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Comment by IgorPartola | Hacker News Reader

Here is what I don’t get, and never did as a physics undergrad: why is the information transfer important here?

Let’s modify the thought experiment: Wigner’s friend measures the photon’s polarization and determines that it is horizontal. He then calls Wigner on the phone and tells him the result. Does this affect the result that Wigner sees when he verifies superposition? What if the friend lies? The post you linked seems to specifically call out that the friend cannot reveal the result of his measurement, lest the experiment get spoiled.

This all seems to point to some philosophical/theological Mumbai jumbo with regard to consciousness being a necessary ingredient here, which doesn’t hold water. Yet with every thought experiment like this that I have seen, this kind of clause is included. Can anyone explain it like I am 25?

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"Mumbai jumbo"?

On the road to Damascus and enlightenment, stunned by a bystander's use the term "Mumbai jumbo", Paul fell off his horse and into the stones beneath a set of railroad tracks. Upon reaching consciousness again he saw an old man who extended a hand, smiling, nodding and, speaking the phrase "mumbo jumbo" re-assuredly and repeatedly, helped Paul to his feet.

I think it’s more of a new dance move but I like your parable nonetheless.

Mumbai is the new Cupertino?

https://en.wikipedia.org/wiki/Cupertino_effect

The video in the comment you replied to is excellent I think. And it doesn't involve any sort of hand waviness (theological implications) in the final description. Basically just having machines accurately measuring the photons changes the results (e.g. vs. the machines measuring the photons, but scrambled so they can't recover the information). So it's definitely a property of attempting to recover the information, regardless of how it is measured or reported, which is weird, but doesn't have any sort of consciousness involving implications, because it happens to machines as well.

It's definitely worth the 10 minute watch if you want it explained to you.

The field's (quantum physics') moving back and freely between: Serious Math; ill-advised specialist terminology that borrows then twists common words in just the worst ways; and seemingly metaphysical stories or explanations that are... literal? Metaphorical? Full of borrowed BS words from point two that fall out of the math but don't "mean" anything in everyday terms? Definitely one of those until you ask a question then you're an idiot and it's another, until it's not again? Has put me off any childlike interest I once had in it. It seems fun. But I can't tell when they're serious or screwing with me. Sometimes one person claims something's serious, and they do so with authority, and another says they're screwing with me with just as much authority. I gave up.

Somewhat relatedly[0], I can't find an explanation of the Oberth Effect that makes any damn sense. Every so often I try again and leave disappointed. People are happy to provide them. There are lots of them. They attribute it to all sorts of things. Not one of them I've read makes sense.

[0] i.e. is physics, but is not quantum physics. So far as I know, anyway.

>I can't find an explanation of the Oberth Effect that makes any damn sense.

It's simpler than people make it. When a spacecraft is moving at a high velocity, the amount of kinetic energy embodied by its fuel mass is a significant fraction of the chemical energy already present. And kinetic + chemical is greater than chemical alone. That's all there is to it.

> I can't find an explanation of the Oberth Effect that makes any damn sense

I'll take a crack at it:

Kinetic energy plus gravitational energy is conserved when you aren't actively accelerating[0]. Rocket fuel has kinetic and/or gravitational energy in addition to it's chemical energy. If you burn the fuel while going very fast[1], you can extract it's kinetic energy by bringing the exhaust to(wards) a stop. When going slowly[2], you end up spending energy to accelerate the exhaust away from you, and you also can't really do anything to get at its gravitational energy[3].

0: Ie, thrusting your engines or crashing; things that involve g-forces; not freefall.

1: That is, when most of its gravitational+kinetic energy is in kinetic form.

2: With energy mostly in gravitational form.

3: Gravitational energy is a function of where mass is at that exact moment; if you're high away from a gravity well, you have lots of energy tied up as gravitational, and no quick way to turn it into a more useful form.

To be fair, "quantum physics" is much too broad a brush here, your issue is with "quantum interpretations" or something -- I'm not sure this subfield has a really firm label. But it's fully of people tripping over paradoxes they invented and encouraging you to likewise stumble and admire how cleverly they tried to disguise their handiwork. In content it's unclear we've learned anything new here in the last 50 years.

But straight "quantum physics" covers lots of other, more solid, areas. Including understanding how lots of things you can actually manufacture work, like semiconductors and superconductors.

https://en.m.wikipedia.org/wiki/Quantum_foundations

If Wiegner knows the outcome he has no reason to use the entire superposition formalism of quantum mechanics as there is no uncertainty to constrain.

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