Free will?

[YesNo]

I'm glad you liked it, cafolini, with or without the vodka.

I was trying to figure out just what the Copenhagen interpretation is, when I read this in Wikipedia (http://en.wikipedia.org/wiki/Copenhagen_interpretation) which seemed to compare the two interpretations nicely.

So if an electron passes through a double slit apparatus there are various probabilities for where on the detection screen that individual electron will hit. But once it has hit, there is no longer any probability whatsoever that it will hit somewhere else. Many-worlds interpretations say that an electron hits wherever there is a possibility that it might hit, and that each of these hits occurs in a separate universe.

So, if I'm getting this right, when an electron hits the detection screen in the Copenhagen interpretation it just hits the detection screen at a particular location and its chance of hitting the detection screen at some other point drops to zero. That's what "wave function collapse" means.

In the Many Worlds interpretation, since hitting the detection screen involves non-determinism at the level of an electron, it has to come up with as many alternate universes as there are places where that electron could hit. That's what "non-collapse" of the wave function means.

I can't think of anything more damaging to an interpretation than to have to posit the creation of perhaps trillions of new universes every time a scientist shoots an electron through a double slit experiment.

[YesNo]

The Copenhagen interpretation assumes that the wave function collapses, because Bohr wanted free will. Everett didn't present the Many Worlds Interpretation because he wanted determinism; it was because there is npthing in the math that requires that the wave function collapse. If one examines both, then one will find equally valis math, and both agree with observable reality, unless you demand that yous see all possible worlds at all times.

What requires the wave function to collapse is the electron hits the detection screen or some other change occurs implying that something definite actually happened. The wave function presenting the probabilities where the electron will hit is no longer needed because we now know where it landed and we have a 100% probability of the result.

You are making an assumption that both interpretations use equally valid math. I don't know if that is the case or not. I can see how one might be able to split the wave function into pieces, provided there is a suitable basis which better be uniquely determined, one for each hypothetical alternate universe because of the linearity of the function, but I don't see how the math can put them back together again to generate what Many Worlds must interpret as an illusion of a wave pattern on the detection screen.

What part of the math generates the ultimate wave pattern after many of these single-fired electrons hit the detection screen? The problem here is that if each of the alternate universes knows where its electron will hit, it has already "collapsed the wave function" for its electron. All one will get is the expected random pattern on the detection screen, not that unexpected wave pattern. Many Worlds has to explain the wave pattern without hand-waving, without taking polls of who is currently supporting it, without pseudo-scientific magic, and do all this with its spooky alternate universes.

It is sort of like what happens when the kid asks the parent, "Well, how does Santa actually get down the chimney?" And his parents make up some BS they hope the kid will swallow.

This is not a good analogy. The Copenhagen Interpretation would say that Daddy put the presents there. The Many Worlds Interpretation would say that the presents are there, and there are many people who might have put them there: Mommy, Daddy, Aunt Sue, etc. and we don't know who is guilty, because they were all there and had presents.

If MW is the Santa Claus interpretation, then DI is the warm bed with teddy bear solution.

A better analogy would be to use Young Earth Creationism, but I didn't find it as amusing at the time: http://en.wikipedia.org/wiki/Young_Earth_creationism

[PeterL]

What requires the wave function to collapse is the electron hits the detection screen or some other change occurs implying that something definite actually happened. The wave function presenting the probabilities where the electron will hit is no longer needed because we now know where it landed and we have a 100% probability of the result.

While the electron is detected in a certain place, that does not mean that the other probabilities disappear. it simply means that they were not detected. That’s all.

You are making an assumption that both interpretations use equally valid math. I don't know if that is the case or not. I can see how one might be able to split the wave function into pieces, provided there is a suitable basis which better be uniquely determined, one for each hypothetical alternate universe because of the linearity of the function, but I don't see how the math can put them back together again to generate what Many Worlds must interpret as an illusion of a wave pattern on the detection screen.

I am not assuming that they use the same math. I know that they are using the same math. The difference is in how they interpret the fact that electrons can be observed in one place.

