mali said:
It seems nobody is interested in this gedankenexperiment. The consequences would be that reality moves "sideways". The medieval folks didn't know the world is round, but the future observation changed the earth to be round, so it was already round for the medieval folks. Nobody could prove it was not round, because you couldn't reverse this "sidestep" in reality or to be more precise, you can't carry over memory from the parallel thread.
This would mean that reality is a self-stabilising process.
It's not like I'm not interested in the Gedankenexperiment, but rather that I don't understand the rules you're trying to introduce in this abstraction-changing universe.
So you're saying that if someone observes a new aspect of the universe, it not only comes true in that instance, but also retroactively. So if the Earth was flat right now, it would be possible for it to have been round this instant in the future... But how is that relevant for the universe's integrity? You know of the "If a tree falls in a forest and no one is around to hear it, does it make a sound?" problem, right? The same, I think, applies in this case: If no one observed - in pre-antique times - that the Earth was round, did its roundness matter? Did it have an appearance/shape at all?
So one would think that it'd make a difference that the observed changes apply retroactively, but I don't think that that's the case, because it doesn't make sense to introduce another observer retroactively.
And I think I see the dilemma you're bringing up: if person B discovered that the Earth was round, but before that, person A had observed that the Earth was flat, shouldn't the experience of person A be changed retroactively? But, see, the point I'm trying to make is that person A couldn't have seen that the Earth was flat. He'd have been the first to see the shape of the Earth, and would have seen that it's round.
Or expressed differently: before someone saw that the Earth was round, it had no shape at all; before that, it had simply been the ground we walk on etc. so there was nothing that was indicating or that was dependent on that it was round. It then "became" round once someone observed it from a sufficient distance, because the roundness was the only thing that could explain what had happened on Earth thus far (weather, climate, gravity etc)
Interestingly, this system would explain the Photon paradox: A photon stream (ray of light/other radiation) is normally a wave, but once observed it becomes a string of particles, that produces different results int he double-slit experiment and so on. It would be explained by means of this optimization theory: When you look at a beam of light, the universe "optimizes" it into a sine wave. Only when you look closely enough does it become individual particles. The universe then has a "bug" since it makes an observed photon beam behave differently than an unobserved one, but it's at least explainable.
