[Halc]

It didn’t to Schrödinger who intended it as an example of the absurdity of such an interpretation. The problem is that many people have misunderstood what he was trying to say.

But it only seemed absurd back then in the early days of QM when they were still hoping for a classic interpretation of things. In principle, there's nothing contradictory about the cat being in such a superposition. In practice, there's no conceivable way to put it in a box and actually not measure it, except if the box was so large that it took significant time for the measurement to be taken. The have done this to macroscopic objects (large enough to see unaided), but the conditions utilized to 'put it in a box' would have killed any cat.

Because our actual actions of seeking definition render either answer if I am right in my understanding of it. It can be both alive and dead, 0 and 1.

This seems to be a classic assumption, and while intuitive, it's wrong. It is in superposition of 0 and 1 until measured, at which point it collapses to one state or the other, as described by an interpretation with collapse. Other interpretations deny collapse, in which case the observer simply becomes entangled with the cat.

[geordief]

This seems to be a classic assumption, and while intuitive, it's wrong. It is in superposition of 0 and 1 until measured, at which point it collapses to one state or the other, as described by an interpretation with collapse. Other interpretations deny collapse, in which case the observer simply becomes entangled with the cat.

OK so this presumably applies to any quantum object,?

For the purposes of us making any determination about it we have to take every probability  regarding its properties and take those probabilities(why are there more than one I don't know) and fix them to actually represent the object.

When that object interacts with its environment  the probabilities are rearranged instantly (?) and there is s new object based on a new set (again why so many superpositioned  probabilities?) of probabilities

Is that anywhere close?

[Halc]

OK so this presumably applies to any quantum object,?

All objects are quantum objects. It's just really hard not to interact with any nearby thing with any significant size.

For the purposes of us making any determination about it we have to take every probability regarding its properties and take those probabilities(why are there more than one I don't know) and fix them to actually represent the object.

If I read that correctly, it sounds like every object has a wave function via which one can in principle compute probabilities of measurements not yet taken. If that's what you mean, I agree.

When that object interacts with its environment  the probabilities are rearranged instantly (?) and there is s new object based on a new set (again why so many superpositioned  probabilities?) of probabilities

That sounds like collapse. Yes, that's a way of describing collapse, for an interpretation that supports collapse.

Is that anywhere close?

I didn't disagree with any of it.

[alancalverd]

It is in superposition of 0 and 1 until measured, at which point it collapses to one state or the other,

Which clearly cannot be true as no molecule inside the cat knows that it is not being observed.

Usual problem of confusing a mathematical model with reality. The model gives us an idea of what we are most likely to observe - it is a probability function - but doesn't explain the mechanism.

An accurate model of roulette, superposing your chosen number and the 37 other numbers and predicting the outcome of the probability function collapse,  tells you that you will almost certainly lose, but the ball and the wheel are visibly solid throughout the losing process (one could hardly call it a "game"). It's more interesting than Schrodinger's cat because there are three outcomes: you win everyone else's money (very unlikely) , somebody else wins yours (very likely), the house wins everyone's (twice as likely as you winning).

Hence many predictive "Monte Carlo" algorithms, leading to controlled nuclear fission and a whole bunch of other stuff.

[Colin2B]

It didn’t to Schrödinger who intended it as an example of the absurdity of such an interpretation. The problem is that many people have misunderstood what he was trying to say.

But it only seemed absurd back then in the early days of QM when they were still hoping for a classic interpretation of things. In principle, there's nothing contradictory about the cat being in such a superposition.

I agree. I have no problem with the cat being described as in a superposition of states, just with the cat being dead and alive at the same time

For the purposes of us making any determination about it we have to take every probability  regarding its properties and take those probabilities(why are there more than one I don't know) and fix them to actually represent the object.

It’s the nature of probabilities, by which I’m assuming you mean the probability of various outcomes. For a coin toss there are 2 outcomes, for the top card of a deck 52, so we can calculate the probability of these outcomes. The probability given by the wave equation of say the hydrogen atom gives us the probability of finding the electron at different positions around the nucleus - Alan’s fuzzy electron cloud. This is quite similar to the example of a friend driving to your home, where we can create a probability distribution of the probability of finding your friend at a certain distance from your home.
As Alan says we can use probabilities to model many practical situations including supermarket checkout queues, telling us how many staff and checkouts are needed.

When that object interacts with its environment  the probabilities are rearranged instantly (?) and there is s new object based on a new set (again why so many superpositioned  probabilities?) of probabilities

Let’s take a practical example of an electron inside a tunnel diode. We have a wave function describing the electron from which we derive the probabilities that the electron will be at certain distances from the barrier. Inside, highest probability, outside lowest - you should be able to find the actual distribution online. If the electron crosses the barrier its probability of being outside is 1 and the probability of it being inside is 0, we say the wave function has collapsed to a definite value. The electron is not a new object, but we do need a new wave function to describe the probability that it will cross back over the barrier or travel on its way through the copper lattice. How you describe this process depends, you could say wave function collapse + new wave function or wave function update. A lot of us are really considering updates as a good way of describing what happens and you can see this is the state changes eg in the hydrogen atom, when the atom absorbs a photon and the wave function of the electron changes giving a different probability distribution for position.

