Thursday, June 09, 2005

What is Cosmological Fine-Tuning Evidence For?

A favorite argument of ID folks is that cosmological fine-tuning is evidence for the existence of God (or at least some sort of supernatural designer). The argument is essentially this: There are many properties of the universe around us that have to work out just right for intelligent life to be possible. We could consider things like the ratio of the mass of a proton to the mass of an electron, or the relative strengths of the fundamental forces of nature among other examples. Time and again we find that were the values of these constants even slightly different from what they are, then life of any coneivable sort would be impossible. Meanwhile, there is nothing in current cosmological theorizing to suggest that one particular set of constants was pe-ordained by the conditions of the Big Bang. We therefore have a probabilistic conundrum. It is asking too much of chance that sheer dumb luck could have led our universe to arrive at just the right collection of constants to make life possible. The most plausible explanation, therefore, is that an intelligent designer is lurking behind the properties of the universe as we see them.

I believe this argument is very weak. For the purposes of this blog entry, however, I will focus on just one aspect of it.

Even supporters of this argument concede that if it were shown that ours is just one of an essentially infinite collection of universes, then the probability problem goes away. The idea ia that unlikely outcomes become likely if you repeat the experiment enough times. One supporter of cosmological ID, David Heddle, expresses the issue this way:


I am in the cosmological ID camp. As you are probably aware, cosmological ID theory is based on two observations about our universe: its fine tuning and its uniqueness. Take either support beam away, and the cosmological ID house falls down.

If there is no fine tuning, then there is no evidence for design.

If our universe is not unique, i.e., if we are but one of perhaps an infinite number of parallel universes, then one can logically posit that our particular universe is fine-tuned only because if it were not, we wouldn't be here to talk about it. The multitude of universes, those that are not fine tuned, being sterile, contain no intelligence pondering why they exist in an ordinary, run of the mill cosmos.


So the question is this: Let us assume that we have three options for explaining the apparent fine tuning of the fundamental constants:


  1. Fine-tuning is an illusion. Things appear to be fine-tuned only because we have an imperfect understanding of all of the natural laws of the universe. Were our understanding better than it is we would realize that the values of the constants were sharply constrained by natural laws, or that quantities whose values appear to be independent of one another are actually related.

  2. Our universe is only one of a large number of universes, thereby making it rather easy to explain the fine-tuning of our own universe.

  3. The universe is the product of a supernatural intelligence that deliberately adjusted the constants to make things hospitable for life.


Which of these three explanations is the most likely?

I would argue that either of the first two possibilities is more likely than the third. Let me begin with two historical analogies.

By the nineteenth century Newton's theory of gravitation had been applied with great success to the problem of predicting the trajectories of the planets. But then it was noticed that the orbit of Uranus, then the most distant known planet, differed measurably from what Newton's laws said it should be. To explain this, some scientists of the time suggested that Newton's laws simply didn't hold as widely as was previously thought. Perhaps for planet-size bodies separated by vast distances we needed some different law to guide us. This is rather like argument one above.

Another explanation was that the odd orbit of Uranus was evidence that there was another planet beyond Uranus. Of course, with the discovery of Neptune this turned out to be the correct explanation.

As far as I know, nobody suggested that the anomalous orbit of Uranus was evidence for the intervention of a supernatural entity. Given the other options, would anyone at that time, or ours, have considered that to be the most plausible explanation?

Now for the second example. In the nineteen twenties various experiments revealed what appeared to be a violation of the principle of energy conservation at the atomic level. To explain this, many scientists of the time suggested that energy conservation simply didn't hold at the atomic level. In other words, our understanding of the natural laws of the world was imperfect.

An alternative explanation was that the apparent violation of energy conservation was actually evidence for a previously undiscovered particle. The energy of this particle would account for the apparently missing energy revealed by the experiments. Many scientists of the time regarded this as a ridiculous ad hoc hypothesis concocted merely to preserve energy conservation, but with the subseqeunt discovery of the neutrino it turned out to be correct.

Again, as far as I know nobody suggested supernatural intervention as the most plausible explanation for the missing energy.

