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Posted

That's not exactly certain.

 

Quantum theory, according to that article and other books I have read, essentially says "it doesn't have a definite position unless someone looks." If there's a particle in a closed box, not only do we not know where it is in the box, it doesn't either, until we open it up and look. The question is "what defines 'observer'?"

 

Look, I read the books, I'm the expert here :P This is really a separate topic, anyway.

Posted
Why are ethics and philosophy not open to scientific explanation?

In the limit they both happen in human brains; they are the results of a very complicated set of chemical reactions.

 

But once they are the results of the chemical reactions, you have to decide whether those results are accurate. That decision about accuracy is independent of the chemical reactions. IOW, whether murder is ethical is independent of the chemical reactions. It is either ethical or not.

 

So, how do you scientifically decide what is ethical? You don't. Science is not a system of ethics. There is ethical behavior associated with science; behavior that someone doing science should or should not do.

 

The classic case showing the difference between what we know by science and ethics is the atomic bomb. Science tells us what happens when an uranium or plutonium atom fissions. But nothing in the explanation of fission tells us that we should (ethics) build a bomb and explode it on Hiroshima.

 

As far as I know religion doesn't really answer anything anyway- saying "because God said so" isn't an answer unless you explain God.
How God asks people to behave is part of an explanation of God. Just like parents teaching their children how to behave is part of an explanation of "parent". We explain entities mostly by listing what the entity does.

 

For instance, originally atoms were explained as entities that "said" how gasses behave. :)

 

Religion can be viewed as a hypothesis to explain personal experiences that people have. For instance, Yahweh is a hypothesis to explain the experiences of Moses and the Hebrews in the Exodus. Allah is an explanation for the experiences Mohammed had -- where Mohammed claims an entity told him the things that eventually Mohammed wrote down in the Quran. Millions (at least) of people have had personal experiences that, by testing to eliminate other possibilities, they have settled on the hypothesis "God" to explain them.

 

Ethics, morality, etc. are products of human interaction as social beings...products of evolution of life forms. They don't arise out of 'nothingness' but natural selection.

 

That's not what evolutionary psychologists are saying. I was just reading an interview with Mark Hauser in Discover.

 

What evolutionary psychologists are saying the moral decisions are hardwired by natural selection. That is, we decide to do the moral action. But they avoid saying that what constitutes a moral action is a product of evolution. IOW, what is "moral" is separate from evolution and natural selection. Natural selection just causes us to do, at a genetic level, what is moral .

 

Because you can't make predictions about ethics and philosophy.

 

You are using "prediction" in the common usage, not the scientific one. In common usage, "prediction" is "predicting what will happen in the future". In science "predict" means "predict knowledge you should find if the hypothesis is true". Both ethics and philosophy do this to an extent.

 

Quantum theory, according to that article and other books I have read, essentially says "it doesn't have a definite position unless someone looks." If there's a particle in a closed box, not only do we not know where it is in the box, it doesn't either, until we open it up and look. The question is "what defines 'observer'?"

 

That is what the books said. However, recent data shows the books to be wrong. Sorry, science marches on. It turns out that there is a period of time where Schrodinger's cat is both dead and alive at the same time, but without anyone looking that period ends and only one reality exists. If you want, I can provide references so you can get caught up.

 

BTW, Paul Davies and others did propose deity as the "observer" that continually defined reality.

Posted
That is what the books said. However, recent data shows the books to be wrong. Sorry, science marches on. It turns out that there is a period of time where Schrodinger's cat is both dead and alive at the same time, but without anyone looking that period ends and only one reality exists. If you want, I can provide references so you can get caught up.

 

Please do. Although the New Scientist article I referenced was recent (the latest issue), I'd like to read whatever else there is available on the topic.

Posted
Please do. Although the New Scientist article I referenced was recent (the latest issue), I'd like to read whatever else there is available on the topic.

 

Can you post the New Scientist article? It was last week and I can only see the introduction. It doesn't address what you talk about but the title hints at it. It sounds like we may have 2 different sources of information and they contradict. Or they may be talking about similar sounding, but different, things. You did mention not knowing the position until we look, while the other posts were talking about Schroedinger's Cat. We need to check.

 

My references about decoherence and coherence are:

5. G Taubes, Atomic mouse probes the lifetime of a quantum cat. Science, 274 (6 Dec): 1615, 1996.

6. P Yam, Bringing Schrodinger's cat to life. Scientific American, June, 1997, pp. 124-129. Summary of recent experiments of superposition (coherence) and dechoherence.

7. GP Collins, Schrodinger's SQUID. Scientific American 283: 23-24, October 2000. Electric current flows both ways around a superconducting loop at the same time.

