Gunnar vs Stephen Hawking

Nei, ekki Gunnar í Krossinum á móti Stephen Hawking. Ég hreinlega veit ekki hvaða Gunnar þetta er en ég vona að hann hafi ekki á móti því að ég veki athygli á þessu. Málið er að vinur minn benti mér á spurningu frá einhverjum Gunnari frá Íslandi til William Lane's Craig sem er vel þekktur kristinn fræðimaður.  Hérna spyr Gunnar góðra spurninga varðandi nýju bók Stephen Hawkings og svar Craigs er mjög fróðlegt. Er samt ósammála Gunnari þegar hann segir að Hawking er einn af merkilegustu vísindamönnum sögunnar, ég myndi frekar segja að hann er með merkilegri vísindamönnum samtímans. 

Hérna er þetta, tekið héðan af http://www.reasonablefaith.org 

Hello Mr. Craig.

I am sure you saw the excerpts from Stephen Hawking's soon to be published book "The Grand Design". There he claims that because of the law of gravity "the universe can and will create itself from nothing". So, according to Hawking, there is no need to refer to God since "spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist."

Now I am no physicist, and I can understand that an auther sometimes needs to go to some length in order to publicize and marketing his book so as to ensure a good sale, but to me this seems to be simply an irrational leap, to say the least.

Although all we have here are a few statements from a book lenght argument, nevertheless all sorts of questions come to mind.

Of course Hawking does not believe that the universe really came from nothing since gravity was there to do the creating. And certainly gravity is not nothing. But what is gravity apart from the universe (i.e. space and mass)? Are the laws of nature not properties of the universe? Are they not part of it? Did they not come into being with the universe? Where did gravity come from?

How is it possible to strech science outside the universe, i.e. the setting of scientific inquiry. How can the scientist jump behind the Big Bang? How can he infer anything scientifically about what came before the Big Bang? In doing so, it seems to me, one has entered into the realm of metaphysics.

And then, of course, there is the absurdity of the self-contradictory notion a la Dennet that the universe (or anything at all) could create it self from nothing.

It seems to me that Hawking simply replaces one transcending cause (God) for another (gravity).

It goes without saying that Stepehn Hawking is one of the greatest scientist in history. Nevertheless I am truly astonished.

Could you give me your perspective on this?

Respectfully,

Gunnar
Iceland

Dr. Craig responds:

We have been inundated with questions about the sensational claims touted in the press in advance of the release of Hawking and Mlodinow’s new book The Grand Design. I chose your question, Gunnar, not merely because it was representative of so many but because I couldn’t resist posting a question from Iceland!

In my blog of September 6, in advance of the book’s release, I posed several questions that we need to keep in mind when we come to the book. Those questions proved to be right on the money. Not only is there nothing of scientific substance new in this book, nothing that Hawking had not already stated in his earlier best-seller A Brief History of Time, but Hawking and Mlodinow also fail to take any cognizance of criticisms in the literature of Hawking’s earlier proposals. If you have digested my treatment of the origin and fine-tuning of the universe in Reasonable Faith, 3rd ed., then you are already equipped to respond to the claims of this new book.

Hawking and Mlodinow seek to answer three questions in this book:

1. Why is there something rather than nothing?

2. Why do we exist?

3. Why this particular set of laws and not some other?

Curiously, their answer to each of these questions turns out to be very brief. In fact, (2) gets folded into (1) and so doesn’t even receive a separate answer.

Hawking and Mlodinow’s answer to questions (1) and (2) is an appeal to the “no boundary” model of the origin of the universe, popularized by Hawking in A Brief History of Time. Our authors simply expound the model without adducing any evidence for it or mentioning any of the alternative models to it. Nor do they respond to the criticism that the so-called “imaginary time” featured in the model is physically unintelligible and therefore merely a mathematical “trick” useful for avoiding the cosmological singularity which appears in classical theories at the beginning of the universe.

Still, their exposition is not without interest with regard to whether the universe had a temporal beginning. They write,

The realization that time can behave like another direction of space means one can get rid of the problem of time having a beginning, in a similar way in which we got rid of the edge of the world. Suppose the beginning of the universe was like the South Pole of the earth, with degrees of latitude playing the role of time. As one moves north, the circles of constant latitude, representing the size of the universe, would expand. The universe would start as a point at the South Pole, but the South Pole is much like any other point. To ask what happened before the beginning of the universe would become a meaningless question, because there is nothing south of the South Pole. In this picture space-time has no boundary—the same laws of nature hold at the South Pole as in other places (pp. 134-5).