Let's return now to the fine-tuning argument, and consider what case can be made for each of the three options I listed above.

It is almost a sure thing that our current understanding of the laws of physics is terribly imperfect. This applies all the more strongly to our understanding of the earliest moments of the universe, where the data we have to work with is minimal indeed. Since the history of science shows that nature seems to have almost limitless resources for surprising us, simple humility makes option one seem pretty plausible.

What about option two? Well, multiple universes are a logical consequence of current mainstream thinking in cosmology. As William Jeffreys put it in in his recent review of the pro-ID book The Privileged Planet, by Gonzalez and Richards:


Gonzalez and Richards's “refutation” of the MWH [Many Worlds Hypothesis] is unconvincing. It consists of a bland dismissal that an actual infinite set can exist (p 268 -- where did they learn their mathematics?) together with a claim that “we have no evidence to think that other universes exist,” a claim that happens to be false, for several reasons. One reason is that it is a prediction of the best-supported theory in cosmology, one that is strongly supported by evidence. And the second is that under that model, our own existence evidentially supports the MWH (since under that hypothesis a selection effect is involved: we can only exist in one of the very small proportion of worlds in which “the constants are right,” so our own existence implies the existence of these other worlds).

As Mark Perakh (2004) has pointed out in another context, there is nothing particularly unparsimonious about the multiverse hypothesis. For one thing, it is based on the observational fact that our own universe definitely exists, and since it does exist, it is reasonable to presume that naturalistic processes would produce other universes, just as different versions of our own. If physics can produce one universe, there is nothing in principle to prevent it from producing infinitely many. Indeed, it would be expected. By contrast, the hypothesis of an intelligent designer of universes is completely speculative; there is, as Perakh points out, not a single observational fact that points to the existence of such an entity other than ancient, conflicting legends.


Jeffrey's hits an important point here. The MWH is not an ad hoc hypothesis designed to circumvent the anthropic principle. It is something physicists have been discussing since at least the nineteen fifties, and follows from other well-supported theories of physics.

It's also a bit rich for ID folks to protest that these multiple universes can not be detected empirically. Their preferred explanation suffers from the same defect, after all. As far as I know they have never produced any evidence that God exists. And if they are inclined to say the fine-tuning itself is evidence that God exists, I reply simply that actually fine-tuning is evidence that multiple universes exist. Hence the title of this blog entry.

So option two receives support from current cosmological thinking, and does not require that we hypothesize into existence something fundamentally new. What about option three? Here there is no case to be made at all.

In fact, if we look at the products of intelligent causes that we see all around us, we would have to conclude that altering fundamental constants and bringing worlds into being are things far, far beyond anything intelligence is capable of. As far as we know (the existence of God is something we're trying to prove here, not something we are assuming), human beings possess the highest level of intelligence in the universe. But we can't do anything close to what the intelligence in ID apparently did. So we are simply making something up out of whole cloth. It is not a simple extrapolation from known examples of intelligent causation.

I don't believe anyone would choose option three as the most likely one unless they already had emotional reasons for wanting to believe in God already.

In this blog entry, David Heddle offers the following thoughts about the MWH. He is responding to the Jeffreys quote I provided above:


Jefferys is engaged in some Clinton-speak here. It is true that we have evidence to think (i.e., speculate) that other universes exist. However, we have no actual evidence that they do. No parallel universe has ever been detected, period. The fact that some current theories are consistent with parallel universe does allow one to think about them, but it is not to be confused with evidence that they exist. Theories are famous for incorrect predictions upon extension. Maybe Jefferys believes that highly successful classical electricity and magnetism is evidence for the fact that electrons will radiate and spiral into the nucleus (which is what it predicts.) He then goes on to argue that assuming the multiverse hypothesis is correct, once again disingenuously implying that actual evidence exists (this “evidence”, permit me to repeat, being that multiple universes is a prediction—and he conveniently neglects to mention that it is an untestable prediction) then, surprise surprise, Gonzalez and Richards are wrong. Woulda-coulda argument, Mr. Jefferys.


When an ID person gets that smug, it's a sure sign that he's making a really bad argument.



