This question arose out of an article in New Scientist discussing BB in cosmology. My question is: why would the existence of BB threaten the view of humans as 'typical' observers in the cosmos? The article implied that BBs would experience different laws of physics than 'typical observers' would, necessitating what looked to be very convoluted explanations as to how the universe would expand/bud off/constrain our ability to observe phenomena to local spacetime such that the existence of BBs (should they ever pop into being) would not threaten the equivalence of the laws of physics for all observers.

Could somebody please explain this to me? I must have been asleep when BBs were discussed in my astrophysics and/or quantum mechanics classes.

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The dose makes the poison--Paracelsus (1493-1541) http://en.wikipedia.org/wiki/Paracelsus

I don't know. That's why I'm asking--Noclevername

Intelligence may not be clearly defined, but you know stupid when you see it--Noclevername

Science is a way of thinking much more than it is a body of knowledge--Carl Sagan (1934-1996)

Paracelsus, you're on a roll today

Yeah, I know.

I'm so busy during the week that I rarely get to post, and I feel so crappy today (bad asthma attack) that I don't want to do anything but surf the net.

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The dose makes the poison--Paracelsus (1493-1541) http://en.wikipedia.org/wiki/Paracelsus

I don't know. That's why I'm asking--Noclevername

Intelligence may not be clearly defined, but you know stupid when you see it--Noclevername

Science is a way of thinking much more than it is a body of knowledge--Carl Sagan (1934-1996)

I've never heard of "Boltzman's Brains", it sounds like a peripheral science avenue, like the anthropic principle.

I hadn't either, but apparently some cosmologists theorize that they could exist: http://en.wikipedia.org/wiki/Boltzmann_brain

A disembodied brain that arises out of the 2nd law of thermodynamics??

Far out!

So to speak..

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The dose makes the poison--Paracelsus (1493-1541) http://en.wikipedia.org/wiki/Paracelsus

I don't know. That's why I'm asking--Noclevername

Intelligence may not be clearly defined, but you know stupid when you see it--Noclevername

Science is a way of thinking much more than it is a body of knowledge--Carl Sagan (1934-1996)

I see. But that argument would hold more sway if we knew nothing else about humans or consciousness or entropy! In fact, we see all kinds of self-organizing systems that don't wait around for entropy fluctuations-- they create their own entropy fluctuations. In other words, we already know our brains are not the result of stochastic fluctuations-- they are the result of genetic evolution.

Yep, I agree. But some cosmologists don't. :shrugs:

I think it sounds like a bunch of hooey myself.

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The dose makes the poison--Paracelsus (1493-1541) http://en.wikipedia.org/wiki/Paracelsus

I don't know. That's why I'm asking--Noclevername

Intelligence may not be clearly defined, but you know stupid when you see it--Noclevername

Science is a way of thinking much more than it is a body of knowledge--Carl Sagan (1934-1996)

I've been thinking about this possibility a bit recently; the Boltzmann brain is supposed to emerge, or appear, as a consequence of a random fluctuation. In this way it might be similar to, but smaller than, an entire universe.

The theory is, (as far as I can tell) that many diiferent entities will emerge over time as a consequence of quantum fluctuations; the most common will be virtual particles, but they will range in size and complexity through macroscopic objects, black holes, Boltzmann Brains and eventually entire universes capable of supporting evolution.

Since these things occur at random, the more complex they are, the less likely they are to occur- that is, you will have to wait longer for a Universe to appear than for a Boltzmann Brain to occur.

Boltzmann brains would outnumber universes by a vast amount; so on the face of it the likelyhood is that any randomly selected thinking being is a Boltzmann Brain floating in a sea of chaotic virtual particles, a mind which could be supplied (by chance alone) with false memories of life in a real universe.

But- this doesn't take into account the vast potential of a real universe. Bazillions* of thinking beings can emerge by evolution in a suitable universe; with a certain amount of luck and hard work, the matter that our own universe is made of could eventually be mostly converted into processing material, capable of supporting a huge number of entities with a real universe to exist in. And it is possible that there might be even more complex universes out there, even more capable of supporting thinking entities than our own.

At the end of the day, such universes could be crammed full of thinking entities ( I think they are called Ordinary Observers, in the jargon).
Such universes themselves will be rare compared to Boltzmann Brains, but if you count the number of Ordinary Observers in each of these universes they could outnumber Boltzmann Brains in the long run.

*a large number you are welcome to calculate yourself.

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same here. I'm still trying to wrap my own brain around that.
It Burns us!

