4 ms·

https://physics.stackexchange.com/questions/403574/what-situations-in-classical-physics-are-non-deterministic https://physics.stackexchange.com/questions/403574

https://physics.stackexchange.com/questions/403574/what-situations-in-classical-physics-are-non-deterministic https://physics.stackexchange.com/questions/403574/what-situ... Non deterministic dynamics occurs in Newtonian physics as well. These things are worrying philosophically, but we can take some comfort in that the initial conditions for which these occur are "measure zero" i.e. if you were defining a probability measure over initial conditions, then the non-deterministic initial conditions would have measure zero. It doesn't sound like we have that option here though. But in my view, this result is good news. We knew GR was unphysical anyhow. Now we've increased our understanding of how unphysical it is, potentially ruling out more replacement theories.

codethief 5y ago
> We knew GR was unphysical anyhow. We did? That is news to me. Would you mind elaborating?
- algon33 5y ago
  My statement was too strong. By "knew" I meant that it was pretty likely that strong cosmic censorship wouldn't work out [1]. In addition, I think QFT and GR are both probably broken in some way given that they're incompatible and that no one has coerced one of the theories into working with the other. That feels like evidence that the problem is not as simple as just rejecting QM or GR to me. But again, calling that "knowing GR is unphysical" was too strong a statement. [1]https://en.wikipedia.org/wiki/Cosmic_censorship_hypothesis https://en.wikipedia.org/wiki/Cosmic_censorship_hypothesis