  • I can think about the possibility of multiple universes without any physical evidence at all, thank you very much. After all, ID folks routinely think about God's wishes and desires without a shred of direct evidence for God's existence.

  • If a well-supported theory has as a consequence that entity X exists, that constitutes actual evidence that X exists. It's not conclusive proof that X exists. It is not the best sort of evidence you can possibly imagine for the proposition that X exists. But it is important evidence nonetheless.

    We saw that in the historical examples above. We had good evidence for the existence of Neptune on the one hand, and the neutrino on the other, simply on the grounds that their existence would allow us to preserve other well-established physical theories (Newton's laws on the one hand, energy conservation on the other). To believe otherwise is to believe that the scientists who used that sort of reasoning to look for the planet Neptune, or to find physical traces of the neutrino's presence, were behaving irrationally.

    And the fact that the MWH is supported by current theories in cosmology is certainly better evidence than what can be produced for the eixstene of God, which is Heddle's preferred explanation.

  • I'm afraid I can't find anything disingenuous in Jeffreys' review.

    He quotes Gonzalez and Richards as claiming that we have no reason to believe that multiple worlds exists. In reply Jeffreys points out that we do have reasons for so believing. Seems clear enough.

    And he does not argue that Gonzalez and Richards are wrong by assuming the MWH is right. He argues simply that the plausibility of the MWH in light of the reasons he provides shows that Gonzalez and Richards are wrong to pick the supernatural option as the most likely explanation for fine-tuning. I'm not sure what Heddle finds so complicated about that.

  • Heddle wants us to believe that scientists are making unreasonable extrapolations when they say that current cosmological theories imply the reality of the MWH. That's possible, but if it is true it would simply play into option one. It would suggest that we still have an awful lot to learn about the origins of the universe.


The reasoning that leads from “The universe is fine-tuned for life,” to “God exists!” rests on a mountain of unsupported, and probably false, assumptions. You may as well simply assume that God exists and be done with it.

20 Comments:

At 7:31 PM, Anonymous Anonymous said...

I have not read the Gonzales/Richards book, but I suspect that their rejection of an actual infinite is not a rejection of an actual infinite as a number, but rather, whether an actual infinite number of things can exist in reality. For example, could there exist an actual infinite number of universes?

One of the problems with the criticisms against GR--"where did they learn their mathematics"--is that it's not a matter of mathematics qua mathematics; it's a matter of ontology: Can an infinite number of things actually exist?

Someone may counter this by saying that between any two points there is an infinite number of points. But this, pardon the point, misses the point. The "infinite number" of points between, let's say X____Y, are not an actual infinite, since if I traverse X to Y I have not traversed an actual infinite number of points, but a finite distance between X and Y. But could I traverse X to Y, but crossing half way each time (i.e., Xeno's paradox)? Of course not, since I would never in principle reach Y no matter how many times a divide each traversing move in half.

To provide another example, suppose that X and Y were in fact an infinite distance apart? Could one reach Y when beginning from X? No. In fact, it's not possible, since no matter where one stops in one's journey one still has an infinite number of points to traverse. If, let's say, someone suggests that our present universe is the result of an infinite number of predecessor universes, then an absurdity arises: in order to arrive at the present universe, existence must be passed on through an infinite number of points. But we know we cannot traverse an infinite number. So, there cannot be an infinite number of universes.

Suppose someone suggests that there could be an infinite number of parrellel universes that exist simultaneously. But this is absurd as well, for it would mean that if there were half as many universes as there are right now, there would still be an infinite. And if we added one more, there would still be an infinite. In fact, we could divide the universes in half every day for a zillion years, and we'd still have an infinite number of universes left over.

Suppose, however, there are just lots of parallel universes, and not an infinite number of them. Here, new problems arise, for either there has always been multiple universe or there has not. If the former, then there have been an infinite number of moments in all the multiple universes. But we already know that that is impossible. On the other hand, if the multiple universes began to exist at some finite point in the past, then First Cause arguments come into play, and metaphysics kicks in.

Jason, you raise good points, but I think you are giving the GR short shrift.

 
At 8:24 PM, Anonymous J. J. Ramsey said...

