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Why Quantum Mechanics?

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Re: Why Quantum Mechanics?

#101

Post by EMM_386 »

rep_lodsb wrote: post #38
EMM_386 wrote: post #24

Earlier quoted context omitted.

I strongly feel that the mystery of consciousness is somehow deeply tied into why we have things like QM and not classical physics. If it was just classical physics, then you get yourself into the thinking that you can rewind time and all the "billiard balls" knock into each other the same way, which is why you order a soup and not a sandwich every single time on that day. That eliminate free will. There is something…

IMO the concept of free will doesn't make sense, at least not without also believing in the existence of a soul. If you were to make a decision that is not in some sense pre-determined by the structure of your brain (as shaped by biology and past experiences), it would be essentially random and just as meaningless as an uranium atom "deciding" to decay at some specific moment and not another.

Free-will fits perfectly fine into the evolutionary theory.

When prey are faced with predators on the open savannah, they may be in "unconscious mode" when grazing the grass, but if they glimpse a predator, ears and tail go up, head swings, and they have to make a decision.

Re: Why Quantum Mechanics?

#102

Post by ogogmad »

lordnacho wrote: post #47
chaxor wrote: post #17

Earlier quoted context omitted.

Right hand rule only works in 3d and 7d

That is rather fascinating, where can I read about this?

Given a cross product in n dimensions, it's possible to construct a normed division algebra in n+1 dimensions. Hurwitz's theorem says that the only normed division algebras are the reals, complexes, quaternions and octonions. So there can be no cross products outside of 0, 1, 3 and 7 dimensions.

In computing applications, if you want to find a vector perpendicular to two or more vectors outside of 3 and 7 dimensions, you would use the QR decomposition to do it. If on the other hand, you want to generalise the "directed area" properties of the cross product, you would use Exterior Algebra, or its elaborations like Clifford Algebra or the theory of differential forms.

Re: Why Quantum Mechanics?

#103

Post by [deleted] »

deltaonefour wrote: post #3

The answer to these questions is one of those things that are beyond human understanding. It's like asking why does probability work? Why does predicate logic work? They are axioms. We have never looked beyond these axioms nor will we ever in your lifetime. I mean we may find a deeper mathematical model for quantum mechanics but the question of "why?" will never be answered. It may not even be the right question.

[deleted]

Re: Why Quantum Mechanics?

#104

Post by pyentropy »

guerrilla wrote: post #72
feanaro wrote: post #65

Earlier quoted context omitted.

The fact that your process knows about and is able to comprehend and reason about its own workings gives it the opportunity to change itself based on this knowledge. To hear about it and to then decide "this absolves me of any guilt, because I couldn't have done it any differently" is also a choice your process made. Counterfactually, it could've made the opposite choice (though it didn't do so). Now, me pointing thi…

Why do we absolve some people of guilt for being a product of their genes and environment and not others? Where do you draw the line? It would seem that "they couldn't help it" just as much as the people that you describe.

... because it's a good idea?

If a person with Tourette's said profanities to you during your Zoom meeting, would you hold them equally responsible as a person not having it? No, because it's a symptom and you assume it is out of their control and they didn't have a malicious intent. If both persons said "sorry it wasn't in my control", you'd think

1) the person A didn't do bad, because they have a tic and they definitely don't have negative feelings towards me

2) the person B has an anger management issues and may or may not have negative feelings towards me, maybe he's bad

We assume intent is malicious when a person has the capability to stop themselves from doing something negative towards us and yet they "chose" not to.

A CPU that doesn't work when power is off could be a good CPU, but a CPU that doesn't work when power is on is a faulty CPU.

Re: Why Quantum Mechanics?

#105

Post by MattPalmer1086 »

EMM_386 wrote: post #95
MattPalmer1086 wrote: post #41

Earlier quoted context omitted.

Physicists don't largely choose physical theories on whether they make life meaningful or not. I think you're thinking of religious people.

> Physicists don't largely choose physical theories on whether they make life meaningful or not. I think you're thinking of religious people. I disagree, I think quite the opposite. Physicists often seem to adhere to a "religion" of sorts, that being atheism. Anything to get rid of the "God problem". It's not all so cut and dry. > “I believe in Spinoza's God, who reveals himself in the lawful harmony of the world, no…

There are many religious physicists. I won't get into the argument about whether atheism is a sort of religion.

