Physics, Astronomy & Cosmology / Re: What happens when both slits are observed by in the double slit experiment?« on: 08/11/2019 22:51:58 »
@Halc This is worth a read.Interesting link. Yes, it says that Newton envisioned a classic billiard-ball sort of physics, and it was that way all the way down, and relativity didn't really challenge that (except maybe it does, as the article points out).
Quantum mechanics definitely threw a wrench into the works for the determinists, but it as well doesn't disprove it since there are very much deterministic interpretations of QM.
I think we'd need a unified field theory to begin to say whether relativity has any concrete stance on the issue.
From the article:
Quote from: Cartlidge
Newton’s mechanics allow us in principle to calculate the exact state of a physical system at any point in the future, provided that we know its initial state perfectly. So too with general relativity: a precise knowledge of space’s geometry and its rate of change in the present enables us in theory to predict exactly how space-time will evolve.This is clearly false, and known to Einstein at the time. QM theory says no amount of measuring of a system will allow you to predict it. Einstein was definitely a determinist, as evidenced by his "God doesn't throw dice" quip, but I don't think any of the deterministic interpretations where developed or well known at the time. There was the 'hidden variables' postulate which said there are variables which cannot be known, but if they were, the future would be perfectly predictable.
As such, Einstein’s theory is considered by most physicists to be entirely deterministic.... as it doesn't contradict Newton's 'classic all the way down' assumption. But the theory also doesn't posit this assumption. It merely declines to challenge it. QM very much challenges it.
Charged black holes, however, challenge this deterministic picture. The “Reissner-Nordström” solution of general relativity describes a black hole created when a star that is electrically charged and spherical collapses in on itself under the force of gravity. Hidden from view inside such a black hole’s event horizon lies a second boundary known as the Cauchy horizon, beyond which space-time is smooth but indeterminate. In other words, the future can no longer be predicted.It has also yet to be demonstrated that it is meaningful to speak of the physics inside the event horizon. It is mathematically infinitely far into our future, and since the black hole will evaporate in finite time, it is questionable if anything 'gets in' so to speak. Again, a unified theory would help. The subject has proponents on both sides, and this would best be discussed in a separate thread. I'm quite opinionated on it myself, having the luxury of not completely knowing what I'm talking about.