You missed a fourth option:

4. There is only one universe, and it looks fine-tuned to us because if it didn't, we wouldn't be around to notice the lack of "fine-tuning."

 
At 10:55 PM, Anonymous Anonymous said...

'where did they learn their mathematics?"

A review of the last year of Panda's Thumb is all anybody needs to know about David Heddle. He essentially tries to argue that a result is extremely improbable, without any knowledge whatsoever about the distribution of possible results. He argues that the desired interval (in the mks system, btw) is so small one can assume unlikeliness. This is a freshman statistics error, motivated by religion.

-steve
(one of several people who tried to explain the problem to him)

 
At 11:26 PM, Anonymous HRG said...

Re actual infinite: Xenon's argument - which anonym essentially uses - is defeated by calculus: specifically the fact that infinite sums have a finite value.
Thus if I take 1 minute to pass the first half of the distance between X and Y, 1/2 minute to pass the first half of the remaining distance, etc., after 2 minutes I will be at X, although I have passed infinitely many steps.

I'm afraid that philosophical notions of ontology are not binding on reality.

Regards, HRG.

 
At 12:25 AM, Anonymous Anonymous said...

This is a very well-reasoned rebuttal. I agree with most of what you said... but not all.

A theory making a prediction about something is not *at all* evidence for its existence. It is simply an extrapolation.

Evidence is observation. Evidence is data, not prediction. The neutrino was predicted to exist because of an observed symmetry imbalance. Neptune was predicted to exist because of an observed orbital perturbation on Uranus.

But that was actual evidence; an observation that led to the prediction of something unseen. No such observation of multiple universes yet exists. None. There is room in the theory for it, but there is also room for God. Neither multiple universes nor God is *precluded* by theory.

HOWEVER, that is different than predicting God. There are indeed theories that predict multiple universes; membrane theory is one of them. I have heard that 'branes also make testable predictions involving the size and shape of gravity waves from the early Universe, which is an interesting addendum to this argument, and one I intend to pursue sometime. But either way, no theory I know of predicts God. Scientifically, this makes that a supposition even more removed than MWH.

Certainly, a prediction by a theory, especially one with many successful prior predictions, is cause to look for evidence, but that prediction is not evidence in itself.

And as far as fine-tuning goes, in the book "Why Intelligent Design Fails", Victor Stenger makes a case that the Universe is not all that fine-tuned; change a few things and some version of life could still be possible. This is another avenue I intend to pursue.

Don't get me wrong: I will chase down the nonsense of creationism the best that I can. But we have to be careful that we are *absolutely as correct as we can be* when we do. Any failure, even a perceived one, no matter how small, will be trumpeted by creationists.

-Phil Plait
The Bad Astronomer
http://www.badastronomy.com/bablog

 
At 5:00 AM, Anonymous David Heddle said...

Steve,

It is impossible to characterize your distortions of my arguments any other way: you are a liar. I understand that people always bias what opponents have said in order to make themselves look better, but I believe you are different: you are so insecure that you make a straightforward decision to lie.

Fine tuning is related to improbability, even with no prior knowledge of distributions.

So your argument is this: you cannot claim something, say the cosmological constant, is fine-tuned if you have no knowledge of the a priori distributions.

Yet you never claim that all the non ID cosmologists who acknowledge fine tuning are making a freshman statistics error. Why is that?

Then when I have tried to give pedagogical examples, you do something completely disingenuous: you dig them out and claim they are my proof, not illustrations, or that my proof depends on the mks system, because I (guess) I used an example from the mks system.

Being wrong is no disgrace to a scientist, but being a liar, which is what you are, is.

j. j.,

Your proposal, as I understand it, is not acceptable to anyone: one universe, actual, inexplicable fine tuning, no ID.

The only way non IDers can accept a single universe is if the fine tuning is only an illusion.

While it is true that we wouldn't be here if the universe were not habitable, no non-IDer accepts that one and only one universe is truly fine-tuned, shrugs, and moves on.

Bad Astronomer

I agree: prediction is never a form of evidence. In science, detection and only detection constitutes evidence.