Posted
The world' date=' Aspect announced, could not be both local and real - Einstein was wrong. But which idea had to go, realism or locality? Do particles only acquire real properties when they are measured? Or are distant, instant influences possible between particles?

 

The answer would come from another source. In 1976, well before Aspect had carried out his experiment, physicist Anthony Leggett had what he calls "the kernel" of an idea to rework Bell's formula with a twist: he quantified what you would get if you made measurements on entangled particles, assuming that distant, instant influences were in fact possible. Leggett eventually published this formula in 2003, the year he won the Nobel prize in physics for his work on the quantum properties of helium-3.

 

Enter a team of Austrian and Polish physicists, who have now done experiments on pairs of entangled photons to test Leggett's formula (see "The end of reality"). The team, led by Markus Aspelmeyer of the Austrian Academy of Sciences and Anton Zeilinger of the University of Vienna, managed to reduce the noise in their set-up by a necessary factor of 10, compared with Aspect's work. They published their results in April (Nature, vol 446, p 871).

 

What they found is that Leggett's formula is violated as well: even if you allow for instantaneous influences, quantum measurements do not fit with the idea of an objective reality. This is surprising because you might expect that, once any spooky "non-local" action is allowed, you could account for almost any relationship between two particles, and there would be no reason to ditch our concepts of reality. "This is not the case," says Aspelmeyer.

 

Although some loopholes remain - not all non-local models have been ruled out - we now have to face the possibility that there is nothing inherently real about the properties of an object that we measure. In other words, measuring those properties is what brings them into existence. "Rather than passively observing it, we in fact create reality," says quantum researcher Vlatko Vedral of the University of Leeds, UK.[/quote']

 

That's just an excerpt... don't want copyright trouble. But I can post more if you'd like. It's a long article.

Posted
That's just an excerpt... don't want copyright trouble. But I can post more if you'd like. It's a long article.

 

Yes, we are talking about 2 different things: coherence and entanglement. In coherence we have 2 quantum "realities" at the same time. In entanglement, you entangle 2 quantum particles. For an electron, you entangle the pair so that one is spin up and the other spin down. But you don't know which is which. You separate them, still without measuring them. Then you measure one of them. INSTANTLY the other one assumes the other value. That is, if you measure one as spin up, the other instantly becomes spin down. No matter the distance between them. Since in Relativity information can only go at lightspeed, this violates Relativity.

 

From Aspect's Commentary on Aspelmeyer's data:

"In contrast to wave–particle duality, which is a one-particle quantum feature, entanglement involves at least two particles. In entangled states such as those discovered by Einstein, Podolsky and Rosen (EPR)3, quantum mechanics predicts strong correlations between measurements on two systems that have previously interacted but which are separated at the time of the measurement (Box 1). To interpret these correlations, Einstein said, one must accept the concept of local realism. This principle states that results of measurements on a system localized in space-time are fully determined by properties carried along by that system (its physical reality) and cannot be instantaneously influenced by a distant event (locality)."

 

"It is then natural to raise the question of whether one should drop locality — which equates to the impossibility of any influence travelling faster than light — or rather drop the notion of physical reality."

 

I don't see this dichotomy. Instead, let's drop the idea of the impossibility of any influence travelling faster than light! No need to drop the notion of physical reality. We've already dropped the "fully determined" that Einstein used without dropping physical reality.

 

Now, Leggett has proposed ONE possible set of equations to have non-localit and realism. Aspelmeyer tested Leggett's equations and found they didn't work. BUT, as the Commentary says:

 

"Following Leggett, they conclude by questioning realism rather than locality — at variance with the often-heard statement that "quantum mechanics is non-local".

 

Interesting as this conclusion is, it remains a matter of personal preference, not of logical deduction. The violation of Bell's inequalities implied that realism and locality are not simultaneously tenable. Violation of Leggett's inequalities implies only that realism and a certain type of non-locality are incompatible: there are other types of non-local models that are not addressed by either Leggett's inequalities or the experiment."

 

It appears that the New Scientist article overstated the situation, stating the "personal preference" as the ONLY possible conclusion. I can see how you drew your conclusion; the fault is with the New Scientist article.

Posted

Please be patient with the following idiot rambling, but:

 

Being by nature an untutored sceptic I have been following this thread with quiet interest. But is it suggested that a local event creates its own reality (which seems reasonable)? And the properties of that reality could include its own local time, and time is not constrained by light-speed. Thus two independant local realities having the same properties, however distantly seperated, could share the same time and thus be connected in that way.

 

Two unrelated local events, having different time reality, when interacting, would thus alter each others reality.

Posted
Please be patient with the following idiot rambling, but:

 

Being by nature an untutored sceptic I have been following this thread with quiet interest. But is it suggested that a local event creates its own reality (which seems reasonable)? And the properties of that reality could include its own local time, and time is not constrained by light-speed. Thus two independant local realities having the same properties, however distantly seperated, could share the same time and thus be connected in that way.

