Are Vacuum Fluctuation Models Dead?

07/31/2010 7 comments

In 1973, a new model for the origin of the universe was born when physicist Edward Tryon published a paper (pdf) asking the question, “Is the Universe a Vacuum Fluctuation?”   This model suggests that the universe as a whole is something like a long-lived virtual particle; a random (and extremely large) fluctuation of energy in the quantum vacuum. And although William Lane Craig refers to Tryons proposal as a “bizarre speculation,” it sparked a buzz for the better part of a decade with many physicists proposing different variants on the model (Ex. 1, Ex. 2, Ex. 3).

The problem with all the above models is that they presuppose a background space from which our universe arose. But where did this background space come from? It could have begun in the past – an unsatisfying answer which only pushes back our question of origins another step – or we could say that it is simply eternal. Craig, however, doesn’t like this second answer and raises two objections:

Within any finite interval of time there is a positive probability of such a fluctuation occurring at any point in space. Thus, given infinite past time, universes will eventually be spawned at every point in the primordial vacuum, and, as they expand, they will begin to collide and coalesce with one another. Thus, given infinite past time, we should by now be observing an infinitely old universe, not a relatively young one.

The second objection, that we should be observing an infinitely old universe, seems easily answered by the anthropic principle – an infinitely old universe would have infinite entropy where observers cannot exist. However, the first objection does make sense – given an infinite past of this meta-space, there should be universe-sized fluctuations occurring all over (i.e. our universe should be colliding with other universes, but we don’t see that).

Craig then drives his objections home by quoting physicist Christopher Isham:

According to Isham this problem proved to be “fairly lethal” to Vacuum Fluctuation Models; hence, these models were “jettisoned twenty years ago” and “nothing much” has been done with them since.

The citation for these fragmented quotes points to a 1990 paper by Isham titled  “Space, Time, and Quantum Cosmology,” which I have been completely unable to locate in any book or journal – and according to Google Scholar, this paper has only ever been cited by Craig and various other religious apologists.

Luckily, I was able to find two other papers by Isham which were on the same subject: “Creation of the Universe as a Quantum Process” (1988) published in the book Physics, Philosophy, and Theology and “Quantum Theories of the Creation of the Universe” (1993) published in the book Quantum Cosmology and the Laws of Nature – both of these papers are highly critical of Tryon’s proposal.

. . . Except there is one variation of Tryon’s model which are immune to both Craig’s and Isham’s criticisms: Alexander Vilenkin’s model (pdf). This model, unlike the others, does not propose any sort of background space. Rather, Vilenkin suggests that the universe was a quantum tunneling event “from nothing” – though not “absolutely nothing” (this will be discussed further in a future post).  In fact, Isham writes in his 1993 paper that, “a scheme like Vilenkin’s might have some approximate validity.” Although, Isham cautiously goes on to say that we won’t know for sure until the theories of quantum mechanics and general relativity are unified.

So, are vacuum fluctuation models dead? Well, Tryon’s model  has some serious problems – there’s no doubt about it.  On the other hand, Vilenkin’s variation on Tryon’s theme is still alive and kicking.

On a final note, I’d like to quote a bit of Isham’s 1993 paper (page 50) which seems relevant to this discussion (though you’ll never see Craig using it):

A variety of reactions is generated by the idea that the universe may be temporally finite . . . For example, a rather naive reaction is to posit a God who performs creation at the precise point where the theory breaks down but who is such that the subsequent development of the universe is described exactly by the existing theoretical structure.  The invocation of such a Deistic creator is psychologically understandable even if it cannot be justified logically.

Advertisements
Categories: Cosmic Origins

Bad Advice for Informal Debates

07/22/2010 5 comments

I was reading William Lane Craig’s Q&A post #170 in which the question was, in a nutshell, How can I successfully debate my non-believing co-workers – who claim that Christianity is stupid – when I don’t have enough time to study apologetics?

Here is the first part of Craig’s answer:

One easy thing that we can all do is learn to ask questions. Greg Koukl recommends asking two questions of non-believers:

1. What do you mean by that?

2. What reasons do you have to think that?

It’s amazing how these two disarmingly simple questions can tie people in knots!

Yikes! I thought the first piece of advice would be don’t debate religion with your co-workers. Seriously, you don’t want to be alienated at work (especially if you need the money). So, unless you know your co-workers well enough, either ignore the discussion going on about religion or ask them politely to leave you out of the conversation.

And since the questioner stated that he didn’t know much about Christian apologetics or philosophy (and he is too busy to study it), I thought the second piece of advice would be don’t debate religion if you don’t know what you’re talking about. This goes for theists and atheists alike. If the person you’re debating does know what they’re talking about, then chances are quite high that you’ll look stupid (and this guy’s goal was to show that Christianity is not stupid).