For crying out loud, the mundane aspects (if they can be called that) of M-brane theory have yet to be tested--how can the fact that it predicts parallel universes be called evidence?

But even if other aspects are tested and verified, its prediction of multiple universes will remain, just a prediction. The prediction would be more plausible, but it is not evidence.

 
At 5:01 PM, Anonymous Anonymous said...

Heddle writes:
"you never claim that all the non ID cosmologists who acknowledge fine tuning are making a freshman statistics error. Why is that?"

What cosmologists "acknowledge" is mere *apparent* fine tuning only given their *acknowledged* unsupported assumption that all values are equally probable and/or no MW. If they employed your above flat "We acknowledge fine-tuning!" without constantly adding the qualifiers, they would be encouraging any math-illiterate readers eager for apologetics to commit a freshman statistics error.

 
At 5:13 PM, Anonymous David Heddle said...

Ooh anonymous you caught me!!

Everyone of these quotes (ref. upon reques), from mostly non-IDers:

Arno Penzias, who shared the Nobel Prize for the “discovery of the century”, the 2.7K cosmic background radiation:

Astronomy leads us to a unique event, a universe which was created out of nothing, one with the very delicate balance needed to provide exactly the conditions required to permit life, and one which has an underlying (one might say “supernatural”) plan.

Chinese astrophysicist Fang Li Zhi, and coauthor Li Shu Xian:

A question that has always been considered a topic of metaphysics or theology has now become an area of active research in physics.

George Ellis, colleague of Stephen Hawking and mathematician Roger Penrose:

Amazing fine-tuning occurs in the laws that make this [complexity] possible. Realization of the complexity of what is accomplished makes it very difficult not to use the word “miraculous” without taking a stand as to the ontological status of that word.

Stephen Hawking:

It would be very difficult to explain why the universe should have begun in just this way, except as an act of a God who intended to create beings like us.

Cosmologist Bernard Carr:

One would have to conclude that either the features of the universe invoked in support of the Anthropic Principle are only coincidence or that the universe was indeed tailor made for life. I will leave it to the theologians to ascertain the identity of the tailor.

Astronomer George Greenstein:

As we survey all the evidence, the thought instantly arises that some supernatural agency—or rather Agency—must be involved. Is it possible that suddenly, without intending to, we have stumbled upon scientific proof of the existence of a Supreme Being? Was it God who stepped in and so providentially crafted the cosmos for our benefit?

Astronomer Fred Hoyle, staunch anti-theist:

A superintellect has monkeyed with the physics, as well as the chemistry and biology.

Tony Rothman, theoretical physicist:

The medieval theologian who gazed at the night sky through the eyes of Aristotle and saw angels moving the spheres in harmony has become the modern cosmologist who gazes at the same sky through the eyes of Einstein and sees the hand of God not in angels but in the constants of nature… When confronted with the order and beauty of the universe and the strange coincidences of nature, it’s very tempting to take the leap of faith from science into religion. I am sure many physicists want to. I only wish they would admit it.

Cosmologist Edward Harrison:

Here is the cosmological proof of the existence of God. The fine tuning of the universe provides prima facie evidence of deistic design. Take your choice: blind chance that requires multitudes of universes or design that requires only one. Many scientists, when they admit their views, incline to the theological or design argument.

My personal favorite:

Heinemann prize winner Robert Griffiths:

If we need an atheist for a debate, I go to the philosophy department. The physics department isn’t much use.

Robert Jastrow:

For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been waiting there for centuries.

Paul Davies:

[There] is for me powerful evidence that there is something going on behind it all…It seems as though somebody has fine-tuned nature’s numbers to make the Universe…The impression of design is overwhelming.

Lawrence Krauss (on the dark energy problem):

This is the worst fine tuning problem in physics.

is followed, every single one of them, by a qualifier: "assuming a uniform distribution of all possible values!" which I conveniently omit because the first thing you learn in ID boot camp is to quote mine.

 
At 7:50 AM, Anonymous Erik 12345 said...

David Heddle wrote: "... because the first thing you learn in ID boot camp is to quote mine."

