You said Newtonian physics isn't the universe we live in. You asked how on earth we can say a particle is in a particular place.
To be clear, I don't really say those things. They are my understanding of what modern physicists say, bearing in mind that I am not a physicist nor do I know much about the subject other than what I read online and in SciAm over the years. But yes, that's my understanding. That the world's not Newtonian, and under some interpretations of QM, a point has no position at all till we measure it.
I'm saying the description of a quantum particle, unlike the description of a Newtonian particle (which has a centre of mass), doesn't even describe something physical.
This is a point of philosophy you need to take up with the physicists. I did link the Wiki page earlier on interpretations of QM.
I'm trying to call you on your apparent claim that QM describes the real universe,
I make no such claim nor have I ever made such a claim. On the contrary I've strenuously argued the opposite many times in this thread already.
QM is known standard accepted physics. That's all I say it is. Some think it describes a real world "out there," others think it only approximates a real world "out there" that we will never exactly know, and still others deny there's anything "out there" at all. These are philosophical issues. I take no position in this thread, although personally I tend toward's #2. There's a world "out there" but it's stranger than we'll ever know. At best we can get better theories that predict experiments to more and more decimal places. The current record is 12, in an experiment of QED.
when it doesn't describe the measurable universe.
Ok by me. Nothing to do with my argument. My argument doesn't depend on QM being true. Don't you realize that nobody knows what QM means? This is a key issue in the modern philosophy of physics. We have this theory that gives 12 decimal places but none of it makes any sense. "Nobody understands quantum mechanics." -- Richard Feynman said that!
I hope you are coming to appreciate this point. We have a theory that predicts but that makes no sense. For a century the smartest people in the world are trying to figure out what it means.
We see 'Newtonian' dots on a screen, we think of momentum and energy, a path through space, because we know where the particle was when it hit the screen at a certain accurately measurable time. QM doesn't describe this dot thing. At all.
Of course for our local conditions, Newtonian physics does quite well. Well enough to send men to the moon, to explain those little bouncing balls on thread things. Here it is, appropriately named Newton's Cradle.
https://www.amazon.com/ScienceGeek-...ocphy=9031303&hvtargid=pla-442521121181&psc=1
And since all physical science is a game of approximation, then any approximation that's good enough for local conditions is fine. But you know, the copies of the master kilogram that are kept around the world, tend to drift over time. Atoms evaporate from the surface even in a high quality vacuum. No physical apparatus is perfect.
Do you feel that I'm addressing or at least understanding your points a little? Of course the world is Newtonian "for all intents and purposes." [Not, "for all intensive purposes," a common misunderstanding and misspelling of the phrase].
But saying that the National Bureau of Standards has a one kilogram bar of pure platinum that defines what it means to be a kilogram, I'm not disagreeing with that. I just don't see what it has to do with anything. The official kilogram in Switzerland or wherever they keep it, is not evidence that a particle, whatever that is, can be in a certain location, whatever that is, measured by an arbitrary real number. You are very very far from making that kind of connection. And honestly, I do wonder why you bring up an example so trivial and off-the mark. Like "Oh are YOU SAYING that because measurement is approximate, I shouldn't teach my kid how a ruler works?" Jeez man, raise the level a bit. Try to hit my brain and not my buttons.