What part of the math generates the ultimate wave pattern after many of these single-fired electrons hit the detection screen? The problem here is that if each of the alternate universes knows where its electron will hit, it has already "collapsed the wave function" for its electron. All one will get is the expected random pattern on the detection screen, not that unexpected wave pattern. Many Worlds has to explain the wave pattern without hand-waving, without taking polls of who is currently supporting it, without pseudo-scientific magic, and do all this with its spooky alternate universes.

That an electron has been detected in a given place makes no difference to the math.

It is sort of like what happens when the kid asks the parent, "Well, how does Santa actually get down the chimney?" And his parents make up some BS they hope the kid will swallow.

A better analogy would be to use Young Earth Creationism, but I didn't find it as amusing at the time: http://en.wikipedia.org/wiki/Young_Earth_creationism

Yes, there is a religious quality to the Copenhagen versus Many Worlds interpretations of QM.

If you want to look strictly at the math, then MW is better, because it does not claim that anything happens that is not clear in the math. If you look at "real world" results, then Copenhagen in is better, because it agrees with what we see, maybe.

[cafolini]

I'm glad you liked it, cafolini, with or without the vodka.

I was trying to figure out just what the Copenhagen interpretation is, when I read this in Wikipedia (http://en.wikipedia.org/wiki/Copenhagen_interpretation) which seemed to compare the two interpretations nicely.

So if an electron passes through a double slit apparatus there are various probabilities for where on the detection screen that individual electron will hit. But once it has hit, there is no longer any probability whatsoever that it will hit somewhere else. Many-worlds interpretations say that an electron hits wherever there is a possibility that it might hit, and that each of these hits occurs in a separate universe.

So, if I'm getting this right, when an electron hits the detection screen in the Copenhagen interpretation it just hits the detection screen at a particular location and its chance of hitting the detection screen at some other point drops to zero. That's what "wave function collapse" means.

In the Many Worlds interpretation, since hitting the detection screen involves non-determinism at the level of an electron, it has to come up with as many alternate universes as there are places where that electron could hit. That's what "non-collapse" of the wave function means.

I can't think of anything more damaging to an interpretation than to have to posit the creation of perhaps trillions of new universes every time a scientist shoots an electron through a double slit experiment.

I tend to agree, in fact. Good points.

[Cioran]

If you want to look strictly at the math, then MW is better, because it does not claim that anything happens that is not clear in the math. If you look at "real world" results, then Copenhagen in is better, because it agrees with what we see, maybe.

Yes! Exactly!

I haven't been able to bestir myself to read the latest from YesNo, and don't know if I care to aggravate myself to do so, but here you have hit the nail on the head. If YesNo is suggesting that the math supports Copenhagen and does not support MW, he is, as he usually is, dead wrong. MW and Copenhagen both are perfectly consistent with the observed results and predictions of QM. However! Nothing in the math predicts or models a wave function collapse, which is what Copenhagen needs to defeat Many Worlds. Thus YesNo has got it exactly backward (what a suprise!) again. MW is just all math! It's Copenhagen that puts in a totally unexplained wave function collapse, which not only fails to be supported by the math, but physically speaking, has no explanation whatsoever. It's pure magic!


Copenhagen is Santa Claus, of course!

[PeterL]

Yes! Exactly!

I haven't been able to bestir myself to read the latest from YesNo, and don't know if I care to aggravate myself to do so, but here you have hit the nail on the head. If YesNo is suggesting that the math supports Copenhagen and does not support MW, he is, as he usually is, dead wrong. MW and Copenhagen both are perfectly consistent with the observed results and predictions of QM. However! Nothing in the math predicts or models a wave function collapse, which is what Copenhagen needs to defeat Many Worlds. Thus YesNo has got it exactly backward (what a suprise!) again. MW is just all math! It's Copenhagen that puts in a totally unexplained wave function collapse, which not only fails to be supported by the math, but physically speaking, has no explanation whatsoever. It's pure magic!

Yes, Bohr wanted to make QM matcvh the observed world, but there was no need for that. There is nor reason for the wave function to collapse to explain what is observed. Just because the electron is observed in one place says nothing about its wave-like nature.

[Cioran]

Here, read this.