Heddle is indeed a quote miner. Concerning the quote from Krauss above, which Heddle still uses, I encourage readers to visit

http://www.pandasthumb.org/pt-archives/000445.html

and scroll down to post #7377, where I explained to Heddle what kind of fine-tuning is being referred to, #7391, where I explained the same thing a bit more, and finally #7393, where I report the answer I got from Krauss when I asked about it. Between and below these posts you will also find protestations by Heddle. In short, Krauss is not talking about the kind of fine-tuning that Heddle presents it as. To misunderstand Krauss' words is human, but to persists in misrepresenting them after being corrected is completely shameless.

 
At 9:07 AM, Anonymous David Heddle said...

Oh yes, honest Eric sent this email to Krauss, who is not an IDer:

Hi Dr. Krauss.

I am arguing with someone about what, exactly, you meant by the phrase “the most extreme fine tuning problem known in physics” in the article

Krauss L.M. (1997) “The End of the Age Problem, And The Case For A
Cosmological Constant Revisited”, preprint astro-ph/9706227,
arxiv.org/abs/astro-ph/9706227

One of us thinks that this refers to the difficulty in formulating a model of the microscopic phenomena that give rise to a cosmological constant with a reasonable value.

That is, the mentioned “fine tuning problem” is a problem concerning the construction of microscopic models in which a cosmological constant arises naturally.

The other one of us thinks that it is an example of the kind of fine tuning that is often used to argue that our universe was consciously created by some supernatural entity. That is, the mentioned “fine tuning problem” is a problem related to the construction/origin of our universe through non-divine means.

So which one of us, if any, is right?

Thanks in advance,
Erik


Didn't stack the deck, just a teeny bit, did you Eric?

To which Krauss responded:

From: “Lawrence Krauss”
To: “Erik”
Sent: Sunday, September 05, 2004 6:32 PM
Subject: Re: Question about your preprint astro-ph/9706227


Hi… I was referring to the difficulty of formulating a microscopic model where the vacuum energy is fine tuned to be 120 orders of magnitude smaller than one might expect it to be. It has nothing to do with any supernatural entity… it is a fundamental physics issue.

LMK


Notice two things. Erik's letter, boiled down to its essence, is: "am I right, or does your statement support supernatural design?" That is how he presented my position. For Krauss to agree with me, he would have to agree with ID, with we already know he does not.

And look at Krauss's answer. He most certainly does NOT affirm Eric’s position (..is a problem concerning the construction of microscopic models in which a cosmological constant arises naturally), but actually states what, if you look at all the posts on that page, is consistent with what I said about Krauss. And then he distances himself from ID.

Typical PT type tactic:

Eric: Hey Krauss, do you agree with me or some ID wingnut?
Krauss: neither
Eric: Victory is mine!

In the whole thread, I did not say that Krauss supported design, I said that he acknowledged fine tuning. And he does. There was no quote mining.

For Krauss’s own words, go here:
http://tinyurl.com/4tfwx

Where is steve--he should write Krauss and ask him how he dares mention fine-tuning without a priori probability distributions.

 
At 10:37 AM, Blogger Neurode said...

If this correspondence has been accurately reproduced, then Heddle is right.

To say that "the fine tuning problem is a problem concerning the construction of microscopic models in which a cosmological constant arises naturally" is to affirm bottom-up (micro to macro) causation. This is confirmed by the suggested alternative, "that our universe was consciously created [from the top down] by some supernatural entity".

Krauss, apparently unable to endorse either alternative, replies by invoking the very term at issue, "fine-tuning". In effect, he merely repeats the question, thereby circumlocuting the nature of the underlying causality. His take on the causation of fine-tuning is thus scientifically and philosophically vapid.

In other words, while Krauss may have demonstrated political smarts in sidestepping the question, political smarts and scientific smarts do not necessarily align. So there is really no reason to ascribe scientific value to his opinion on ID, or for that matter on the physical relevance of "supernatural entities" (as opposed to a high-level naturalistic entity consistent with a proper definition of nature).

Of course, all of this will no doubt be lost on Jason.

 
At 12:34 PM, Anonymous Erik 12345 said...

David Heddle wrote: "Didn't stack the deck, just a teeny bit, did you Eric?"

