But we don't have even a set of definite trajectories. If we see e.g. an electron coming towards a hydrogen atom and then an electron moving away from it, not only do we not know whether the incoming electron "bounced off" or whether it settled into the orbital and "kicked" the electron that was already there out, but in a fundamental physics sense what occurred is some weighted average of both (in the same way that we don't merely "not know" which of the two slits an electron went through but in an important physical sense it partially went through both).