Forgot your password?
typodupeerror

Comment Re:This is huge (Score 1) 214

Just some quick comments (that is, in terms of how much time I spent thinking about the reply).

Good that we have cleared things up. I can agree with your characterisation if you are more specific about "common cause": what we have to give up is Reichenbach's common cause principle, which is not the only sort of common cause imaginable. In fact, we know the correlations exist because of the entangled state, so the state is some kind of common cause, just not Reichenbach's.

I think that the seriousness of what is given up here has not been fully appreciated. Yes, the results are correlated, but to maintain locality you need to give up the idea that the cause of that correlation is to be found inside the light cone in the past/present. Note again Werner, in the paper you provided, talking about labs bringing their results together, perhaps centuries later. If you stick to locality, then the common cause must be in the future! That is to say, the correlation occurs when the labs bring their results together. It's not just a matter of giving up on some particular notion of common cause. The reason why you need to give up on common cause is because no local, existing in the past cause can explain the correlation. If you think there is an explanation for the correlation, and you think the world is local, then you need to look in the future. That's how I understand the matter anyway, and it fits with what I've read on the topic and why Werner talks at all about labs bringing results together centuries later.

To put this another way: When you look at Wiseman's paper I linked, and reject Principle 25, you give up on the claim that there is a cause of the correlation for entangled particles. If you want to then claim that there is a reason or cause for the correlation, you need to replace Principle 25 with something else. What will you replace it with? If I understand correctly, you will have to replace it with an in-the-future common cause. E.g., when the labs bring their results together. Anything that lies in the past/present light cone will violate Bell's inequality.

Well, for starters, it is hard to reconcile nonlocality and relativity; it requires the nonlocal influences to be some conspiratorial sort that do not actually lead to any superluminal signalling, and I find this conspiracy distasteful.

The reasons why you cannot communicate using these superluminal signals has to do with epistemic limitations. The reasons are not conspirational, and entirely explicable. Perhaps we will one day discover other superluminal phenomena that won't have the same epistemic limits.

Furthermore, it makes the scientific endeavour very suspect, if not actually impossible. A key hability in science is to isolate some system, control its variables, and see how changing them affect the system. In a nonlocal world, the first step of isolating the system is already impossible, so you're not going to be able to have much control over your system, and this reduces what you can learn about it.

This is not a new problem, but something scientists have been grappling with for centuries. (Almost) every system we experiment on now is not fully isolated from the external world. Suppose you're doing research in thermodynamics -- how easy s it to completely isolate your system from the external world? We might be getting better at it, but the fact that we have not been able to do this perfectly in the past hasn't stopped us from exploring our universe. I don't see how a nonlocal world is going to tip us over the edge from making science "very difficult" to "impossible". So far as I am aware, the only non-local event we have discovered so far is with entangled particles. It doesn't seem particularly common, and hasn't stopped us doing experiments like that which this Slashdot post is about.

Overall, compared to the alternative, accepting that the world is non-local still seems like a no-brainer to me :)

Comment Re:This is huge (Score 1) 214

I'm not seeing much of a disagreement with me in your latest reply. For the most part, you appear to be restating in your own words things I've also said. I think we now agree on what the choice is: locality, or common cause. If you want to maintain locality then you have to deny a common cause in these entanglement experiments. That is, even though the 'entangled' particles demonstrate properties that are highly correlated, the correlation nevertheless lacks a common cause. Or, has a common cause that occurs AFTER the experiment is performed (or thereabouts). Do you agree with this characterisation?

And to conclude, I'd like to bet that you are not a physicist (probably a philosopher?), if you think it is in any way tenable to abandon locality.

I'm in favour of letting people see the results of their bets. I have a background in physics, but my main area is indeed philosophy, so well done :)

I would be interested to hear why you think abandoning locality would be a big problem.

Comment Re:This is huge (Score 1) 214

None of this is just 'wordplay'. What's at stake is precisely what one has to commit themselves to in order to reconcile their view of the world with what experiments have shown.