In what way did I stack the deck?

Krauss is writing the problem that a naive estimate of the cosmological constant based on the assumption that it is the result of vacuum energy gives a value that is off by 120 orders of magnitude. The "fine-tuning" problem in this case concerns how we should move beyond this naive estimate and derive the correct value from fundamental physics models. The fine-tuning problem you speak of concerns the ranges that certain physical parameters, not constrained by known physical principles, must have to allow life - the "problem" part being that many think these ranges are in some sense very small and improbable. You and Krauss are quite obviously not referring to the same kind of "fine-tuning problem" (allowing life vs. predicting the observed value of a parameter). This is blatantly clear from my PT posts and from Krauss' reply.

 
At 2:13 PM, Blogger Neurode said...

I can't answer for David Heddle. But insofar as some brain-dead twit recently accused me of having been "beheddled" on Panda's Thumb, as anti-scientific a duncefest as exists on the web, I'll explain why I personally think you stacked the deck.

1. "Krauss is writing [about] the problem that a naive estimate of the cosmological constant based on the assumption that it is the result of vacuum energy gives a value that is off by 120 orders of magnitude. The fine-tuning problem in this case concerns how we should move beyond this naive estimate and derive the correct value from fundamental physics models."

Yes, but from models which apply on all scales, not merely the microscopic scale. As I mentioned, that kind of restriction amounts to an implicit endorsement of bottom-up cosmology, particularly since lambda is a globally-distributed quantity. That is, when one inquires regarding the causal relationship between a set of microscopic criteria "at the bottom" and a global parameter like lambda (or for that matter the vacuum energy) "at the top" of a relational hierarchy, one should refrain from dichotomizing between pure bottom-up causation and "the intervention of a supernatural entity". To do so is to stack the deck by limiting the number of possible explanations and excluding possible naturalistic explanatory models incorporating top-down causation, i.e. top-down models based on a reasonable definition of "nature".

2. "The fine-tuning problem you speak of concerns the ranges that certain physical parameters, not constrained by known physical principles, must have to allow life - the "problem" part being that many think these ranges are in some sense very small and improbable."

They are small and improbable except under a restrictive assumption of dependency among the parameters of "fundamental physics models", including any model endorsed by Krauss. Such dependencies would need to be stated explicitly, particularly given their possible reliance on metaphysical judgments. Of course, this alone does not rule out the possibility that a purely physical form of "fine-tuning" will ultimately be proven inevitable within the constraints of some fundamental physical model. But that does not make Krauss' fine-tuning problem different from anybody else's fine-tuning problem.

3. "You [Heddle] and Krauss are quite obviously not referring to the same kind of "fine-tuning problem" (allowing life vs. predicting the observed value of a parameter)"

...unless, that is, the parameter in question is critically related to the possibility of life, and thus to observational and predictive processes. I daresay that you and Krauss have not yet demonstrated the nonexistence of such a relationship.

 
At 2:18 PM, Anonymous David Heddle said...

Erik,

You are saying foolish things. For your sake I hope that someone you trust, who is not an IDer, and who knows a little cosmology will set you straight, because I know you won’t believe me. The fine tuning of the cosmological has nothing whatsoever to do with naïve estimates—nothing at all. Not even close. You are missing the boat by so much it doesn’t even give me pleasure to tell you that you are wrong. You could not, in fact, be more wrong. The fine tuning has to do with dark energy and inflation. Look in the cosmological constant section of this ANTI-ID, ANTI-FINE-TUNING paper by PT friend Vector Stenger:

http://tinyurl.com/8j9p7

He gives a decent (though biased) description starting on p. 15. You must realize, I would think, that neither Krauss nor anybody else would make a big deal, let alone call it the “worst fine tuning problem” if it was merely due to a naïve estimate. In fact, the problem exists independent of the value of the cosmological constant, as long as it is not identically zero.

Why not write Krauss again, with your explanation for why you think he used the term fine tuning, saying nothing about ID, and just ask if you understand him correctly.

 
At 3:53 PM, Anonymous Anonymous said...