This passage is fascinating because it represents a rather different interpretation of imaginary time than what we had in A Brief History of Time. Here the analogy of the South Pole is interpreted to imply a beginning point to both time and the universe. Despite the fact that imaginary time behaves like another spatial dimension, Hawking allows the circles of latitude to play the role of time, which has a beginning point at the South Pole. When Hawking speaks of “the problem of time having a beginning,” what he means is “the age-old objection to the universe having a beginning” (p. 135), an objection which his model removes. That age-old objection is the question, “What happened before the beginning of the universe?” Hawking is right that this question is meaningless on his model; but what he fails to mention is that the question is equally meaningless on the standard big bang model, since there is nothing prior to the initial cosmological singularity. On either model the universe has an absolute temporal beginning—just as the second premiss of the kalam cosmological argument states.

So the question is, why did the universe begin to exist? Why is there something rather than nothing? Hawking and Mlodinow advocate what they call a “top down” approach to this question. The idea here is to begin with our presently observed universe characterized by the standard model of particle physics and then calculate, given the no boundary condition, the probability of the various histories allowed by quantum physics to reach our present state. The most probable history represents the history of our observable universe. Hawking and Mlodinow claim that “in this view, the universe appeared spontaneously from nothing” (p. 136). By “spontaneously” they seem to mean without a cause.

But how does that follow from the model? The top down approach calculates the probability of our observable universe given the no boundary condition. The top down approach doesn’t calculate the probability that the no boundary condition should hold but takes it for granted. Such a condition is not metaphysically or physically necessary. If the universe came into being uncaused from nothing, it could have had any sort of conceivable spatiotemporal configuration. For nothingness, or non-being, has no properties or constraints and is governed by no physical laws. Physics only begins at the “South Pole” in the no boundary model. There isn’t anything in the model that implies that that point came to be without a cause. Indeed, the idea that being could arise without a cause from non-being seems metaphysically absurd.

Hawking and Mlodinow seem to realize that they have not yet answered the question, “Why is there something rather than nothing?,” for they return to this question in their concluding chapter and give a quite different answer. There they explain that there is a constant vacuum energy contained in empty space, and if the universe’s positive energy associated with matter is evenly balanced by the negative energy associated with gravitation, then the universe can spontaneously come into being as a fluctuation of the energy in the vacuum (which, by a clever sleight of hand, they say “we may as well call . . . zero”). This seems to be a very different account of the universe’s origin, for it presupposes the reality of space and the energy in it. So it’s puzzling when Mlodinow and Hawking conclude, “Because there is a law like gravity, the universe can and will create itself from nothing in the manner described in Chapter 6” (p. 180). Here it is said that the nothingness spoken of in Chapter 6 is not really nothingness after all but is space filled with vacuum energy! That goes to reinforce the conviction that the no boundary approach only describes the evolution of our universe from its origin at its “South Pole” to its present state but is silent as to why the universe came to exist in the first place.

What this implies is that Hawking and Mlodinow have not even begun to address the philosophical question, “Why is there something rather than nothing?” For “nothing” in their vocabulary does not have the traditional meaning “non-being” but rather means “the quantum vacuum.” They aren’t even answering the same question. Like the philosophy student who, put the question, “What is Time?” on his final exam, answered, “a weekly news magazine,” so Hawking and Mlodinow have avoided the tough question by equivocation.

If they have thus failed to answer questions (1) and (2), what about (3): Why is there this particular set of laws rather than some other? The issue here is explaining the apparently miraculous fine-tuning of the universe for intelligent life. Hawking and Mlodinow express this idea by observing that “in recent years physicists began asking themselves what the universe would have been like if the laws of nature were different” (p. 159).

Unfortunately, this statement is very misleading. Scientists grappling with fine-tuning are not asking what the universe would have been like if it were governed by different laws of nature. Rather they’re asking what the universe would have been like if it were governed by same laws of nature but with different values for the physical constants appearing in them and with different quantities for the initial conditions on which the laws operate. Nobody knows what a universe governed by different laws would be like! But because we’re talking about universes governed by the same laws, but with different numbers plugged in for the constants and quantities, we can calculate what kind of universe the laws would predict (just as Hawking and Mlodinow illustrate on pp. 159-62). So question (3) is malformed as stated. The real question is: why this particular set of constants and quantities rather than some other?

Now there are three possible answers to that question: physical necessity, chance, or design. Hawking and Mlodinow reject the hypothesis of physical necessity: “It appears that the fundamental numbers, and even the form, of the apparent laws of nature are not demanded by logic or physical principle” (p. 143). Since Mlodinow and Hawking want nothing to do with a Cosmic Designer, they opt for the hypothesis of chance. Since the odds of our universe’s being fine-tuned for intelligent life are so incomprehensibly remote, Hawking and Mlodinow appeal to the Many Worlds Hypothesis to augment one’s probabilistic resources to the extent that it becomes inevitable that a finely tuned universe will appear by chance somewhere in the World Ensemble or multiverse. If there are an infinite number of randomly ordered universes in the Ensemble, then a finely tuned universe will appear somewhere in the Ensemble by chance alone.

