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Comment by amelius | Hacker News Reader

Locality (as opposed to non-locality) is a strange concept if you think about it. Because how would different points in space "know" to run the same set of equations? Hence all points have something in common, giving rise to the possibility (or non-weirdness) of non-locality. But of course, this is completely non-scientific :)

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Actually it's the other way around. Because of translation invariance we have the law of conservation of momentum. Because of temporal invariance we have the law of conservation of energy. Every symmetry gives rise to a physical conservation law, from which forces can be derived.

See Noether's theorem.

* every differentiable symmetry of an action

(Sorry to be nitpicky, but the asterisk is very important haha)

> Locality (as opposed to non-locality) is a strange concept if you think about it. Because how would different points in space "know" to run the same set of equations?

I'm sorry but I don't understand your point, can you explain it further?

Also one weirdness of QM is not only that it is non-local, it is that it is non-local allowing instantaneous remote 'interaction' BUT without allowing to send information instantaneously (not faster than light).

Well, there isn't much to explain really. Physicists have long had an "intuition" that says that non-locality is somehow a strange concept. However, intuition is often misleading. So I'm flipping the "argument" around and I say that it is more intuitive to think of locality as a strange concept, and to think of non-locality as something which is more natural.

Physicist's "intuition" (as you put it) is educated by codifying our observations into mathematical equations, using those equations to make predictions, and performing experiments to verify those predictions.

Simply 'flipping around the "argument"' is playing with words and has no usefulness from a scientific point of view; it is definitely not "more intuitive" (as you put it) since it has nothing to do with science.

It's an interesting thought exercise IMO. Keep in mind that QM is widely regarded as "counterintuitive" even by scientists, and as far as we can tell, it's the intuitions that are wrong. I.e. it's not QM that's crazy. QM is normal. We are crazy.

> Because how would different points in space "know" to run the same set of equations?

This is not locality. This is translational invariance.

However, equations have parameters.

The principle of locality is that these parameters come from nearby regions of space. Basically, things are only affected by what's near them.

It's violated by quantum mechanics.

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