Showing that the world is random/indeterministic at heart is not enough of a sacrifice. If you look at what Werner says carefully, you will see precisely what it is one is required to accept to keep locality:

The state change only becomes effective when the results from the two labs are brought together and are jointly analyzed, which can happen centuries later. Bohmians like Maudlin tend to confuse such changes in distributions with a change in the world, because the notions of states and wave functions are reified, and considered as some real thing out there

Note here that locality is maintained by not having any appropriate change in the world until the two labs bring their results together! This is what I take Wiseman to be referring to when he talks about giving up on correlation. In the Nature article I linked earlier:

But one can go further, by recalling that local causality rests on two principles: Einstein’s principle of relativistic causality, and the principle of common cause. Thus Bell’s 1976 theorem can be restated as: either causal influences are not limited to the speed of light, or events can be correlated for no reason.

...

Those who hold Einstein’s principle to be inviolable (the localists) must conclude that some events are correlated for no reason. A challenge for them is: if correlations do not necessarily imply a cause, when should scientists look for causes, and why?

and from the arxiv.org paper,

In conclusion, for a proper appreciation of the foundational importance of Bell’s theorem to physics, information science, and the philosophy of causation, one should be familiar with both the 1964 Bell’s theorem and the 1976 Bell’s theorem, even though they are logically equivalent. The former proves that quantum phenomena are either nonlocal (in a “causation by agents” sense) or undetermined, while the latter proves that quantum phenomena violate local causality (in a “common cause for correlations” sense).

While Wiseman, Werner, and Maudlin may be all saying subtly different things, their understanding seems to me largely the same. Maudlin shows (as Bell did), that embracing indeterminism isn't enough. What Wiseman points out is that the choice isn't between locality and indeterminism, but between locality and correlation. What Werner says is that the correlation comes from entirely local events, presumably late occuring: when the labs bringing their results together. You have given up on indeterminism, but that isn't one of the options on the table.

As I said before, if indeterminism is the price to pay for keeping lcality, then we're much better off ditching locality. The same goes if one is referring to giving up on correlation of events. But keep in mind the kind of correlation here one needs to give up: it's the correlation we find in the kind of experiment given in this slashdot article. These are very *strong* correlations. How crazy does a view have to be before we give up locality?

Comment Re:This is huge (Score 1) 214

Maudlin shows in the book I referenced how local indeterministic theories also violate Bell's inequality. But it's not just Maudlin: Bell himself proved what Maudlin claims. Howard Wiseman thinks that the confusion comes about for the reason that Bell had two papers. The first paper in 1964 argued from the twin premises of locality and determinism, leaving the impression that one could give up just one of these. In his 1976 paper, Bell made it clear that the problem derives from locality alone. Wiseman writes:

In 1976, Bell proved that his new concept of local causality (based implicitly on the principle of common cause), was ruled out by Bell correlations. In this 1976 theorem there was no second option, as there had been in the 1964 theorem, of giving up hidden variables. Nature violates local causality.

Maudlin is not mistaken, and is not alone. A more detailed paper by Wiseman: http://arxiv.org/pdf/1402.0351v2.pdf.

Comment Re:This is huge (Score 1) 214

Assuming I have the phrases around the right way, I meant that local stochastic theories violate Bell's inequality, just like deterministic local theories do. It is a common misunderstanding, even among physicists, that experiments like these have shown trouble only for local hidden variable theories. The fact is that Bell's inequality is violated by any account you like -- stochastic or deterministic -- so long as you insist on locality.

Locality is the problem, not hidden variables. I completely understand that you're not going to read a book to see my point defended. People are busy, and I only posted it in case you wanted to see. You could also check out a paper by the same author which I think will discuss the matter, but I haven't read this paper myself.

One final note. Suppose that in fact we had to choose between indeterminism and non-locality. I think that indeterminism is the crazier of the two options by a long shot. Non-locality can be understood, while indeterminism is, by its very nature, incomplete. If it came down to a choice between the two, non-locality should win hands down. At any rate, it doesn't matter. The universe is shown to be non-local by these experiments anyway, regardless of your views on determinism.

