# Measurement problem

Discussion in 'Science and Nature' started by dce, Sep 21, 2009.

1. Measurement Problem
Does anyone have an opinion on the conscious observer's role in quantum theory?

I for one find it a little hard to believe that the tree over their doesn't exist unless I look at it.

2. It's not about observing as such. The problem is two-fold, interference and statistically significant numbers.

First, any direct measurements means interfering, which again collapse the probability wave into spatial particles. It is not as if observing at such small scales is non-intrusive.

Second, QM is just about probability. This is rather random at the individual particle level, but with a greater statistical foundation, it all evens out to a predictive mean value.

Like with any radioactiver material. If you just had one atom of the stuff, there is no way of telling when it will bounce down in energy levels and emit some radioactive (weak force) radiation. Given some more substansial amounts of the stuff though, and you can predict exactly the release and decline of radiation (ie halflife) from the mass as a whole.

So observer or not, the tree is still there.

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3. You've nailed it exactly...it's a measurement problem.

There are very small things that we can't measure (see), that have an effect on things that we CAN measure (see). So, sometimes, something "magically" (randomly) happens to something we can see by something we can't and we try to explain it with wacky theories full of holes and "inelegant" equasions.

Since we can't see whether or not the unseen thing is going to affect whatever we're looking at...we call it "random". If we could see these smaller things, we could predict it and it wouldn't be random any more.

Brownian motion of ink in a glass of water seems random only because we can't see the atoms zooming around hitting ink molecules. If we could, it would no longer be random. If we could see atoms moving in real time in a glass of water, we could predict future positions of ink molecules.

4. So what about schrodinger's cat? There's a chance the cat is both dead and alive it exists in one form or the other but from what if I understand correctly it's in fact both with the wave function not being colloapsed at a single point until observed. Is that right?

5. I think that's correct, dce.

6. That's nothing but probability...again, making up something as RANDOM because you don't know WHY it happens. I think there's a reason for randomness...it's just too small to measure.

It's bullshit science... Of course the cat is either alive or dead until you look. UNLESS you know something that other people don't. Unless you can SEE something that others can't. Maybe you can see that lethal particle enter the box...and nobody else can. And you DO know it's state before observing it.

Actually, I like the other one better...the act of observing changes what you're looking at.

7. You are so uninformed my friend.

8. yeah strange things can happen man, I was at a vending machine and it ate my dollar, well I put my hand on the glass and it went right through

9. Lol, yea man I know exactly what your talking about!

10. #10
Last edited by a moderator: Sep 22, 2009
Yup, that's a misinterpretation of the way quantum mechanics works.

Here's how it goes. The world we live in is considered to be local in nature. The long and short of it is that the only way to gain information about something is by interacting with it somehow. You can't just know what a particle's doing. You have to do something to it to find out. So in order for a physicist to, say, observe a particle, she needs to do something to it, such as, for example, firing a photon at it.

Well, that actually poses a little bit of a problem for quantum mechanics. The particle, prior to that photon being fired at it, was actually a quantum waveform. It was a probability of what it could be doing spread out over space. The photon forces the waveform to collapse into just one of those possibilities, only we'd really love to study waveforms on their own. So the very act of firing the photon at the waveform for the purposes of studying it in fact destroys the waveform.

Basically, the idea of "observation" in quantum contexts means a very specific kind of scientific observation that has nothing to do with what you do when you point your eyes at a tree. As Zylark said, it's all a lot of probabilities that on macro scales even out into a roughly-predictable system. It's nothing to do with that flimflam peddled by films such as What the Bleep do we Know?!

When a physicist sits down to talk about this, however, they're still stuck in their own little world and aren't thinking that a word like "observe" which so obviously has a certain meaning to them in the context of quantum mechanics might cause some confusion to the rest of the world who doesn't know what they mean.

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11. But see there is the problem the photon isn't some "magical" cue for the wave function to collapse, which is what I thought for a while. Which is why it carries such implications with consciousness (or what ever you want to call it) that every physicist since Einstein and Planck has thought considerably on. It's actually that weird but you know the majority of this is a bit difficult for me to understand and interpret so I could be preaching a lie.

12. I don't how conscious beings can activate particles by looking at them or interacting with them. Why can't they just exist unobserved?

I mean things still happen on their own and we won't know about them for years but feel their effects.

13. They can...but they might not be there too...you don't know until you look. And in the QM world...the act of looking changes things.

It's mumbo jumbo to try to explain that which happens at VERY small levels...sub atomic.

I personally explain it by other smaller things effecting them...sub(er) atomic particles having an effect on sub atomic particles. We can't see the sub(er) atomic particles so we can't predict when/how they will act. We see their influence but we can't see them themselves.

It's like leaving cheese in a dark room with mice. Sometimes when you turn the light on the cheese is still there. Sometimes it's not. Since you can't see the mice in the dark...it becomes "probability". QM works the same way. We can't see the "mice" so we make up these strange theories full of FM (fucking magic) that don't quite work. We'll need to be able to "see the mice" before we can solve it.

Simplified by close enough I think...

14. i feel smarter for reading this. lol. im stoned. my mind is thinking of questions my brain cant answer at the moment now. fuck lol got the ol gerbil wheel moving now.

15. #15
Last edited by a moderator: Sep 22, 2009
It is not merely looking. That implies photons just bouncing off an object and hitting your retina. Not how it works when trying to see the really small.

Well, that "mumbo-jumbo" as you call it works like a charm. It's never been proven wrong in the slightest, and more important, in practical terms it works as predicted. QM might give one headaches now and again, but as far as scientific theories goes, it is one of the more substanciated. For the simple reason that it's been tested so much due to scientists themselves not quite believeing the results from the QM field of research. So double, and triple checking have been done.

And now we're even starting to see practical applications of the theory coming online.

That is what string theory is about. Taming QM in order to unify it with general relativity. It works too, if only mathematically at the moment.

Cute analogy. Quite like it. But it isn't "Fucking Magic that don't quite work". It do work to perfection, and have very little to do with magic.

An even better, which takes into account more than one probability instance, is the popcorn analogy.

Say you got your pot all hot, butter simmering nicely. Then you pour in the corn. Now, you'll never know what single corn will pop first, or second or third and so on. But you do know, that on average, two minutes later near all, let's say 99%, of the corn are popped, and you got snacks to go with your beer, blunt and movie

So there is a certain determinance to the equation. From 0 to 2 minutes, there is a 99% chance that any given corn will pop. It is random within a given timeframe, but near certain outside of it.

16. Alright this is why, when simply observing an object it comes into existence. When observed, an atom has its an electrons oriented in a specific manner, so as a result it carries physical properties. Now quantum mechanics is probability functions but we know that when observed the electrons exist in a particular area. Because of differing dipole moments, one of an infinite number outcomes are possible, but cannot be known until observed. I stumbled on this idea below in class today and I think it describes, the measurement problem at least, in a nut shell:

Reality is Perception

17. It doesn't "work like a charm"...it works "good enough" for what we need from it. It's like comparing Newton to Einstein...here on earth...going from point A to B, Newtonian physics "works like a charm". But when you get bigger...it doesn't hold up well enough. QM is the same. There are all kinds of theories about how things happen and why. Nobody knows.

Your popcorn and my cheese are actually the same...eventually the mice WILL find the cheese and it will disappear. IF you could study each kernel carefully enough with enough detail, I believe you COULD determine the order of the popping. We just don't know all the facts yet. And I believe that some things that affect "us" are too small to EVER know about with any degree of certainty.

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