shaped by an influential whole consisting of connections spacial, temporal and quantum. Neither individuals nor the whole can be described without describing the other. Grasp this, along with linear algebra, and you begin to understand.