I guess I’ve always been confused by the Many Worlds Interpretation of Quantum Physics and the fact that it’s taken seriously. Like is there any proof at all that universes outside of our own exist?
I admit that I might be dumb, but, how does one look at atoms and say “My God! There must be many worlds than just our one?”
I just never understood how Many Worlds Interpretation was valid, with my, admittedly limited understanding, it just seemed to be a wild guess no more strange than a lot things we consider too outlandish to humor.
Well, under Many Worlds, wave function collapse isn’t a real “thing”; it’s just an illusion caused by the observer becoming entangled with the wave function. Objective Collapse theories, however, propose a real physical mechanism of wave function collapse. If that’s true, and there was found to be a real mechanism of collapse, then MW would be impossible, because the wave function would collapse before any “branching” could happen.
And what is there to stop the collapse from being the branch point? In one world, it collapses one way; in another, another. There doesn’t seem to be any inconsistency there.
Well, because under Many Worlds, the wave-function not collapsing is the reason there are multiple branches; the wave function is the multiverse. So if the wave function has collapsed into a single, definitive state, then there is only a single, definitive universe.
Sorry, that doesn’t prove that there’s not actually Many Worlds out there. The whole point is that there would be a single, definitive universe state for every possible valid configuration after wave-function collapse. The reason it’s unfalsifiable is that it cannot be proven currently whether or not it’s a literal plurality of alternate worlds. I would also argue that if there’s but one “definitive universe” state then it’s not really a Many Worlds theory at all, but just a different theory of the Universe.
I’m not saying you’re wrong, or that this interpretation of Many Worlds is wrong - I’m just saying we’ve not yet developed a way to prove it one way or another. And if we did develop that technology to prove it one way or another, that would in itself unlock a whole new world of questions to answer. Thinking about what those questions might be is worthwhile science, in my view.
I think you misunderstand me. I’m talking specifically about the Many Worlds interpretation of Quantum physics specifically, the one originally formulated by Hugh Everett. I’m not talking about just some general notion that “there might be other universes”.
It’s just an indisputable fact that the MWI requires their to be no wave function collapse, and if you don’t understand why, you really have not learned enough about it to be in a position to declare it “unfalsifiable”.
Well, I did allow for that earlier. I’m not a physicist. However, I wouldn’t be so sure I don’t understand why. Reading back over the thread as a whole, you’re right - I did misunderstand you. Let me put it in my own words for you:
But you said above:
and
Could you link the experiments which have definitively shown objective collapse and not just an entanglement illusion? Fair warning, I may need to ask for a layman’s explanation of how they proved the collapse was objective and not just the aforementioned illusion.
Essentially, yes. I think the important point is that MWI is only concerned with the multiverse that an uncollapsed wave function represents, not any other kind of multiverse that might exist in science or philosophy.
Here’s a reasonably good article about them.. But to try and give a short explanation, the experiments were for a class of objective collapse theories were individual particles collapse spontaneously with a certain probability, and take any particles they’re entangled with with them. The probability of any one particle collapsing at any given time is extremely low, but a macroscopic collection will collapse almost instantly, in the same way a uranium atom will take millions of years to decay on average, but a chunk of uranium sitting on a table will make your gieger counter sound like it’s full of bees.
The important part though, is that - for reasons that are quite technical - the collapse of the particle actually emits a small but measurable amount of radiation, which is what the experiments were looking for.
To be clear, they didn’t find it, which is bad for these theories. But if they had found it, it would have falsified Many Worlds.
Funnily enough, I found that article while reading up on MWI and was keeping it in my back pocket to compare with whatever you ended up linking.
So here’s where I think we’re getting tripped up. You’re talking as though detecting this radiation would have falsified Many Worlds; I still think it would not. It would have created an explanatory burden on proponents of MWI, to explain where this radiation is coming from if not wave function collapse. These experiments wouldn’t have been able to prove that the collapse was causing any kind of radiation emission; only that radiation emission was concurrent with it. We could conclude the collapse was the source only if all other sources were ruled out as possibilities.
Here’s why: Each “world” would observe its own collapse of the wave function. The parameters of the emitted radiation - particle or wave type, energy level, charge, spin, colour, direction of travel, everything - would be different for every collapse, because every collapse is a branch point for a new world that can observe that specific collapse.
The trouble here is that you’re taking the “objective” in “objective collapse” at face value. No experiment has been performed that has detected this radiation being emitted, but if it had, it still wouldn’t have falsified MWI. I’m quite sure there’s no experiment that can be performed that can’t also be explained away with branching paths. Certainly not an experiment possible with current technology or theories.
The problem is, as I said, one of perspective:
Both frameworks ultimately make identical (observable) predictions from within each world, which is what makes MWI unfalsifiable. If you had a way to definitively show from within this world that MWI’s other worlds don’t actually exist, then it’d be falsifiable. The ontological claims of a theory are not what make it unfalsifiable.
Ok, well now you’ve basically argued that falsification in general is impossible, for anything. Just like geocentrists could always add more epicycles to explain the motion of the stars, any theory can add more post-hoc explanations for any observations. This isn’t a standard you would apply to anything else, so I don’t know why you’re applying to MWI.
No they wouldn’t, the laws of physics still apply
And why shouldn’t I?
Yes, but by your standard, nothing can ever be falsified.
You asserting it doesn’t make it true.
Except there is no radiation emission unless the wave-function objectively collapses. That’s the point.
No, they don’t. One predicts spontaneous radiation release, and one doesn’t.
literally asking to prove a negative.