Fine-tuning

[Nelson]

I'm not sure if anyone follows Sean Carroll's blog or not, but here you go:

http://blogs.discovermagazine.com/cosmicvariance/

He is a fairly well known physicist and author, and he has just submitted a paper on fine-tuning related ideas. I am printing it now. It looks pretty dense, but I'm going to try to make my way through it. I'm not sure I follow his reasoning in the blog post.

In English: our universe looks very unusual. You might think we have nothing to compare it to, but that's not quite right; given the particles that make up the universe (or the quantum degrees of freedom, to be technical about it), we can compare their actual configuration to all the possible configurations they could have been in. The answer is, our observed universe is highly non-generic, and in the past it was even more non-generic, or "finely tuned."

The point where I get lost is how you can say that all of said configurations are equally likely. Perhaps this is addressed in the paper itself. Here it is:

http://arxiv.org/abs/1007.1417

Fine-tuning seems to be a popular argument in the creationist world, so I thought perhaps others would be interested in this sort of thing as well. I'll reserve judgeship until I actually read the paper however. I think the real conclusions will come down to what he also mentions in the blog post:

One way of describing this state of affairs is to say that the early universe had a very low entropy. We don't know why; that's an important puzzle, worth writing books about.

This seems to be the real question here, but there should be some interesting physics wrapped up in all of this, and Sean is usually quite good at explaining things.

 

[Demojen]

They destroyed the theory of a finely tuned universe for me with the destruction of the flagellum argument for Irreducible Complexity.

 

[TheFlyingBastard]

"That it could have been in"? To me that doesn't seem to solve the issue of sample size = 1.

"Well, this poll about religion only had one response by a Christian, but we it could have been 60 Christians, 25 Muslims and 450 atheists. That would show us that being religious now makes you part of a minority. Stop the presses!"

 

[borrofburi]

In English: our universe looks very unusual. You might think we have nothing to compare it to, but that's not quite right; given the particles that make up the universe (or the quantum degrees of freedom, to be technical about it), we can compare their actual configuration to all the possible configurations they could have been in. The answer is, our observed universe is highly non-generic, and in the past it was even more non-generic, or "finely tuned."

The point where I get lost is how you can say that all of said configurations are equally likely.

You can't, at least not with any serious merit. I have a rock sitting on my desk, compared to all the possible configurations this rock *could* have had, this one is highly non-generic, and could have only come about if a deity specifically put every molecule there, it's too unlikely not to have an intelligence behind it... Of course, I have to ignore all the physics and chemistry behind rock formation, and the entropy based reasons why this formation of molecules into a rock is not all that unlikely, in order to write a paragraph like that; but the reason we know this specific arrangement of molecules that I call a "rock" is rather likely is because our sample size is greater than one, and we know the physical forces that compel these molecules to combine like this. This is not so for our universe; indeed, our universe may be very likely due to some sort of universe-forming physics that we can't interact with to understand.

"That it could have been in"? To me that doesn't seem to solve the issue of sample size = 1.

I think this is like the 4th or 5th time you've beaten me to a point...

 

[Nelson]

So, let me preface this by saying that I am an atheist and have no intention of arguing for the point of fine-tuning by any sort of designer. If that is how my original post appeared, then I apologize, this is not the case. I am more interested in if the question itself is actually meaningful. In general, can we learn anything about the array of possible initial states of the universe from within the universe? Everyone responding so far seems to think that it is a trivial matter to dismiss this question as unanswerable, but I can conceive of a universe which, within itself, contains information about it's formation.

It seems simply ridiculous to stop before even tackling the question and say, "this is fundamentally unanswerable". The only way to do this is to define the universe as everything we could possibly ever interact with or gain information from. In this case you are just making a semantic argument and defining the universe in such a way that questions about the origins of the universe are obviously unanswerable. If you want to use this definition, then we can stop here. Yes, I agree, questioning the origin of a universe with that definition is meaningless. The definition of the universe being used by most physicists tackling this question is: the 4-dimensional space-time that we currently understand and perceive. This is clearly what Sean is discussing in the paper (although I haven't read the whole thing yet, we are having nice weather in BC ).

Let me also make it clear that I am not saying, "oh gee, isn't it strange that life exists in a universe that is able to support life?" If the question of the probability of a universe like this arising is in fact answerable, and it turns out that this universe is for some reason extremely atypical, the logical conclusion would seem to be that we are part of some larger multi-verse, or that the universe itself is cyclical. Really, I am just asking, "is it possible to probe what sort of larger structure encompasses this 4-dimensional space".

 

[Deleted member 619]

It's only fundamentally unanswerable if we never find a way to view other cosmic expansions. In other words, we would require evidence that these other configurations could actually exist in reality, rather than as some kind of thought experiment, in order to lend any credence to the idea that they could actually be any different. He's postulating 'possible configurations' without knowing what's actually possible. There is no good reason to give any weight to arguments concerning fine-tuning, regardless of the source. It doesn't matter whether he's a physicist or Kalamity Craig.

 

[Unwardil]

It gets even more complicated because not only would we have to be able to observe other different expansions, but we'd also have to prove that life couldn't exist within those expansions before there is any reason to suppose that our universe has been fine tuned for life.

