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How would you define exactly ‘when gravity starts playing a role’. It always plays a role, from photons to planets.

And on the ‘every tick creates more universes’: we are completely fine with superposition in nanoscopic systems. It’s just uneasy to follow that conclusion to the logical end. Just my two cents. I think just because the conclusion seems hard to grasp, the reasoning to get there is completely sound..

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“Starts to play a role” means when the effect of gravity becomes significant to the quantum equations which currently don’t have any placeholder for gravity.

Just like Newton’s equations are accurate to describe gravity and motion but only because the full equations Einstein worked simplify to them at small speeds.

So similarly it would make more sense that quantum equations and relativity are two sides of the same coin and there’s some missing mathematical bridge where at small particle sizes it simplifies to quantum and at large particle scales gravity matters and we get Newton and then further relativity.

Using Occam’s razor that’s at least my prior vs some undefined mechanism of action where all possible interactions of every particle actually creates an infinite superposition of universes where that did happen and you get an infinite number of such superpositions ad infinitum. Much easier to believe the huge gaping hole between two very accurate theories explains how quantum mechanics turns into classical mechanics, especially since we know gravity exists, what it is, and quantum mechanics can’t explain gravity.

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The place where quantum and gravitational effects are thought to become significant to one another is at energy levels that cannot be obtained in our experiments, either in the lab or through astronomical observation.
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And so as a result there’s multiple worlds? That’s the simpler more testable prediction?
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I'm just an old industrial physicist, but as I understand it, quantum gravity has yielded no testable predictions so far, and neither have multiple-worlds theories.
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I never said anything about quantum gravity. String theory is also trying to bridge things. But many worlds is pointing to a gap in the math and claiming god. All I’m saying is we don’t have any model or math and many worlds is the more fantastical explanation.
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It's simple and elegant if you like it, overcomplicated if you don't.
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Many worlds is a philosophical interpretation akin to god. It doesn’t add anything to our understanding and instead invokes some kind of supernatural untestable phenomenon.
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This is more or less Roger Penrose's position: https://web.archive.org/web/20150327124054id_/http://image.s...

He argues that the wavefunction collapses on a timescale of h-bar / E_G, where E_G is the gravitational self-energy of the quantum system.

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Didn’t know this but glad I’m in such distinguished company.
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