That requires that it be established a Boltzmann Brain has a higher random probability than a universe that can support genetic evolution. I highly doubt that, and cite the way evolution builds originally quite simple things and only later more complex ones.
Even if this were true, the "anthropic hypothesis", which is basically that we should expect our consciousnesses to be somehow "typical" (i.e., we should expect to be Ordinary Observers), is not a scientific principle and is on very uncertain logical footing as well. Many scientific thinkers believe in it, that's true-- but not based on evidence.
That is exactly the kind of problem you get into when you adopt the anthropic hypothesis-- how do you count minds? If they have to be able to ask that question in order to count, then what will count as that question? Do they have to come up with the question themself to count, or can they be instructed in it? Can a computer program be so instructed? What language shall be the standard? I don't see it as a scientific mode of thought at all.

Is this anything like the bolted-on brain?pete

see:http://cache.jalopnik.com/cars/asset...ankenstein.jpg

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A second rate theory explains after the fact.
A first rate theory predicts.
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It was not the best New Scientist article ever. The fundamental idea is that over astronomical time, if the universe is infinite, and if it is expanding, and if it doesn't rip itself apart, and if it lasts long enough, there is some non-zero probability that reasoning 'brains' that can observe the universe might pop into existence. Given satisfaction of the string of 'if's' above, I would agree that it is possible. But who knows how long it would take? 10 to the 100 gigayears? We'll be long gone before then. It's idle back of the envelope speculating during coffee break at the physics department.

How can anyone calculate the probability of a BB emerging? Surely that would require such a fine understanding of the concept of conciousness (in a universal sense, not just human conciousness) as to be able to say this lump of exotic matter is concious and that one is not.

Do we really understand well enough how conciousness arises to be able to differentiate between the two?

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"I worry that, especially as the Millennium edges nearer, pseudo-science and superstition will seem year by year more tempting, the siren song of unreason more sonorous and attractive." - Carl Sagan, 1995

BBs are a piece of fairly typical radical skeptical argumentation. As such, there really is no place for them in rational discourse.

The real problem is that, regardless of whether or not we are BBs, we can't reasonably act like we are BBs. Our reasoning is based too much on our assuming that it is reasonable to base our knowledge on what we remember from the past and that it is reasonable to gain information from what we can observe of the past of our universe. Even the process of figuring out what a BB is relies on our knowledge of physics, which relies on our assuming that we aren't a BB.

Ah, but if we were BBs, we'd have false memories of past lives...which could include false memories of being physicists and carrying out observations..which would lead to the assumption that we are not BBs when in fact we are and we are just imagining remembering talking to each other on an imaginary online forum called 'BAUT' when we are actually doing nothing but floating around in space as disembodied brains in a dead, decaying universe...

**head explodes**

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The dose makes the poison--Paracelsus (1493-1541) http://en.wikipedia.org/wiki/Paracelsus

I don't know. That's why I'm asking--Noclevername

Intelligence may not be clearly defined, but you know stupid when you see it--Noclevername

Science is a way of thinking much more than it is a body of knowledge--Carl Sagan (1934-1996)

If a random fluctuation in entropy can spontaneously produce a brain, it can also dissipate it immediately... whether that brain saw it coming or not...

I'd say the very premise itself, that BBs are more likely or easily generated than evolved societies of intelligences, has not been established in the least. Personally, I find it absurdly unlikely that a BB would appear spontaneously-- it takes a lot more entropy control to generate a whole civilization of brains, it's true, but that's what evolution is all about. Once you get the template, it's off to the races-- billions and billions of real brains that don't rely on "fluctuations". I think Boltzmann is all wet on this one.
That's also true-- the premise is not only unsubstantiated, and seemingly highly unlikely, but it is also useless. That's three strikes in science baseball.

Cumulative positive feedback! We came from not just one entropy fluctuation, but a pile of many of them in the past that have each created the next one. It doesn't make sense to expect a comparable result from just one single incident.

Some comments here about infinities, which is about all that I can think of that BB speculation is worth.

1. In an infinite universe, anything that can happen, will happen.

2. Our universe, as far as we know, is infinite.

3. For you fans of Fred Saberhagen, that means that somewhere in our universe, there are Berserkers.

Nighty-night, sleep tight!

These statements are not necessarily wrong, know one knows, but they don't necessarily follow from logic.Even in an infinite universe, there could also be an infinity of things that don't happen too. For example, the even numbers are an infinite set, but include no odds.We have no idea if the universe is infinite or not, there is simply zero evidence either way. It is unknown, and it looks like it will stay that way.

As I see it, the issue is that our understanding of entropy is flawed, as it assumes things always tend toward's randomness.