Furthermore, the two questions Craig suggests asking are not very hard to answer.  For example, a person might quote the well-known meme, “Christianity is the belief that a cosmic Jewish zombie who was his own father can make you live forever if you symbolically eat his flesh and telepathically tell him you accept him as your master.”  That certainly does paint Christianity in a fairly silly light.

…Of course, I’m not advocating that people use this sort of argument. It’d probably be extremely unproductive, but it pales in comparison to Craig’s further advice; throw them off on a book, appeal to authority, and then strawman (to be fair, Craig never uses those words but it’s definitely what he describes).

His final piece of advice is the only genuinely good one:  study up on the atheist-theist debate. …Well, actually, Craig suggests that he “memorize the premisses [sic] of the theistic arguments so that you can share them at the drop of a hat.”  But let’s give him the benefit of the doubt.

Categories: Debate

Can a Singularity Be Described as “Nothing?”

07/17/2010 12 comments

According to the Standard Big Bang model, the universe began in the form of a singularity – a point of infinite density and infinitesimal (zero) volume. And although there are problems with extrapolating the Standard model this far back, William Lane Craig seems willing to ignore them so that he can continue claiming that the universe came “from nothing and by nothing.”

But how does the Standard model allow him to make this claim? Well, a singularity’s property of  having “zero volume” is pretty easy to square away with the idea of “nothing,” but as for the singularity’s “infinite density,” Craig has a completely different explanation:

This event that marked the beginning of the universe becomes all the more amazing when one reflects on the fact that a state of “infinite density” is synonymous to “nothing.” There can be no object that possesses infinite density, for if it had any size at all it could still be even more dense.

– W.L. Craig, “The Existence of God and the Beginning of the Universe” (first published 1991; updated 2002).

If  you’re finding yourself thinking, “…uh …what!?” after reading that then you’re not alone.  This is an extremely sloppy piece of work, and it’s hard to imagine that Craig, a man with two PhDs, could have seriously written such a thing. Here are three problems with this argument:

#1: Craig writes, “…if [the singularity] had any size at all…” but the singularity predicted by the Standard model doesn’t have any size at all. So to put it bluntly, this means that Craig’s justification doesn’t even apply to the proper situation.

#2: Craig writes “There can be no object that possesses infinite density,” but the singularity is defined as a state of infinite density. So, even if his justification for this claim made sense, all it proves is that singularities, as they are defined by physics and mathematics, cannot exist. And because the Standard model predicts this singularity, it only means that the standard model is incorrect in this regard (which is probably true).

#3: Craig is claiming that “‘infinite density’ is synonymous with ‘nothing,”” but he only attempts to demonstrate that a state of “infinite density” is impossible. It simply doesn’t follow. As the philosopher Wes Morriston pointed out,

No one would suppose that it follows from the fact that there can be no round squares, that “round square” is synonymous with “nothing.” But neither should anyone suppose it follows from the fact (assuming it is a fact) that there can be no infinitely dense objects, that “infinite density” is synonymous with “nothing.”

To compound the confusion, Craig goes on to quote Fred Hoyle saying that the universe, according to the Standard Big Bang model, was shrunk down to “nothing at all.”  But as I’ve elaborated upon in a previous post, Hoyle was only talking in terms of volume – he didn’t even mention density.

Furthermore, in the glossary to The Inflationary Universe (amazon), theoretical physicist Alan Guth notes that a singularity should also have an infinite pressure and an infinite temperature.  How does Craig explain these properties as being “synonymous with nothing?”  As far as I’ve looked, he never does, but I can assume that his explanation would be as ridiculous as the one he gives for infinite density.

Borde, Guth, and Vilenkin’s Past-Finite Universe

07/14/2010 67 comments

Whenever William Lane Craig is forced to retreat from his use of the Standard Big Bang model, he will often cite a paper by Arvind Borde, Alan Guth, and Alexander Vilenkin:

…three leading cosmologists, Arvin Borde, Alan Guth, and Alexander Vilenkin, were able to prove that any universe which has, on average, been expanding throughout its history cannot be infinite in the past but must have a past space-time boundary.

-W.L Craig “Contemporary Cosmology and the Beginning of the Universe”

The 2003 Borde-Guth-Vilenkin paper (pdf) shows that “almost all” inflationary models of the universe (as opposed to Dr. Craig’s “any universe”) will reach a boundary in the past – meaning our universe probably doesn’t exist infinitely into the past.

Dr. Craig seems to interpret this information as “the universe definitely began to exist” although that is a bit presumptuous. For example, this theorem doesn’t rule out Stephen Hawking’s no-boundary proposal which states that time may be finite without any real boundary (just like a sphere is finite in surface area while it has no “beginning”).