But even if fervent atheist physicists are trying to remove the God Problem, how does that mean they are selecting physical theories to make life meaningful?

Re: Why Quantum Mechanics?

#106

Post by dojitza1 »

galaxyLogic wrote: post #83

There is a simple answer to the proposed question(s): Parallel Universes. Some of them might have classical physics only.

I'd go as far as to offer an explanation like this: The universe/multiverse is infinite in every (by our brains) comprehensible and incomprehensible form. Both on a macro and a micro level. Our existence is finite in nature, both in space dimension (objects have edges) and time (they change form). It is understandable we have trouble interpreting some of the rules of our universe that we are unable to comprehend. I say quantum mechanics (and perhaps natural science in general) are our attempt to make sense of something fundamentally not comprehensible.

Re: Why Quantum Mechanics?

#107

Post by bondarchuk »

jiggawatts wrote: post #96
dskloet wrote: post #82

Earlier quoted context omitted.

You'll be convinced once you understand the EPR paradox and Bell's inequality. So look those up if you want to be convinced.

I did, and they make perfect sense if you look at them through the lens of MWI, which however seems weirdly unpopular in QM circles. I was taught the Copenhagen interpretation, which is just... madness.

Which interpretation seems to make the most sense depends a lot on the framing of the explanation, and not very much on the experiments themselves. This comment [1] really drove home the Copenhagen interpretation for me, I quote:

>It's painfully easy to have a clear intuitive picture of quantum physics. You just have to ditch one concept.

>Universe is not made of little balls.

[1] https://news.ycombinator.com/item?id=29756842

Re: Why Quantum Mechanics?

#108

Post by ngcc_hk »

robbedpeter wrote: post #30
seiferteric wrote: post #15

Earlier quoted context omitted.

I think the question of free will is even simpler. It doesn't come down to determinism vs indeterminism because either way it's not "you" making a decision. At the lowest level (neuron or whatever) when a decision is "made" it is either deterministic (determinism) or probabilistic (indeterminism) based on physics but either way, where is the "you" in the process? Only way free will makes sense is if something superna…

It's not that easy, unfortunately. The problem lies in the relationship between a mind - the system of patterns of connections and processes that constitute whatever it is that allows a subjective experience to occur as an emergent property - and the external world. That singleton which has experience, and the infinite outside which it experiences. Free will could be framed as unpredictable behavior arising from the…

You cannot replicate exactly. The essence of qm is not q but the uncertainty principle. The mix of both classical works after “collapse” and the so called underlying infinity reach complex number world is not a or b but a and b somehow together.

The @and@ part may answer the free will question. Not the a or b part alone.

Re: Why Quantum Mechanics?

#109

Post by guerrilla »

pyentropy wrote: post #104
guerrilla wrote: post #72

Earlier quoted context omitted.

Why do we absolve some people of guilt for being a product of their genes and environment and not others? Where do you draw the line? It would seem that "they couldn't help it" just as much as the people that you describe.

... because it's a good idea? If a person with Tourette's said profanities to you during your Zoom meeting, would you hold them equally responsible as a person not having it? No, because it's a symptom and you assume it is out of their control and they didn't have a malicious intent. If both persons said "sorry it wasn't in my control", you'd think 1) the person A didn't do bad, because they have a tic and they defin…

> t is out of their control and they didn't have a malicious intent

We just established nobody chooses what they do or how they feel, so at best it's like a matter of degree and at worst it's completely arbitrary.

Re: Why Quantum Mechanics?

#110

Post by pontus »

lisper wrote: post #6
guerrilla wrote: post #5

I've always liked these kinds of questions. Myself, I always wondered why specifically three dimensions. (Please don't start telling me about string theory.)

I wondered that for a long time myself and recently stumbled on what I believe is (or at least is a good candidate for) the correct answer: planetary orbits are stable in three dimensions, but not any other dimensions. The anthropic principle therefore selects for three-dimensional slices/subsets of the wave function.

Anthropic arguments only work if there's a mechanism for generating other versions besides the one you're observing. For example, you could use the anthropic argument to explain why earth is in the "goldilocks zone" because there are plenty other planets out there at varying distances from their sun.

So, if you want to make the argument that 3d is preferred for some reason you need to acknowledge that there are other universes out there with 2d, 4d, etc that just can't sustain life and that therefore life only finds itself in the subset of universes that have three dimensions.

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