There's something called the uncertainty principle, right, in quantum mechanics. Position and momentum cannot simultaneously be exactly defined. The fact that something is being monitored by the environment in order to allow a quantum mechanical system to act classically implies that you have to pick one position and momentum. So of these possible things to measure, you pick half of them. And that is what those fact though, we call position. We call location in space. You're only allowed to monitor one thing. And that's what wecall position. I think if you want the classical limit, there's going to be a preferred variable and we're going to call that the position.