Furthermore, the author of the Arizona Atheist blog asked Vilenkin if his theorem with Guth and Borde proves that the universe had a beginning, and Vilenkin responded:

[I]f someone asks me whether or not the theorem I proved with Borde and Guth implies that the universe had a beginning, I would say that the short answer is “yes”. If you are willing to get into subtleties, then the answer is “No, but…” So, there are ways to get around having a beginning, but then you are forced to have something nearly as special as a beginning.

However, Craig’s main problem is that a beginning of the universe can still be described in scientific terms. Nothing in the Borde-Guth-Vilenkin paper suggests a beginning from “absolute nothingness” (as Craig often claims). In fact, the opposite is true. The authors write,

What can lie beyond the boundary? Several possibilities have been discussed, one being that the boundary of the inflating region corresponds to the beginning of the Universe in a quantum nucleation event.

This “quantum nucleation event” refers to a paper Vilenkin wrote in 1982 (pdf) which discusses the universe coming into being through quantum mechanics. Interestingly, many theists use Vilenkin’s paper as evidence that the universe came from “literally nothing” but Craig has already criticized this work.

Oddly, I’ve been unable to find any article of Craig’s (scholarly or otherwise) which actually quotes from the 2003 Borde-Guth-Vilenkin paper. Instead he almost exclusively quotes a paragraph from Vilenkin’s 2006 book Many Worlds in One (amazon) which discusses the 2003 paper:

It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape, they have to face the problem of a cosmic beginning (pg. 176).

Now that’s a pretty straight forward quote which at least seems to favor Craig’s argument, but on the very same page Vilenkin writes,

Theologians have often welcomed any evidence for the beginning of the universe, regarding it as evidence for the existence of God … So what do we make of a proof that the beginning is unavoidable? Is it a proof of the existence of God? This view would be far too simplistic. Anyone who attempts to understand the origin of the universe should be prepared to address its logical paradoxes. In this regard, the theorem that I proved with my colleagues does not give much of an advantage to the theologian over the scientist.

Vilenkin then concludes this statement by suggesting that cosmic origins could be described in “purely scientific terms” – a task which he attempts in the chapter which follows.

Can the Standard Big Bang Model Describe the Origin of the Universe?

07/09/2010 8 comments

William Lane Craig commonly uses four quotes (Kenny, Davies, Barrow/Tipler, Hoyle) to lend support to his claim that the beginning of the universe came from “nothing,” and all four describe what is called the “Standard” Big Bang model (that is, if they describe a model at all). But what is the standard model?

David Harrison (physics department at the University of Toronto) gives a brief explanation:

There was a big bang some 15 billion years ago, when the size of the universe was zero and the temperature was infinite. The universe then started expanding at near light speed.

According to this model, the universe began as a state of infinite density, infinite temperature, and zero size which is often referred to as a singularity – the “zero size” is why it is often described it as “nothing” (whether or not a singularity is “nothing” will be explained in a later post). At first glance, these properties are  mathematically incoherent; just try plugging zero and infinity in any density equation, and you can get all sorts of nonsense.  But Roger Penrose and Stephen Hawking later solved these problems which temporarily saved the standard model … that is until Hawking realized his mistake:

It is perhaps ironic that, having changed my mind, I am now trying to convince other physicists that there was in fact no singularity at the beginning of the universe—as we shall see later, it can disappear once quantum effects are taken into account

A Brief History of Time (1988), page 50

Of course, quantum mechanics isn’t the only problem which plagues the standard Big Bang Model. Harrison points out three more:

  • The flatness problem: Why is the matter density of the universe so close to the unstable critical value between perpetual expansion and recollapse into a Big Crunch?
  • The horizon problem: Why does the universe look the same in all directions when it arises out of causally disconnected regions? This problem is most acute for the very smooth cosmic microwave background radiation.
  • The dark matter problem: Of what stuff is the Universe predominantly made? Analysis of the gravitational interactions of galaxies shows much more matter than we can see. Nucleosynthesis calculations suggest that this dark matter of the Universe does not consist of ordinary matter – neutrons and protons?

And he continues by stating that “the list is slated to grow” (he wrote this back in 2001, mind you). Even Dr. Craig admits the problem with the standard model:

The standard Big Bang model needs to be modified in various ways. For example, the model is based on Einstein’s General Theory of Relativity. But Einstein’s theory breaks down when space is shrunk down to sub-atomic proportions. We’ll need to introduce quantum physics at that point, and no one is sure how this is to be done.

Dr. Craig goes on to say that “none of these adjustments need affect the fundamental prediction of the standard model of the absolute beginning of the universe” but this is irrelevant.  If Dr. Craig wants to continue making the claim that the universe came from “nothing” then he should stop using the standard model. A model which, according to Harrison, hasn’t been well-accepted since the early 1990s.