Yet the world is absolutely full of examples of self-organization, including life.

But that's not all that's self-organizing.

Let's take mountains, for example. Entropy seems to say that they'll eventually erode, but what do we actually observe? We observe that some are getting smaller, while others are getting higher. Sure, the tops are eroding, but it's not all random chaos, as the energy contained in tectonic activity pushes them up.

Nor are they randomly scattere, but instead, they tend to form in ranges - self-organizing according to basic principles of physics.

Pretty much everything is self-organizing, but what's the source of the self-organization? It's an inherent quality of matter itself, that when matter contains energy, it tends to self-organize. Take waves in water, for example. Wind energy imparted to the water develops waves which travel in a fairly uniform manner. One might say that mountain ranges are simply tectonic waves, or that DNA is a chemical wave brought about by a lot of complex interactions of matter.

Entropy seems to suggest that everything tends towards chaos, but again, we observe that the opposite is true - matter tends to self-organize when it's provided with energy.

Sounds like a subset of Alex Vilenkin's new cosmological model.

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Everyone is entitled to his own opinion, but not his own facts.

I did hedge and say "can happen." Even as an infinite set, the even numbers are still a proper subset of all integers.

From Wiki, “Cardinal arithmetic can be used to show not only that the number of points in a real number line is equal to the number of points in any segment of that line, but that this is equal to the number of points on a plane and, indeed, in any finite-dimensional space. These results are highly counter-intuitive, because they imply that there exist proper subsets and proper supersets of an infinite set S that have the same "size" of S, although by definition they are not equal to S (i.e. S contains elements that do not belong to its subsets, and the supersets of S contain elements that are not included in it).”

I would agree that, for example, even in an infinite universe there will be no electrons with non-quantized spins.

But, in an infinite universe, anything that can happen (that is, is not forbidden by the laws of physics), will happen. And as far as we can tell, the laws of physics are the same everywhere in our universe.

Berserkers are not forbidden by physics. Fortunately, FTL travel is. Let us hope that highly improbable events don't occur anywhere near us.

Considering that we see no limit to the universe other than opacity limit of early universe, and that limit is probably still 13 billion light years distant in all directions even if we are 13 billion light years away from here, then I would argue that given what we observe, assuming that the universe is infinite is the simplest solution.

The principle of entropy makes no such assumption, that's a misconception. All it says, in a nutshell, is if there are ten ways that your room can appear tidy, and a thousand ways that it can appear messy, and each of those ways is equally likely to occur if left on its own, then your room will be a hundred times more likely to appear messy than tidy. That's it, that's the principle. What counts as tidy or messy is up to us, the principle doesn't specify that, nor does the principle say that all those various ways are equally likely-- we have to set up the problem so that they are, or we're not invoking the principle properly. The principle of increasing entropy is as inevitable as logic itself.

What you are talking about is the common misconception that if entropy is to increase, you cannot find order anywhere. That is not correct. The principle applies to the entire closed system, not to subsets. It is well known that subsets of the total system can reduce their entropy, we see it all the time. In the messy room analogy, it would be like introducing a maid into the system. The maid will sweep the dust and pick up the mess, thereby apparently increasing order and putting the system into a less likely random state. But now the maid is also in the system, so we have to look at everything that is happening. The maid ate lunch first, which involved chewing up nice ordered chemical bonds. As the maid is dusting, he/she is breaking those bonds, extracting energy, and generating heat. What that heat does is it takes the molecules in the room and gives them access to more disordered ("hotter") states than they were in before. And lo and behold-- when the maid leaves the room, it is in a less orderly state than when she came in! The books are on the shelves, maybe even in alphabetical order, but the air molecules are more random as a result-- and the latter effect always dominates the former, in the total. That's the second law of thermodynamics in action.

What's really interesting about this is, you can ask, how was the maid able to do that-- how was he/she able to organize one part of the room at the expense of the molecular order in the air? The answer is shockingly simple-- he/she simply gave the total system access to a more likely configuration than it had access to before! Given that access, the rest takes care of itself, automatically. There are simply more ways that the room can look like it did when he/she left, than there were ways it could look like that messy pile she entered! The room was always "happier" to look the way it ended up, given the inclusion of the added heat, but it simply did not have access to those more likely states because it required energy to get there. That's self-organization in a nutshell-- the use of energy to give an overall system access to a more likely configuration, even though subsets of that overall system may end up being in less likely configurations. There is no violation of the law of entropy there-- that is the law of entropy in action.
It's all what I'm saying-- addition of energy allowing an overall system to reach a more likely configuration even if parts of it reach less likely configurations. There always has to be more ways it can end up than the ways it started-- that is the very meaning of the word "spontaneous"-- it controls what happens spontaneously: whatever is most likely subject to all the other constraints that are in place. A lot of people mistake spontaneous activity for something that requires an external influence-- because they don't realize that as soon as you place that "external" bit into what you are calling the system, what you are left with is entirely spontaneous behavior. That's called statistical physics, one of the least understood areas of physics by most people (a lot of people understand quantum mechanics better than statistical physics!).