The IDers are probably shooting themselves in the foot (yet again) by pointing to the vacuum energy "problem". This is one of a long series of things in physics which seem impossible to resolve at first, but then wind up being explained. I point you to, for example, the "ultraviolet catastrophe" of the late 19th century. In general, new science comes along to solve these problems. That's what science *is*.

If someone comes along and explains this "fine tuning" naturally and simply using new physics, what then? Will you find another gap you can claim is unpassable?

ID cannot make claims of its own. All it can do, like the creationism it oh-so-coyly denies being, is point out places where science has not as yet gotten an answer, and claim it must be due to design (well, it can also make false claims about science, too, as we've seen many times).

I suggest IDers look up the term "Zeno's paradox". They are well on their way to a geometrically decreasing series of "gaps" to point at. As science fills 'em in, IDers will have to keep finding smaller one to decry.

-Phil Plait
Bad Astronomy
http://www.badastronomy.com/bablog

 
At 10:15 PM, Blogger Anthony Perez-Miller said...

The reasoning that leads from "The universe is fine-tuned for life," to "God exists!" rests on a mountain of unsupported, and probably false, assumptions. You may as well simply assume that God exists and be done with it.

Every argument ultimately rests upon unsupported assumptions. They're called postulates. Some postulates are more vulnerable to refutation than others; presumably, your motivation in critiquing fine-tuning arguments is to cast aspersions on the postulate of God's existence.

With respect, you've got some work to do.

I'll begin with a quibble. Physicists may well have been "discussing" many-worlds hypotheses for decades, but the only field in which such ideas have ever held real currency is in contemporary cosmology. The many-worlds interpretation of quantum mechanics, for instance--which in sum posits that every possible QM outcome does in fact occur, in some universe--is generally regarded by both physicists and philosophers of science as silly.

Serious cosmological proposals regarding multiverses haven't been around since the 1950s, contrary to your claim:more like two decades, three at the outside. And although such hypotheses might be "mainstream", as you suggest, they certainly have not reached the status of established consensus. (More on this below.)

Second: Arguments from analogy are only as strong as the analogy, and your historical examples fall down on this point. Suppose that our universe is but one member of an infinite ensemble--or, if you prefer, that hyperinflation means that parts of our own universe are forever inaccessible to us. Do the laws of physics work the same in these other universes (or bubbles)? What about pre-singularity physics?

In short, you are analogizing from the physical laws of our local universe to causality in epochs and/or regions to which we have no access in principle. At least when design advocates make analogies between organisms and machines, we can discuss exactly how said analogies break down.

Third: If you though the last sentence was a low blow, I'm not finished comparing the logic of your arguments with those of ID types. To quote:

It is almost a sure thing that our current understanding of the laws of physics is terribly imperfect. This applies all the more strongly to our understanding of the earliest moments of the universe, where the data we have to work with is minimal indeed. Since the history of science shows that nature seems to have almost limitless resources for surprising us, simple humility makes option one seem pretty plausible.

You have clearly assigned a high prior probability to the no-fine-tuning hypothesis. Then you assert that our ignorance renders this hypothesis "pretty plausible". But this reasoning precisely mirrors that of a God-of-the-gaps argument, which assigns a high prior probability to design and then argues that our ignorance of precise mechanism renders design "pretty plausible".

Fourth: If a well-supported theory has as a consequence that entity X exists, that constitutes actual evidence that X exists.

Uh...no. Theoretical predictions are not evidence. They're...predictions, which then must be confirmed by other means. Which, incidentally, is just what occurred in your historical examples. The scientists in were behaving rationally, because they were testing hypotheses.

You also need be careful with "well-supported". Biological evolution is well-supported. Quantum mechanics is well-supported, if annoyingly instrumentalist. Are multiverse hypotheses in cosmology well-supported? Certainly not in the same way. Some might be consistent with what we know about inflation (which still isn't very much). But for the most part, cosmology remains a theorists' playground, and likely will for the forseeable future. Pretty mathematical theories are not evidence, not even in a prima facie sense: the internally consistent is not necessarily true.

Or to put it another way: I don't believe anyone would choose option two as the most likely one unless they already had emotional reasons for wanting to disbelieve in God already.

 
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