 

[nemesiss]

the only thing fine-tuned is his bullshit argument to sound plausible.

 

[DepricatedZero]

Didn't Andromeda's Wake just do a video about this. . . ?

 

[IBSpify]

The fine tuning argument hinges on the argument that if the constants were different then life would not exist.

The problem is they can't prove that it would even be possible for the constants to be any different, they also can't address the argument that life in another form could arise under these new constants, it might not be human life but who is to say that it's impossible for life to exist under different circumstances.

When they get into probabilities they run into the issue that we are working with a sample size of 1, and as such probabilities are meaningless.

 

[Nelson]

Ok, so it appears we have some confusion with regards to the term fine-tuning. Fine-tuning in this case does not refer to the ability to sustain life. The ability for a universe to sustain life is not discussed at all in the paper. In the context of the paper I originally linked, the term is used to describe universes which are flat. This has to do with the critical density of the universe, and why it appears to be so close to 1. Inflation solves this problem, so the question then becomes: how likely is a region of space to undergo inflation?

As far as I can tell, most of the responders have not even glanced at the blog post, or the paper itself, or this would have been immediately clear.

Everyone seems to believe I am some sort of theist attempting to put forward the argument that something about the universe makes it appear designed. Let me make it clear, this is light years from the truth. I have already stated that I am an atheist, I am in no way supporting the argument that the universe is fine-tuned for life, or that we should be surprised even if this is the case. The paper is about the flatness problem.

the only thing fine-tuned is his bullshit argument to sound plausible.

Aggressive much? I'm not sure what I did to piss you off, but there is certainly no need to be a dick.

 

[Deleted member 619]

Three things:

1. I made no connection with life.
2. I don't need to read the blog post. All assertions of fine-tuning are horseshit. Tuning is an act of will.
3. It makes no difference to me whether you're an atheist or a theist. I was addressing the fine-tuning bollocks only.

Oh, and being a dick is practically a qualification.

 

[Nelson]

Three things:

1. I made no connection with life.
2. I don't need to read the blog post. All assertions of fine-tuning are horseshit. Tuning is an act of will.
3. It makes no difference to me whether you're an atheist or a theist. I was addressing the fine-tuning bollocks only.

Oh, and being a dick is practically a qualification.

Do you understand the difference between the standard big bang model and inflationary cosmology? By your reasoning, inflation is entirely unnecessary, and many physicists have spent their entire careers on a pointless endeavor. The entire point of hypothesizing a period of inflation was to explain the presence of two apparent fine-tuning problems. Those are:

The Flatness Problem

The Horizon Problem

For example. We discover that everywhere on the sky, there are regions that have the same temperature of microwave radiation to one part in 10^5. However, given our standard big bang model, these regions were never within one another's light cones. They could not have exchanged energy. So the question is, how did the entire sky equalize itself like this? You're answer is, "that's just the way it is", but physicists HAVE moved forward with this question, and inflation does a good job of explaining this sort of thing.

It seems to me that you can always reach a point and say, that's just how it is. I am reluctant to throw in the towel so easily.

Edit:

I believe this definition will be useful as well:

http://en.wikipedia.org/wiki/Fine-tuning

This is the sort of definition used by physicists when discussing the examples I have given.

 

[Deleted member 619]

Do you understand the difference between the standard big bang model and inflationary cosmology?

Yes.

By your reasoning, inflation is entirely unnecessary, and many physicists have spent their entire careers on a pointless endeavor.

Err, excuse me, but how does that follow from what I said?

The entire point of hypothesizing a period of inflation was to explain the presence of two apparent fine-tuning problems. Those are:

The Flatness Problem

The Horizon Problem

Bzzzzzzzzzz. Thank you for playing.

The horizon problem is nothing to do with fine-tuning. It's an issue with the isotropy of the universe and the transmission of information.

As for the flatness problem, that is meant to deal with an apparent issue of fine-tuning. Only problem is, there is no good reason to suppose that there is any fine-tuning. Please xpose your ignorance some more. We could do with a laugh.

For example. We discover that everywhere on the sky, there are regions that have the same temperature of microwave radiation to one part in 10^5. However, given our standard big bang model, these regions were never within one another's light cones. They could not have exchanged energy. So the question is, how did the entire sky equalize itself like this? You're answer is, "that's just the way it is", but physicists HAVE moved forward with this question, and inflation does a good job of explaining this sort of thing.

Again, that's fuck all to do with fine-tuning, and is to do with isotropy and the superluminal transmission of information. And yes, inflation does present a useful model to deal with this, but it still has nothing to do with fine-tuning.

It seems to me that you can always reach a point and say, that's just how it is. I am reluctant to throw in the towel so easily.

Ph, so you think that's what I'm doing? You expose your ignorance some more. Until such time as fine-tuning is rigorously demonstrated, there is no good reason to suppose it exists. Further, Guth's inflationary model is only one of the models on the table. There are others and, while Guth's hasn't been falsified, neither have the others. Inflation is a useful model, but does not enjoy the position of being the accepted cosmology, or even close to it.