 

That's not what is being said. We've evidently confused you. So, let me see if I can straighten out the confusion. Keep asking until you understand.

 

In Einstein's Relativity, lightspeed is the fastest anything can go. Therefore, all information is limited to lightspeed. If there is a flare on the sun, we won't know about it for 8 minutes since it takes 8 minutes for the photons to get from the sun to us. It is 8 minutes before the effects of the solar flare happen on earth. You simply can't "know" about anything the instant it happens, because the information can't travel faster than light.

 

Now along comes quantum mechanics. You can take 2 photons and polarize them "left" and "right" (L and R for short). But the polarization of the two of them can be entangled such that you don't know which photon is L and which is R. Now separate the photons still without knowing which is which. Send them down different optical wires. Then measure the polarization of one of them. INSTANTLY, at the same time, the other photon, wherever it is, will be the other polarization!

 

Do you see the problem? This has nothing to do with "local time", but rather that the information on the polarization of the photon (say it is L) is "sent" to the other photon faster than a photon could travel the distance.

 

Now, this applies ONLY to quantum particles that are "entangled". This means that they ARE "related" to each other. They have the same time reality. It's just that measuring one photon for the entangled property immediately "tells" the other photon to be the other property.

 

So... you could have an entangled photon in front of you and poof! without you doing anything, the photon is suddenly L. The "reality" of the polarization is determined by an event perhaps millions of light years away, yet it doesn't take millions of years for the information on what the photon "ought" to be to reach it.

 

Did this help?

Posted
It appears that the New Scientist article overstated the situation, stating the "personal preference" as the ONLY possible conclusion. I can see how you drew your conclusion; the fault is with the New Scientist article.

I see. But you have to admit, the concept that there is no objective reality at all is rather fun to think about.

 

Thanks for the explanation.

Posted
I see. But you have to admit, the concept that there is no objective reality at all is rather fun to think about.

 

Thanks for the explanation.

 

You are welcome. Yes, the concept is fun to play with. Based on the info in the article, I'm not willing to give up on objective reality just yet. IMO, the entanglement is part of objective reality: the particle is entangled or it is not. The particle was always R or L. That the particle stops being entangled and "becomes" either R or L upon observation does not mean, IMO, that we determine reality. We just "determined" which half of the entangled pair the photon was.

 

It's not like the photon was turned into a rabbit!

Posted

Lucaspa:

 

 

Yes, thanks for explanation.

Does it help? That depends:

Now along comes quantum mechanics. You can take 2 photons and polarize them "left" and "right" (L and R for short). But the polarization of the two of them can be entangled such that you don't know which photon is L and which is R. Now separate the photons still without knowing which is which. Send them down different optical wires. Then measure the polarization of one of them. INSTANTLY, at the same time, the other photon, wherever it is, will be the other polarization!

 

If I take two identical hemispheres arbitrarily labelled L and R such that they fit together seamlessly then toss them to the four winds, search for and find one, examine it and determine by ispection that it is L, I automatically and instantaneously know the other is R. This is deduced by elimination. If it really is that simple, I have again missed something. Sorry!

Posted

This concept is actually slightly controversial. People always use the "information traveled faster than the speed of light" explanation because that's what you read in popular science books; it's more interesting that way. I'm not here to tell you which method is correct, just that both yours and Lucaspa's explanations are acceptable. In a sense the two explanations are like two sides of the same coin.

 

Btw I think one of the guys in green have a phd in physics (swansont?) so maybe he knows.

Posted
Lucaspa:

 

If I take two identical hemispheres arbitrarily labelled L and R such that they fit together seamlessly then toss them to the four winds, search for and find one, examine it and determine by ispection that it is L, I automatically and instantaneously know the other is R. This is deduced by elimination. If it really is that simple, I have again missed something. Sorry!

 

It's not quite like this. You have 2 halves of the same whole thing. What we have instead is 2 different things that can each be 2 different ways.

 

Each photon can be either L or R. That is photon 1 can be L or R and so can photon 2. Your analogy has an "arbitrary" property L or R, but polarization isn't "arbitrary", it's a real physical property.

 

A better analogy would be 2 cups of water. Each could be either hot or cold. You have entangled them so that they are both "lukewarm". Separate them by a room. Put your finger in one and it is hot. The other one instantly becomes cold. It's not that you know it has to be cold due to elimination. Instead, the water actually turns cold. How did it know to do that? Why didn't it become hot? Or even stay lukewarm?

 

Is that better? Keep asking if you need to. The end point here is understanding. If you don't understand, you need to keep asking until you do.