The Copenhagen interpretation requires that new laws be created that, in addition to being impossible, are completely unnecessary, physically unfeasible, and utterly unjustifiable. The basic laws of quantum mechanics, when applied at all scales, give you the Many Worlds interpretation. No fancy rules, no awkward questions. Even better, what seems to be wave function collapse in Copenhagen is actually described by the Many Worlds approach. So why choose the Copenhagen interpretation over Many Worlds? No damn reason at all.

See? It’s Copenhagen that requires you put in extra stuff apart from the math, not MW! And it’s Copenhagen that postulates a totally magical, wholly unexplained, Santa Claus-like wave function collapse! It’s Copenhagen that makes the audacious, wholly unexplained and unexplainable assertion that human consciousness transforms the whole universe every time someone measures something!

YesNo seems to be arguing that MW must be wrong because he wants it to be wrong. Apart from this sort of behavior being really annoying, one must ask why it's important to him that MW be false? I think it's because he believes that free will is vindicated if the universe is indeterministic, as implied by Copenhagen.

But it's not! I guess YesNo has failed to notice that a universe based on hard indeterminism is exactly as fatal for free will as one based on hard determinism!

[cafolini]

Here, read this.



See? It’s Copenhagen that requires you put in extra stuff apart from the math, not MW! And it’s Copenhagen that postulates a totally magical, wholly unexplained, Santa Claus-like wave function collapse! It’s Copenhagen that makes the audacious, wholly unexplained and unexplainable assertion that human consciousness transforms the whole universe every time someone measures something!

YesNo seems to be arguing that MW must be wrong because he wants it to be wrong. Apart from this sort of behavior being really annoying, one must ask why it's important to him that MW be false? I think it's because he believes that free will is vindicated if the universe is indeterministic, as implied by Copenhagen.

But it's not! I guess YesNo has failed to notice that a universe based on hard indeterminism is exactly as fatal for free will as one based on hard determinism!

It comes to a point where anything goes with Smirnoff. LOL

[cafolini]

Yes, Bohr wanted to make QM matcvh the observed world, but there was no need for that. There is nor reason for the wave function to collapse to explain what is observed. Just because the electron is observed in one place says nothing about its wave-like nature.

The electron does not have a wavelike nature. Waves are a mathematical notation of pulses that has nothing to do with the intrinsic nature of the electron. Don't be ridiculous. Just drink your pood and relax. Bohr was correct and that's why he could not take the retarded position of Einsteinsaurus. Only one world out there and a few exceptionally retarded interpretations wanting to take physics as the language for math. QM is as solid as the principle of uncertainty which simply states that you cannot fotograph the electron and know its actual location at the same time. No more. Watch your breathing.

[Cioran]

It comes to a point where anything goes with Smirnoff. LOL

That's right, parade your shallow understanding of the topic with snarky one-liners while the rest of us try to educate you. Futilely, no doubt.

[Cioran]

The electron does not have a wavelike nature.

Demonstrably incorrect, and evidence of your shallow grasp of this topic. Everything has a wavelike nature, including you. This has been empirically demonstraed. I don't know if you even know what the two-slit experiment is, but in it, objects as large as Buckyballs have been "waved" through the two slits. So sorry for your claim.

[Cioran]

For any lurkers or participants who would like to know more about this fascinating topic, here is transcript a show that NOVA did a few years ago on the Many Worlds, very friendly to the lay reader.

[cafolini]

Demonstrably incorrect, and evidence of your shallow grasp of this topic. Everything has a wavelike nature, including you. This has been empirically demonstraed. I don't know if you even know what the two-slit experiment is, but in it, objects as large as Buckyballs have been "waved" through the two slits. So sorry for your claim.

When you quote me, please show the entire quote. I know it must be difficult with so much vodka.

[cafolini]

The electron does not have a wavelike nature. Waves are a mathematical notation of pulses that has nothing to do with the intrinsic nature of the electron. Don't be ridiculous. Just drink your pood and relax. Bohr was correct and that's why he could not take the retarded position of Einsteinsaurus. Only one world out there and a few exceptionally retarded interpretations wanting to take physics as the language for math. QM is as solid as the principle of uncertainty which simply states that you cannot fotograph the electron and know its actual location at the same time. No more. Watch your breathing.

[Cioran]

When you quote me, please show the entire quote. I know it must be difficult with so much vodka.

Do the rules here allow this sort of posting?