Comment Re:This is huge (Score 1) 214

Violations of Bell's inequality do not show that the universe is not deterministic. They show that it is non-local. Even stochastic theories violate Bell's inequality when they insist on maintaining locality. Bell promoted a deterministic interpretation of Quantum Mechanics -- pilot waves -- that have all the same experimental predictions as the typical indeterministic interpretation.

Whether you think the world is deterministic or stochastic at heart, you have to give up on locality. The book 'Quantum non-locality and relativity' by Tim Maudlin shows how even non-deterministic local theories violate the inequality.

Comment Re:Why is nobody talking about the potential (Score 1) 214

Violations of Bell's inequality do not show that the universe is not deterministic. They show that it is non-local. Even stochastic theories violate Bell's inequality when they insist on maintaining locality. This is a common misunderstanding of Bell's inequality. Bell himself was a determinist about these matters, and promoted a pilot wave interpretation of Quantum Mechanics.

Comment Re:Wait, physics doesn't work either? (Score 1) 214

Bell's inequality shows that both local hidden variable AND stochastic theories cannot reproduce the observations of quantum mechanics. Bell's theorem showed that the universe is non-local, regardless of your preferred interpretation. Bell himself promoted a pilot wave interpretation.

Many people have misunderstood Bell's result to be saying something against hidden variable theories. It isn't. It is saying something against locality.

Comment Re:A null hypothesis must be falsifiable (Score 1) 556

It can ignore physical laws, and even causality or logic. Under such a deity, it is completely valid that the world was both created yesterday, and is 13.6 billion years old.

I would be careful about a claim like this. I think it's important when investigating a substantive position that you look at the best formulation(s) of that position (principle of charity). And while some people have claimed God can do the logically impossible, I suspect that among well informed, intelligent, theist academics, the prevailing view would be that God cannot do the logically impossible. That is, omnipotence is defined (crudely in this post) in terms of God's ability to do all that is logically possible. So when someone says "God can do anything", by "anything" they mean "any possible thing" (does it even make sense to say that God can do the impossible? In what sense, then, is it impossible?).

Comment Re:A null hypothesis must be falsifiable (Score 1) 556

That is not what a null hypothesis is at all. A null hypothesis must be falsifiable.

From that wikipedia page:

In statistical inference on observational data, the null hypothesis refers to a general statement or default position that there is no relationship between two measured phenomena.

Just so I understand you clearly, could you please point out which are the two separate measured phenomena (with regards to God's existence) that we are investigating for a relationship?

I am interested in questions about how we should reason about things, how we should determine what things we should believe, which hypotheses are best supported, that sort of thing.

Now, suppose we have two phenomena, A and B. The null hypothesis claims that our default hypothesis should be that there is no relationship, and then our job is to then 'prove' that hypothesis false. But then there is this important question -- if the null hypothesis is our default position, why would a scientist *ever* think to investigate whether or not there is a relationship between A and B? Such a scientist, you suggest, believes that there is no relationship.

There are a multitude of phenomena in the world, many orders of magnitude more than there are man-years to investigate relationships between. Scientists need to be careful to choose the most promising phenomena pairs for relationships. And if scientists can do that, then there must be some separate method of inference that we humans have that allows us to pick the candidate phenomena most likely to have a relationship. And what does that mean? That the "null hypothesis" is simply a particular tool in a particular field of inference, or a professional practice, that is not representative of the best approach to inference, but rather a useful approach in particular cases. It doesn't tell us what the scientist believes. In fact, the scientist choosing to investigate two particular phenomena indicates that the scientist believes there may be some such connection.

You would need to then establish that the null hypothesis is the right position for belief.

Comment WSJ right to not publish Krauss' response (Score 1) 556

There are serious concerns with many versions of the fine-tuning argument, but Krauss raises none of those concerns. Instead, he raises the sorts of objections that someone unfamiliar with claims about fine-tuning would raise, objections that would be covered in a "first, let's quickly set aside all the bad objections to fine-tuning arguments so we can get onto the interesting parts" section of a lecture. His response is the work of an intelligent person who thinks that just because they're an expert in one area, they must be an expert in all.