Posted

Again that's just the "popular," "interesting" physics approach, there's a little more to it than just that. I had my physics book opened but I'm leaving for the beach and can't find the paragraph I'm looking for so have fun with all that.

 

It's kind of comparable to the concept of antimatter moving backwards in time instead of forward. You can represent antimatter mathematically in the sense of regular matter moving backwards in time but it's sort of controversial (for lack of a better term, two-sided coin again) as to whether or not antimatter actually does move backwards in time. The popular physics books always tell you that they DO go back in time, but this is only part of the story. If you've ever taken a physics class you'd know what I mean.

Posted
Again that's just the "popular," "interesting" physics approach, there's a little more to it than just that. I had my physics book opened but I'm leaving for the beach and can't find the paragraph I'm looking for so have fun with all that... If you've ever taken a physics class you'd know what I mean.

 

I've taken several physics classes. A year of standard physics, a year of physical chemistry (which was heavy into quantum mechanics), and a semester of physical biochemistry in grad school.

 

So let's stop with the condenscending attitude, please, and find that paragraph or some other material that you can use as "data".

Posted

Well my uncle has a compute here so let me explain a little. Sense you've had physics you'll probably understand what I mean.

 

It's the same property just backwards. Instead of the discovered photon telling the other what to be, the undiscovered photon can just as easily be telling the first photon what to be. In quantum mechanics not every mathematical concept converts directly into a sort of cognitive concept. Anybody with a phd in physics will tell you that if you think you understand quantum mechanics, you don't, and these are the sorts of reasons why. I'm just telling gcol there's more to the picture than just the layman explanation, not that your explanation is inadequate.

Posted
Instead of the discovered photon telling the other what to be, the undiscovered photon can just as easily be telling the first photon what to be.

 

:) Or each always knows what it is, and therefore what its counterpart is, but feels no need to wave a placard proclaiming it until some some busy body third party observer sticks his nose into their private lives... Just as well for for the quantum boys the pair don't say "bog off and mind your own business"!

 

 

Thanks to Lucaspa for the text book view and Veedo for the more encouragingly speculative view.

Posted
Well my uncle has a compute here so let me explain a little. Sense you've had physics you'll probably understand what I mean.

 

It's the same property just backwards. Instead of the discovered photon telling the other what to be, the undiscovered photon can just as easily be telling the first photon what to be.

 

Even if this is so, you still have information being exchanged instantaneously in violation of Relativity. And that is the basic "problem".

 

:) Or each always knows what it is, and therefore what its counterpart is, but feels no need to wave a placard proclaiming it until some some busy body third party observer sticks his nose into their private lives... Just as well for for the quantum boys the pair don't say "bog off and mind your own business"!

 

The problem here, gcol, is that people thought of that. So, let's take the L photon and entangle it again with an R photon and then separate them. Now measure the original L photon and it could be R! Did it change? If so, how?

 

Or better yet, take all the L photons and entangle them with other L photons. Then measure and half will be R! And, of course, for those measured as L, the other one becomes an R! How did that happen? They were both originally L. So, they "knew" what they were, did they change their minds? But photons don't have minds!

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Posted
Is it possible that there is a scientific explanation for everything.

 

Nope, some things cannot be answered with testable predictions about the world.

Posted
Nope, some things cannot be answered with testable predictions about the world.

 

It's worth noting that while science cannot explain everything, simply making stuff up cannot viably explain anything.

Posted
It's worth noting that while science cannot explain everything, simply making stuff up cannot viably explain anything.

 

That isn't what we are talking about. People make stuff up in science, too. Actually, come to think of it, every hypothesis is initially made up. And some of them do indeed explain things.

 

No, what we are talking about are the limitations of science. Science is a limited form of knowing. It restricts itself to part of the total of human experience and knowledge. By doing that, science is very reliable in its area, but the price is that science doesn't cover everything.

 

Because science is so reliable in its limited area, there is always the temptation to extend science beyond its limitations.

Posted

Science is a deliberately self-confined form of explanation which restricts itself to predicting the behavior of things in terms of their spatio-temporal qualities, i.e., those that can be measured mathematically. As such, it cannot explain everything and is not designed to do so. Questions which cannot be analysed into spatio-temporal relations and quantified are defined as outside its ambit, so issues of morality, value, aesthetics, existential truths, etc. cannot be answered by science. This does not make these latter issues any less real for human life and society, however, but it just means that their proper resolution is less easily demonstrated.

 

Science can sometimes help clarify the factual material that goes into humanistic and social questions, but that does not reduce these questions to scientific solution. This is why it always seemed ridiculous to me that doctors are expected to have some special expertise in answering issues of medical ethics, which makes as much sense as asking an electrician who should be executed in the electric chair.

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