Edit:

I believe this definition will be useful as well:

http://en.wikipedia.org/wiki/Fine-tuning

This is the sort of definition used by physicists when discussing the examples I have given.

Thanks for the lesson in cosmology. Do you teach your granny to suck eggs for an encore? Fine-tuning has not been demonstrated, and there is no evidence to suggest that the constants of our cosmic expansion could be any different than we experience. I am perfectly well aware of what physicists discuss, this being one of my major areas of interest, but that is all utterly irrelevant until or unless fine-tuning can be empirically supported. Good fucking luck with that. Your Nobel prize awaits.

Any appeal to 'physicists' in this instance is a vacuous appeal to authority, not least because there exists no such thing as an expert in this field, because there is no fucking evidence upon which to base expertise, capiche?

 

[Nelson]

As for the flatness problem, that is meant to deal with an apparent issue of fine-tuning.

The entire point of hypothesizing a period of inflation was to explain the presence of two apparent fine-tuning problems.

(underline added)

As you can see, this is exactly what I have said. I am not stating that anything is actually fine tuned. In all of the cases that we have come across, the answer has been that there is some natural mechanism by which to constrain these values. Inflation does this by forcing the curvature to be very close to flat.

Bzzzzzzzzzz. Thank you for playing.

The horizon problem is nothing to do with fine-tuning. It's an issue with the isotropy of the universe and the transmission of information.

Without invoking inflation, the horizon problem requires an apparent fine-tuning of the initial conditions so that the universe is isotropic without being causally connected. In the standard big bang model, the isotropy across the sky could not be explained by transmission of information. This does not mean that the universe IS actually fine-tuned, it suggests that something is not complete with our model. Inflation solves this problem by having everything in a small enough region to reach equilibrium before inflating.

Err, excuse me, but how does that follow from what I said?

I gave this example because from what I read in your previous post, it seemed you felt that problems of apparent fine-tuning are not actually problems at all, and thus do not need addressing. I was intending to point out that there is useful information to be gained from considering such problems, and what they can tell you about your model.

Now reading your reply, it seems to me that you don't have a problem with apparent fine-tuning, only the claim that something is actually fine-tuned. This is not a claim that I am making, so we would be in agreement. Correct me if I am wrong on this.

Honestly I can't tell if this argument is even meaningful anymore, or if we are just arguing about what apparent fine-tuning implies.

Until such time as fine-tuning is rigorously demonstrated, there is no good reason to suppose it exists.

Suppose what exists? Suppose that certain models are very sensitive to initial conditions? This is a fact that is not in question. The argument here seems to be about what this means. I don't expect to find any evidence of something being actually fine-tuned, because I do not think that anything IS actually fine-tuned, the paper does not make this claim either. Fine-tuning is not a real physical phenomenon. The only claim that I am making here is that the need for a model to have very finely tuned conditions to explain the observations usually suggests that the model is lacking in some way. I believe Andromedaswake points this out in his fine-tuning video as well (although I am at work and only watched it yesterday, so I apologize if I am misrepresenting his point here).

 

[Nelson]

To clarify my position a bit further, I suppose my point boils down to the following. I am promoting the following heuristic idea (although this idea certainly does not originate with me) :

Models that require fine-tuning of certain conditions to match observational data are, in general, poor or incomplete models.

 

[Demojen]

I have an even better idea

Models that require fine-tuning of certain conditions to match observational data are, in general, non-existent.

The only models that require fine-tuning of certain conditions to match observational data are made by matching specific observational data. This is far from general. Observational data must be specific in order to nail down the origins of things in researching Paleontology or Archeology, for instance. We can't just assume the data in-between is an indication of anything when we don't know it.

This is where creationists fail. They assume, and often times allude to arguments from authority in an attempt to undermine peer reviewed researched, tested and scientifically supported evidence.

Science may not know the very beginning, but that's because true science doesn't cut corners and lie.

 

[butterbattle]

I don't think there is sufficient evidence to conclude that this universe is unlikely. But, if we did assume that all the "parameters" universes could be "tuned," it stands to reason that any possible universe is astronomically unlikely. So, no matter what universe we could or couldn't have been in, theists could still make the same fine tuning argument.

The fine tuning argument loses all credibility just on that observation.

 

[borrofburi]

I don't think people are calling you a creationist, nor do I think people are necessarily responding to creationist arguments of fine tuning. Rather I think that in general the flaws people see in this idea and your OP are the same flaws that we see in creationist arguments involving fine tuning, such that it's very difficult to talk about the flaws in one without also making the connection to the other.

 

[Demojen]

You can not make a logical argument of probability when there are no boundaries for the argument.
Probability arguments require by the nature of being based on PROBABILITY, some reference points in a closed system.

An argument of probability referencing infinity is a fallacy.
This is why infinity is not a number. Infinity is an idea.
Probability references numbers, not ideas.

It's as logical as saying "That woman is 53 hot."
53 a number, hot a subjective term(idea) that could reference any number of unspecific arguments. What am I really saying though?
Now replace infinity with a real number and maybe probability arguments could hold a candle...Until then, they can not.