[yor_on]

The measurement problem in quantum physics is a can of snakes.

https://physics.mq.edu.au/~jcresser/Phys301/Chapters/Chapter13.pdf

and https://plato.stanford.edu/entries/qt-issues/



spelling, again

[yor_on]

There are three different parameters here. One is the measurement, another is the observer (observer effect) and the third is HUP.
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Take two atoms 'colliding/bumping' without any measurement. Would that be different from us making them bump while probing? You can't do this one, the first is more or less impossible to test, other than very indirectly. You can use statistics for it, experiences of how it usually falls out of course but for a singular case?

It depends on how strict you want to be possibly? But HUP do set a, so far indisputable, limit to what is knowable.

[yor_on]

https://www.thoughtco.com/what-is-schrodingers-cat-2699362    is about the observer effect.  At least if viewed from the Copenhagen interpretation.

" Still, in some strict views of the Copenhagen interpretation, it is actually an observation by a conscious entity which is required. This strict form of the interpretation is generally the minority view among physicists today, although there remains some intriguing argument that the collapse of the quantum wavefunctions may be linked to consciousness "
=

And that one leads me to Bells theorem

http://scholarpedia.org/article/Bell%27s_theorem

which leads me to decoherence as an explanation. Your reason for existing, decoherence. And here's one try to explain it :)

https://www.theatlantic.com/science/archive/2018/10/beyond-weird-decoherence-quantum-weirdness-schrodingers-cat/573448/

which all is good and clean, Understandable in some wavy way. But then we have HUP :)

Don't read me wrong here. I totally agree with this.

" We don’t need a conscious mind to “look” in order to “collapse the wave function.” All we need is for the environment to disperse the quantum coherence. We obtain classical uniqueness from quantum multiplicity when decoherence has taken its toll. "

It's what I say too. It must be that way. Eh, the first part I mean " We don’t need a conscious mind to “look” in order to “collapse the wave function.”  Whether the rest of it is the most correct explanation I don't know.
==

You could look at it this way. Assume that the 'strict' Copenhagen interpretation is correct. You need to look before the moon will exist. What that state though is that the moon must 'know' where to 'exist' each time you search for it. It would either make you the whole universe, or make that moon 'sentient' in some mean.

[geordief]

You could look at it this way. Assume that the 'strict' Copenhagen interpretation is correct. You need to look before the moon will exist. What that state though is that the moon must 'know' where to 'exist' each time you search for it. It would either make you the whole universe, or make that moon 'sentient' in some mean

That would mean the whole universe's existence  depended on a particular sentient observer's perception. (solipsism?)

That is a reductio  ad absurdissimum.

It is the other way round,of course.

[Halc]

You could look at it this way. Assume that the 'strict' Copenhagen interpretation is correct. You need to look before the moon will exist. What that state though is that the moon must 'know' where to 'exist' each time you search for it. It would either make you the whole universe, or make that moon 'sentient' in some mean

You seem to describe the Wigner interpretation. Copenhagen (as a metaphysical interpretation) does not put any special significance on humans or consciousness.

That would mean the whole universe's existence  depended on a particular sentient observer's perception. (solipsism?)

Indeed, even Wigner himself abandoned the interpretation bearing his name because of exactly this reason.

[Harri (OP)]

I'd just like to say thanks to everyone who's taken the time to contribute to this post. It's given me a really interesting insight into the subject.

[yor_on]

Ahh geordief, but it do open for some very interesting philosophy

Just imagine. Where ever you are you will be the center of the universe, and so will I.
It holds astronomically too :)

No matter where you go you will see the same universe around you, as defined large scale. and the same physics, laws and properties. Those are fundamentals for most mainstream physics today that I've seen.
=

actually, and this is even more peculiar, it also holds for the definition of locality in relativity. At least the way I interpret it, because everything is 'observer dependent' there making you, and your definition of the universe, distances and time, a complementary unique experience. and if that doesn't blow your mind you're tougher than me.

[yor_on]

Halc, you might find this interesting :) in a somewhat rambling way.

https://phys.libretexts.org/Bookshelves/Quantum_Mechanics/Quantum_Mechanics_(Walet)/13%3A_Miscellaneous_Quantum_Mechanics_Topics/13.03%3A_Complementarity_and_Copenhagen_Interpretation

[Colin2B]

Halc, you might find this interesting in a somewhat rambling way.

I don’t think this is telling @Halc anything he doesn’t know.
However, it does remind me that I owe you a reply. Been busy.

[yor_on]

It all depends on how you read it Collin. What Bohr called 'complementary'. The most easily accepted version is the one in where every interaction can be seen as a 'observation', the process 'observing itself'. But as far as I remember the other school exist too, the one that connects it to consciousness. As mentioned in https://www.thoughtco.com/what-is-schrodingers-cat-2699362

I normally prefer the one where every 'interaction observe itself', but I'm not totally sure of it.

This one argues for it.  https://www3.nd.edu/~dhoward1/Copenhagen%20Myth%20A.pdf
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I don't know? You might be able to connect it to decoherence stating that it is a question of the scale of what you observe, or of it 'interacting'', thinking of 'inanimate objects' interacting (not needing any 'conscious observation')

thinking some more of it. Assume you're at some relative motion, as defined from your origin. According to relativity your distance in the direction of motion shrinks. You have presumably 'zero point energy' existing intrinsic to the vacuum consisting of that shrunk distance, or we may call it 'waves'. You now go out to measure the energy density of the vacuum in front of you. Would you expect it to differ from some other observer doing the same while not at your relative motion? Does it matter what relative motion you define to yourself?  It's just a thought experiment, although you might be able to use the Casimir effect to measure it by?  https://en.wikipedia.org/wiki/Casimir_effect