Now if the Many Worlds Hypothesis is to be serious science rather than metaphysical speculation, some sort of mechanism needs to be provided to generate the World Ensemble. The mechanism to which Hawking and Mlodinow appeal is Richard Feynman’s “sum-over-histories” approach to quantum theory. This is the approach which Hawking uses in the no boundary model to calculate the most probable history of the universe, given the no boundary condition, to our present observed state. Hawking and Mlodinow take these alternative histories which the universe might have pursued to be actual, parallel universes which are just as real as our universe.

Unfortunately, this is not science but a gratuitous piece of metaphysics. Feynman’s sum-over-histories method is just a mathematical tool for calculating the probability of a subatomic particle’s arriving at one point from another. One imagines all the possible paths the particle could have taken and then on that basis calculates the probability of its reaching the observed destination. There’s no basis for interpreting this mathematical “trick” to imply the ontological reality of concrete, spatio-temporal universes.

Hawking and Mlodinow also appeal to M-Theory or superstring theory to generate the World Ensemble of universes exhibiting various values for the constants of nature. Such a speculation is problematic in a number of ways which they do not discuss. First, the “cosmic landscape” of 10500 different possible universes consistent with nature’s laws which M-Theory allows are just that: possibilities. They are not real worlds, anymore than are Feynman’s histories. Second, it’s not clear that 10500 possibilities are sufficient to guarantee the existence of finely tuned universes in the landscape. What if the probability of fine tuning is less than 1:10500? This may be especially problematic concerning the arbitrary initial conditions. Finally, does the multiverse itself described by M-Theory exhibit fine-tuning? If it does, then the problem has only been pushed back a notch. It seems that it does, for as Hawking and Mlodinow note, M-Theory requires precisely eleven dimensions if it is to be viable, and yet the theory cannot account for why just that number of dimensions should exist.

Moreover, Mlodinow and Hawking do not even mention, much less respond to, Roger Penrose’s trenchant criticism of the Many Worlds Hypothesis for explaining fine-tuning in his The Road to Reality, namely, that if we were just a random member of a World Ensemble, then it is incomprehensibly more probable that we should be observing a much different universe than what we do, which strongly disconfirms the Many Worlds Hypothesis. There’s no excuse for Hawking’s failure to respond to his erstwhile collaborator’s criticisms of Hawking’s view.

In summary, despite Hawking and Mlodinow’s vaunted assertions and constant sniping at religious belief throughout this book, there is actually genuine profit in it for religious believers, especially for those interested in natural theology. With respect to the kalam cosmological argument, the authors’ preferred theory affirms the fact of an absolute beginning of time and the universe, which is the key premiss of the argument. With respect to the teleological argument based on fine-tuning, the authors affirm the fact of the apparently miraculous fine tuning of the universe for intelligent life. Moreover, they agree that the fine-tuning cannot be plausibly explained as due to physical necessity or by chance in the absence of a World Ensemble. Given the desperation and/or irrelevancy of their proffered ways to escape these arguments, their book turns out to be quite supportive of the existence of a transcendent Creator and Designer of the cosmos.

 

Athugasemdir

[Sveinn Þórhallsson, 4.10.2010 kl. 15:35]

Góðar og gildar spurningar hjá Gunnari, flestar allavega. Ég er hins vegar ekki viss um að W.L.C. sé rétti maðurinn til að svara þeim og ráðlegg honum því að bíða eftir bókinni.

[Mofi, 4.10.2010 kl. 15:50]

Sveinn, ég held að það er engin spurning að álit W.L.C. er gott innlegg í þessa umræðu. Maður á auðvitað að svara svona hlutum fyrir sjálfan sig en oftar en ekki þá þarf maður álit nokkura aðila til að komast að upplýstri svari, þótt það sé bara fyrir mann sjálfan.

[Sveinn Þórhallsson, 4.10.2010 kl. 16:11]

Sammála því að oft þarf maður að styðja sig við álit annarra, en hvers vegna ætti álit W.L.C. að vega þungt einmitt í þessari umræðu? Maðurinn er enginn sérfræðingur í kennilegri eðlisfræði eða heimsfræði.

[Mofi, 4.10.2010 kl. 16:35]

Sveinn, hann er vel að sér í þessari umræðu, hvað orsakaði heiminn. Ég sagði síðan bara "gott innlegg" í svona umræðu. Ég hafði að minnsta kosti gaman af þessu svari hans og lýsa góðu innsæi í þetta efni.

[Sveinn Þórhallsson, 4.10.2010 kl. 16:44]

Jæja, ég býð samt eftir bókinni og rökum Hawkings áður en ég mynda mér skoðun og ráðlegg þér, Gunnari og Craig að gera slíkt hið sama.

[Mofi, 4.10.2010 kl. 17:03]

Sveinn, hlakka til að sjá hvað kemur út úr því.