As theoretical physicist/cosmologist Alan Guth writes in the preface of his 1997 book The Inflationary Universe (amazon),

The traditional big bang theory has become widely accepted because, as far as we can tell, it gives an accurate picture of how our universe has evolved . . . However, although the standard big bang theory is very successful, there is good reason to believe it is incomplete.

WLC Quotes Fred Hoyle

06/29/2010 6 comments

If there’s one thing that William Lane Craig loves, it’s an appeal to outdated or irrelevant authorities.  So it’s no surprise that Dr. Craig uses Fred Hoyle to promote a specific interpretation of the Big Bang Theory.

Therefore, as the Cambridge astronomer Fred Hoyle points out, the Big Bang Theory requires the creation of the universe from nothing. This is because if you go back in time, you reach a point, at which, in Hoyle’s words, “the universe was shrunk down to nothing at all.”

– William Lane Craig’s opening statement during his debate with Doug Jesseph (1996)

Fred Hoyle was certainly an amazing cosmologist, but he had one major flaw: he was dogmatically opposed to the Big Bang theory until the day he died in 2001. As physicist Ethan Siegel points out on his blog:

The real tragedy is that this brilliant man [Hoyle] simply couldn’t accept new evidence [of the Big Bang Theory] and adjust his world-view accordingly. And so he died in ignorance, clutching onto his discredited theory [the Steady State model], in futility, for nearly the last forty years of his life.

Of course, this doesn’t automatically mean that Dr. Craig’s use of Hoyle is dishonest or incorrect, it’s just a bit sneaky and suspicious.  To get to the heart of the matter we need to look at the source, which turns out to be a textbook Fred Hoyle authored and published in 1975 titled Astronomy and Cosmology. Here is a wider context to the quote (page 658):

Note: the passage refers to a hypothetical triangle where each point represents a galaxy – as time increases the galaxies get further apart.

In the past the triangle was smaller than it is now. In the future the triangle will be larger than it is now. This prompts the question: If we go far enough back into the past, was the triangle ever shrunk down to nothing at all, as in Figure 16.2 [described in above note]? The answer to this is yes, because Q [the scale] was once zero.

The next question is, does the universe actually behave like this hypothetical triangle? The answer to this is no, because this hypothetical scenario only takes area into consideration. Sure, as you shrink a triangle, it will eventually become a single point containing no area. But if we’re talking about galaxies which contain mass, then the density of that point becomes infinite (as does the temperature). Is a point of infinite density (i.e. a singularity) really nothing?  Well, it turns out not to even matter because (quoting physicist Ethan Seigal again) there probably was no singularity:

…the idea that our Universe started from a singularity was a very good one back when we thought that the only important things in our Universe were matter and radiation, but now that we know about inflation, there is no reason to believe that our Universe ever had a singularity in the past.

Of course, the Hoyle’s textbook was written in 1975 which was five years before inflation was proposed, so we shouldn’t really blame Hoyle. However, we can blame William Lane Craig for using a quote that is extremely out of date.

BONUS DEBUNKING

Here is another quote Dr. Craig uses every once in awhile from Fred Hoyle:

A common sense interpretation of the facts suggests that a super intellect has monkeyed with physics.

-As used in W.L. Craig’s article on the problem of evil.

This quote comes from a 1981 article titled The Universe: Past and Present Reflections by Hoyle. Interestingly, Craig cuts off the end of the quote which says “…as well as chemistry and biology, and that there are no blind forces worth speaking about in nature.”  But it doesn’t really matter, the article is nearly 30 years old and blah blah blah.

…It might just be easier to conclude with a remark Dr. Craig made during his debate (a little more than half-way through) with Keith Parsons concerning the idea of “common sense.”

We really disagree on this idea that extraordinary claims require extraordinary evidence, and look what he said in his last speech, ‘it’s just common sense.’  Boy, your anntenna should go up immediately when somebody makes that kind of appeal because that means there’s a want of an argument.

Ask an Astrophysicist on the Origin of the Universe

06/21/2010 5 comments

NASA has a pretty cool feature called Ask an Astrophysicist in which you can ask a question to an astrophysicist.  (duh!)

Well, about a month ago I asked the following question:

In various pop-science books and TV documentaries, astronomers and physicists sometimes refer to the universe expanding from ‘nothing.’  But what exactly do they mean by ‘nothing?’ Does that mean no matter, no energy, no space, no time, no physical laws, no vacuum, etc?

And this was the answer I received:

No one knows.  Our understanding of physics does not extend this far. From a short time after the Big Bang until now, the broad history of the universe is becoming pretty well understood (though with big mysteries like dark energy and dark matter and a lot of other fascinating details to be filled in).  But we have no current understanding of the very beginning.

Dr. Randy A. Kimble
JWST I&T Project Scientist

While I think “no current understanding” sounds a bit too absolute (after all, there certainly are a lot of very good ideas in theoretical physics), it really underscores the fact that we really don’t know much about the initial moments of the universe.