Orange6

I’m always skeptical of hypotheses that use infinities like Many Worlds Interpretation and an infinitely big universe, in part for this reason. I wonder if the ideas about the universe being infinitely big are a holdover from the days before the Big Bang was universally accepted. For whatever reason, people couldn’t let go of the idea of an infinitely big universe even as the Big Bang became the consensus, so they came up with the idea that the universe is infinitely big but still expanding. (Which honestly seems like a contradiction in terms to me.)

I’m definitely a skeptic about MWI, but there’s no real proof against it. The ghost analogy for MWI is a pretty accurate analogy, but all that means is there’s no proof MWI is real. Not that there’s proof against it.

MWI would pretty easily get around the energy problem if the net energy of the universe is zero, as some scientists predict. However, I have wondered about universes separating faster than the speed of light. That seems to be what MWI predicts, even though I’ve never seen an MWI supporter outright say that. In any case, QM is very strange, so I wouldn’t say a few counterintuitive things about a theory completely rule it out.

What exactly is the difference between the 2?

Exactly. The probability of any event under MWI is seemingly infinity/infinity, which is an improper fraction.

Copenhagen and MWI are competing interpretations. Copenhagen and MWI both have problems that seemingly aren't very well resolved, as do the more minor QM interpretations. Copenhagen has the problem of defining exactly what an observation is. MWI has problems of probability. (Everything occurs somewhere so how can you assign probability.) All interpretations of quantum mechanics, frankly, are pretty bad. Really, the question is about which interpretation of quantum mechanics is least bad. It currently is untestable which interpretation is correct, and perhaps it always will be untestable.

But if everything (except things that are literally impossible under the laws of science) is bound to happen under MWI, an infinite amount of times, isn't the probability of everything essentially 100%?

Has it really been shown that probability laws would work under MWI? Anything that can theoretically happen under the laws of physics would seemingly have a probability of infinity/infinity of happening under MWI.