the reason why the Many Worlds Theory results in such vastly different Newtonian/macro worlds?



I understand that electrons diverge and create new universes. But surely these changes that occur with individual electrons dont result in such vastly different macro worlds? To the point that in one universe Im wearing a clown costume playing water polo because an electron in a laser behaved spun right instead of left.

In: Physics

It takes time for changes to propagate through time and space.

*If* the many worlds theory is correct (we’re not sure that it is), then a lot, maybe most, of potential choices might have no macroscopic effects. It would kind of average out, since not that many quantum effects have directly macroscopic effects.

However…the universe is also generally chaotic…*very small* changes in “initial” conditions can have wildly large impacts if you project them far enough forward in time.

The situation where you end up in a clown costume playing water polo would have had to have been an electron doing something weird possibly hundreds or thousands of years ago, and then slowly cascading effects from there.

To get an “instant” effect you need the situations where quantum effects become immediately observable. For example, bit flips in microelectronics can be caused by cosmic rays, and have caused industrial accidents. And cosmic rays come from *really* far away. So a tiny quantum effect that adjusted the direction of a cosmic ray by a ludicrously tiny amount, multiplied over the very large distance to earth, could easily cause the ray to miss the transistor it happened to hit in our universe. Macroscopic consequences blow up from there.

To make sense of it, it’s important to note that “Many Worlds” is an *interpretation* of the math of quantum mechanics, not a “theory” in the scientific definition of the word.

There are many other interpretations of quantum mechanics that involve no extra universes or alternate pasts or alternate futures.

Separately, the physicist J.S. Bell wrote a paper showing how the “Many Worlds” interpretation converges with the totally separate interpretation of the physicist Bohm, if you remove the philosophical aspects of particle *ontology* from the Many Worlds Interpretation.

At that point, the interpretation is 100% in the realm of philosophy, because it concerns itself with human concepts in a physical *model*, not the underlying physical predictions of the theory.

Max Jammer’s books on the [Philosophy of Quantum Mechanics]( are considered classics in the field, covering the details of non-relativistic quantum mechanics interpretations, with tons of citations to source material.

The electron in question would have split some time ago, but more important, there are very many electrons and other particles. Rather than just two worlds, there’s a smooth continuum of many (possibly infinite) worlds, a small subset of which involve you playing water polo in a clown costume.

* Our college roommates were randomly assigned.

* The roommate I was randomly paired with started a chain of events which lead to me meeting my now-wife.

* If a divergent outcome at the electrical level resulted in the computer picking a different random number, then I got a different roommate at the macro level, which then leads alter-me to have a *completely* different life with different relationships, which also cause going into different professions and living in different places.

Now someone please correct me if Im wrong here.

I think youre a bit too hung up on single individual differences. With the many world theory there is a world for every possible outcome and if theres a large differnce between to worlds its probably not because of a single or a few different outcomes, but because of many different outcomes.

If you take radioactive decay for example. The decay is random, so there would also exist a world where decay isnt happening at all. Just like one possible outcome of a million coin tosses is a million times heads in a row, there is a (really really really really) small chance of the decay not happening for a long time. And with the possibility being there, there would be a world with that outcome.