Nope, it really is all random chaos, when the "system" includes everything that can influence the mountains.
Entropy. Your argument is correct, you have simply used it to infer exactly the opposite of what it actually gives!

And that is precisely what the correct interpretation of the theory of entropy says it will do.

I don't know much about that, it sounds interesting. But I will be cautious in clearly defining what I mean by a "model" before I will agree that this is what he has!

What about "entropy always increases in a closed system"?

If that is really the answer, why do you think Stuart Kauffman took 709 pages to explain it in his Origins of Order?

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Everyone is entitled to his own opinion, but not his own facts.

Yeah, that's just what I'm saying. Saying that entropy increases is the same as saying the system will spontaneously evolve toward configurations that can happen in a larger number of equally likely ways, because that's just obviously what they will do. Entropy is the Boltzmann constant times the natural log of the number of equally likely ways a particular indistinguishable state of a system can be obtained, subject to the various constraints in play.

I can't speak for Stuart Kauffman, perhaps he is not a very concise writer! Or maybe he was interested in examining all the ramifications and all the various ways order can result-- applications, if you will. There are always a lot of those.

If the universe is infinite, then there is an infinity of events that have yet to happen. In other words, in an infinite universe, most things that can happen haven't happened yet.

In fact, most things that can happen will never happen in an infinite universe.

Because no matter how many things that have happened in the past, there is still an infinity of things that could happen in the future.

Pretty much everything we observe is self-organizing, because if a system is not self-organizing, then, logically, it must be self-disorganizing. Self-organization cannot be an inherent quality of matter because things fall apart all the time.

So what's the source of self-organization? Good Design honored and honed by Natural Selection. Which goes on in the physical domain as well as the biological domain, as George Perkins Marsh pointed out in 1864. Things that don't have a good design don't tend to last very long, and that's why we don't see them much.

I think Richard Dawkins once said "There are more ways to be dead than to be alive." We could generalize this and say that there are more ways Not To Be than To Be.

Hence the question: "Why is there anything rather than nothing at all?"

The fact is that nothingness is the most statistically likely situation. We don't see it. Why? Because of Good Design and Natural Selection. That's why the Anthropic Principle is so useful. It takes for granted that the universe is well designed, and then sees what falls out as a result of that assumption. Nothing unscientific about teleological assumptions--they are made everyday in biology; they are merely unfamiliar to physical sciences. To say it really is all random chaos even considering the system as everything, is not very explanatory.

Yeah, that gets into the whole anthropic principle business. Personally, I think that way of thinking is fine for getting a "warm fuzzy feeling", but real science operates under more constraints than that-- it just accepts that you always have "initial conditions" that are outside the theory you are applying. If we want to develop a "science of initial conditions", we are entering murky waters, and threaten to undo much of what the scientific revolution has accomplished by sticking to its own paradigm.
That does explain why we see order in some places, at the expense of disorder somewhere else. But you still have to have "something" to have any of that.

Useful for what? As a scientific principle, it is useless, but as a philosphical reassurance, it's fine.

No, simple observation tells us what "falls out". The anthropic principle makes no testable predictions, it is all a posteriori logic to achieve a sense of reassurance. We don't need the reassurance-- there are simply mysteries. That's the skeptical stance, ironically.
They are not unfamiliar in physics, they are unnecessary in physics. Teleology is a far more basic concept than what are used in physics, it is like anthropomorphization. Biology finds it useful in the context of natural selection, physics does not find that useful. For example, when we study what holds a crystal together, we do not say "well we could have all kinds of forces that wou ldn't hold the crystal together, so we learn something about the forces that can." No, we simply study the forces that do hold it together, you can call that teleological function if you like but it doesn't add anything to the discussion that wasn't already there. That's always the problem with anthropic thinking.I agree, but we must avoid the temptation to look for "explanations" we cannot support scientifically, within the constraints of the science that got us here. We do not want to return science to the more philosophical realm of the ancients. Science is stuck with what happens spontaneously because it is the most likely result-- that is the core structure of modern physics, from quantum mechanics to cosmology, and we shouldn't start changing that now.