[andrewcooke]

i think you're missing the point? the original question was making the argument, i think, that if the universe is fundamentally non-local, why is almost all physics local?

using an optical analogy: if fourier space is "the real thing", why do we live in a world where point sources are much more common, useful, and interesting, than diffraction patterns?

you seem to be saying in reply "because non-local stuff is difficult to observe". but that's not an explanation; that's the problem.

[although tbh i think you could make this argument against any unified theory - it's effectively the same as "why do we get quantum decoherence?" except that now the idea that it's caused by complexity seems less intuitively right]

[Ygg2]

TL;DR. Theory of evolution meets anthropic principle

I think you are missing my point as well. Reality IS non-local, we just PERCEIVE it as local. No triangle on Earth surface has sum of angles 180, but we say - well it's close enough to 180 so lets say it's 180.

We perceive causality because it's an easier approximation than calculating probability distribution of each molecule. It's like a Russian doll, we perceive the outer doll as whole because we don't look close enough.

Because we don't need to. Evolution didn't specialize us to notice the subtle effect of quantum reality, when a good enough approximation allows us to survive and thrive. We perceive things we perceive, because of their importance for our survival. True nature of reality isn't important to our survival. Thus we don't perceive it.

Reality requires infinite amount of data to process. So we approximate it to stop being overwhelmed.

E.g. geocentric or heliocentric model of solar system are both equally valid. We just choose Heliocentric because its orbits are easier to calculate. Or earth is essentially flat even though it's a sphere etc.

[blueprint]

> We perceive causality because it's an easier approximation than calculating probability distribution of each molecule.

That's not true. Causality is the very mode of operation of the world and it is a requirement for anything to exist at all. Without causality there would be no change and no change means no existence.

Probabilistic models only indicate the degree to which the system is not understood by the observer before his/her confirmation of the system state.

[Ygg2]

Ok, gonna be more specific, but I meant the classical notion of causality. Ball A hits ball B that hits ball C, where each effect occurred in respective chronological order that was given.

Quantuum theory proves that ball A can hit ball B that will travel back in time and hit ball C before ball B was hit. The causality isn't as narrow as in classical physics.

Also another thing to note - that all molecules in any matter move in random direction all the time, as so much their bounds allow them. It is not inconceivable that all molecules of a gold coin could simply move in the same direction and flip the coin by themselves. Chances of gold coins flipping on their own aren't impossible, just very very very very... improbable.

[cscheid]

Sean Carroll talks a bit about this kind of problem here, (albeit when discussing the distinction between "coordinate space" and "momentum space") where we perceive the world in one way, but a lot of physics seems gears towards either one of the worldviews, and the question then is "why the hell?"

http://www.preposterousuniverse.com/blog/2010/11/10/against-...

[andrewcooke]

that's a good point - this is a more general issue than qm. ugh. slideshare is awful [oh; advice to expand to fullscreen makes all the difference. good slides; wish i understood more]

[lotyrin]

Well, a universe with constants that make non-local/relativistic effects common doesn't seem like it would be very good at hosting intelligent observers.

[MacsHeadroom]

>why is almost all physics local?

Do we know that it is? Clearly we are experiencing major observation bias.