3 ms·

The point is that it's unstable even in the Platonic ideal. That's the surprising part.

lisper 3y ago
Well, yeah, but my point is that it shouldn't be surprising. If you think about it, if it is even possible to bring a particle to rest for a finite time in the Platonic ideal then that plus time reversal necessarily entails non-determinism. So non-determinism should be no more surprising than the fact that it is actually possible to bring a particle to rest for a finite time. I think the only reason this example surprises people is that everyone just assumes that bringing a particle to rest is possible/easy without really thinking through what this would actually require in the Platonic ideal. It's actually very challenging to stop things from moving without friction.
- ShamelessC 3y ago
  You're just reframing the article as though it's obvious and then claiming that it is obvious. The problem is - the article already does just that. Further, you have changed your stance from one of "of course it moves from some noise in the environment" to one more closely resembling the article's main points. You basically aren't making sense. Your initial abuse of "platonic ideals" is the sort of thing that gives philosophical arguments a bad reputation.
- crazygringo 3y ago
  > then that plus time reversal necessarily entails non-determinism. No. Generally speaking in the "Platonic ideal", we assume that if we reversed time, the particle would move from rest in a deterministic way, that there's only one solution for its movement. The surprising part here is that there are multiple valid solutions. Which takes a very-specially designed "dome" to demonstrate -- which is very surprising indeed. > It's actually very challenging to stop things from moving without friction. No it's not. All it takes is a billiard ball in motion hitting another billiard ball at rest. The first billiard ball will now have stopped moving. Which is kind of the canonical example of how we expect things to be deterministically reversible.
  - lisper 3y ago
    Yes, you're right, and this occurred to me after I posted but while I was in the shower so I couldn't correct it :-) I should have said "if it is possible to bring all of the constituent particles in a system to rest for a non-zero time..."

Well, yeah, but my point is that it shouldn't be surprising. If you think about it, if it is even possible to bring a particle to rest for a finite time in the Platonic ideal then that plus time reversal necessarily entails non-determinism. So non-determinism should be no more surprising than the fact that it is actually possible to bring a particle to rest for a finite time. I think the only reason this example surprises people is that everyone just assumes that bringing a particle to rest is possible/easy without really thinking through what this would actually require in the Platonic ideal. It's actually very challenging to stop things from moving without friction.

ShamelessC 3y ago
You're just reframing the article as though it's obvious and then claiming that it is obvious. The problem is - the article already does just that. Further, you have changed your stance from one of "of course it moves from some noise in the environment" to one more closely resembling the article's main points. You basically aren't making sense. Your initial abuse of "platonic ideals" is the sort of thing that gives philosophical arguments a bad reputation.
crazygringo 3y ago
> then that plus time reversal necessarily entails non-determinism. No. Generally speaking in the "Platonic ideal", we assume that if we reversed time, the particle would move from rest in a deterministic way, that there's only one solution for its movement. The surprising part here is that there are multiple valid solutions. Which takes a very-specially designed "dome" to demonstrate -- which is very surprising indeed. > It's actually very challenging to stop things from moving without friction. No it's not. All it takes is a billiard ball in motion hitting another billiard ball at rest. The first billiard ball will now have stopped moving. Which is kind of the canonical example of how we expect things to be deterministically reversible.
- lisper 3y ago
  Yes, you're right, and this occurred to me after I posted but while I was in the shower so I couldn't correct it :-) I should have said "if it is possible to bring all of the constituent particles in a system to rest for a non-zero time..."