Why should the WSJ publish rubbish like that?

Comment Re:A Simple Retort (Score 1) 556

Proofs are for mathematics and logic. For empirical questions of the sort you propose, you can prove neither the affirmative nor the negative claim -- there is always room for a sliver of doubt. There is nothing special in this regard about the hypothesis that God exists.

The original WSJ article is a non-scientist claiming that science has indeed proven the existence of god

I can't seem to get the full article without paying. Are you able to quote the line, for my benefit please, where the author claims that science has proven the existence of God?

Comment Re:Widespread religion (Score 1) 1142

There is absolutely no relation between thermodynamics laws and the need of an external entity. There is no guarantee that the universe is eternal and not even that it had a beginning, but even if any of these concepts could be proved it wouldn't still imply in the existence of any external factor.

Why precisely do you think there is no connection? The low-entropy boundary condition of our universe is enormously unlikely by probabilistic analysis. Why would a universe devoid of God conspire to create such a low-entropy condition? God, on the other hand, would prefer low-entropy universes. That means that low entropy counts as evidence more strongly confirming theism over atheism.

And as for the universe having a beginning not implying the existence of any external factor, the only reason I can think you'd believe that is if you think some things exist without reason. And in this case the theist is doing better, because he is not content with non-answers - he wants to get to the truth of the matter. The atheist, on the other hand, often seems content to sit on no reason, no answer, as the explanation for something. I think that's telling, for those who typically pride themselves as the ones not satisfied with non-answers. As for me, I find Leibniz' Principle of Sufficient Reason quite compelling, and if atheism means discarding it, I'll stick with theism.

Comment Re:Widespread religion (Score 1) 1142

What happened in the soup was about replicator protien chains. Not life. These chains were behaving no more magically than the letters that clump together in your alphabet soup. But somewhere, in a huge ocean with a density near 6.02 X 10^23 particles per 18 grams, there was a combination of alphabets that was stable, and that attracted "letters" to it, that would create another chain like it on the outside, and with a bit of wave action, split and repeat the process. Still, not life, but a replicator protien that (if you read the book) would one day become life through a gradual series small changes.

If you read the book and understand the basics of organic chemistry, it not only seems plausible, but unavoidable.

Preposterous. And at any rate, I have heard Richard Dawkins himself state a few times recently that the formation of any life seems so improbable, that he doubts it has occurred anywhere else in our universe. So either his book does not imply that it's "unavoidable", or he has since changed his opinion on this matter (I can't answer, since I have not read the book).

And just for the record, atheists kill people too. I find it disconcerting but very unsurprising how many atheists I encounter tell me that there is no such thing as right and wrong, but it is of pragmatic value for them to behave well. Does that sound like a better foundation to you for world peace? Sure, it doesn't describe every atheist, but to think that religion is THE source of violence, and removing it would fix these troubles, is just more nonsense.

Comment Re:Call me when we have instant transfer of data (Score 1) 156

However entanglement is useful for other things. Like networks where you can detect if someone snooped on your packets.

I don't quite understand this, but maybe I'm just missing the details of the practical application you have in mind. If what you mean is that you have one of the entangled pairs, and you have the other one in transit, and you can look at yours to see if the in-transit one has been snooped on, then this would allow faster than light communication, wouldn't it?

Have some entangled particle emitter at a midpoint between you and the person you are communicating with, and have the emitter emit a constant stream of pairs, one to you and one to your friend. Let "someone snooped on my packets" = 1, and "my packets have not been snooped" = 0. Your friend then snoops on your packets at appropriate intervals when they reach him, in order to send a sequence of bits corresponding to a message. You then observe your particles to see if they have been snooped on or not. That would be faster than light communication, if you could indeed detect from one paired particle if the other had been snooped on or not.

Slashdot Top Deals

Lead me not into temptation... I can find it myself.

Working...