Today I went to a talk by Lawrence Krauss entitled “A Universe from Nothing”, which had the following abstract:
The question, "Why is there something rather than nothing?" has been asked for millenia by people who speculate on the need for a creator of our Universe. Today, exciting scientific advances provide new insight into this cosmological mystery: Not only can something arise from nothing, something will always arise from nothing. Lawrence Krauss will present a mind-bending trip back to the beginning of the beginning and the end of the end, reviewing the remarkable developments in cosmology and particle physics over the past 20 years that have revolutionized our picture of the origin of the universe, and of its future, and which have literally revolutionized our understanding of both nothing, and something. In the process, it has become clear that not only can our universe naturally arise from nothing, without supernatural shenanigans, but that it probably did.
In the first 45 minutes, he provided an animated and reasonably clear explanation of concordance cosmology, the current version of the Big Bang model, dating from the discovery in 1998 that the expansion of the universe is accelerating (rather than decelerating as one would expect from the attractive gravity of ordinary matter). This is exciting but now well-established work, which I've heard about a hundred times before, but was probably new to many of the people in the audience. It was peppered with occasional off-hand sneers at Republicans, Theology, and Young Earth Creationism, but for the most part it was a pretty valiant stab at popularizing an important set of 20th century discoveries.
The real reason I was there, of course, was to listen to his claims in the last 15 minutes that modern cosmology somehow points to the nonexistence of a Creator. His claim was that there is evidence that the universe came from "Nothing" according to physical processes, and this apparently is supposed to undermine the religious view that God created the world supernaturally. There were so many things wrong with this part of his talk, both a physics and a philosophical perspective, that I'm not entirely sure where to begin. But let's try anyway.
His Slam on Theology. Krauss said that Theology wasn't based on empirical evidence, so therefore he didn't believe it. That was it. He didn't seem to take any particular theological ideas seriously enough to even try to define them, let alone refute them. There was no indication that Religion had any other origin besides a bunch of clueless dudes sitting around asking "Why is there Something rather than Nothing?" (In the case of Christianity, I thought it had more to do with a guy claiming to be God, doing miracles, and dozens of people saying that they saw him alive after he was killed. But what do I know?)
But let's get back to cosmology, since that was the subject of his talk. It used to be that Christians believed that the world was created a finite time ago, out of Nothing. Although some of them, like St. Thomas Aquinas, said that God could have created a universe with an infinitely long past. Atheists had (and have) a diversity of opinions, but most of them thought that things would make more sense if the universe were around forever, since then maybe you wouldn't have to explain where it came from. Then Big Bang cosmology came along, and it now seems—provisionally speaking—like the Universe really did have a beginning. Now some atheists think they can refute the Christian view that God created the Universe from Nothing by arguing that the world did emerge from Nothing. The role-reversal here is a little strange.
What Christians mean by creation ex nihilo is that God created the Universe, but that he didn't make it out of any pre-existing stuff that was lying around. Thus, while the universe didn't come "out of" anything, it still comes from God.
What Krauss seems to mean is something quite different, namely that there's some specific entity we can talk about called "Nothing", which has suitable properties for generating our universe.
But the universe can only come from nothing if you define a certain kind of something as being "Nothing". Duh, because any explanation by its very nature must explain one thing in terms of some other thing! This other thing must be taken for granted for purposes of the explanation. Now, Krauss actually referred to 3 different ideas which he called "Nothing #1, #2, and #3":
Nothing #1: an "empty" spacetime a.k.a. the vacuum. In ordinary non-speculative quantum field theory (QFT), the "vacuum state" (the configuration of fields with the lowest energy) is actually filled with so-called virtual particles which can affect physics in various ways. At least, that's what the popularized physics books say; if one actually studies quantum field theory rigorously, people tend to use somewhat different language since the notion of "virtual particle" can be difficult to define. But let's spot him the terminology since he was talking to a popular audience.
Krauss claimed that if you start with an empty space which has no virtual particles in it, virtual particles will appear, and this is "something" coming from "nothing". This is bosh, since strictly speaking, there's no such thing in QFT as a state with no virtual particles. (If there were, it would be infinitely different from the vacuum state, and would therefore have an infinitely large energy. That's not nothing at all!) If anything can colloquially be called "Nothing" in QFT, it is the vacuum state. But this state already has all those virtual particles in it. And as time passes, this vacuum evolves to....wait for it....itself! That's right, if you agree to call the vacuum state Nothing, then Nothing comes out of it. (He seemed to think this story might change once you take gravity into account, due to negative energies, but I didn't really understand this suggestion so I won't comment on it.)
The QFT vacuum isn't nothing. Of course, from a strict philosophical point of view, the vacuum state of QFT is not Nothing since it's filled with all those virtual particles, and even aside from that, there's the space and time geometry, which is not Nothing. To fix this he started taking up a different kind of nothing:
Nothing #2: the absence of any space or time. This actually connects to an interesting quantum gravity idea known as the "Hartle-Hawking state" or the "no-boundary boundary condition". (Jim Hartle is on my floor at UCSB, by the way.) The suggestion is that the laws of physics not only tell you how the universe at one time evolves to a later time, they also tell you what the initial state of the universe is.
In some sense, one can think of this state as emerging out of Nothing #2. However, the sense in which this is true is subtle. There's another sense in which the Hartle-Hawking state does not emerge from Nothing; rather it has existed for an infinite amount of time— the popular physics articles never mention this, for some reason! This is an interesting and important idea, but I think it deserves to be in it's own post, after I've explained QFT better. The important thing to know is the following:
The crucial physics here is totally speculative! It was entirely based on speculative ideas about quantum gravity which anyone working in the field would admit are not proven. This is because we currently have no experimentally testable theory of quantum gravity! (Nor do we even know how to formulate a consistent theory of quantum gravity mathematically, except perhaps in some special situations that probably don't apply to the beginning of our universe)
I mentioned this in the Q&A afterwards. My comment seemed to aggravate him a little, since he thought he'd been sufficiently clear about this. But I discovered that at least one member of the audience was still unclear on which parts were speculative, and which weren't, at the end of the lecture. In my experience, one has to be crystal clear about this sort of thing when speaking to a popular audience, or they tend to walk away thinking that "Science" has proven things when it hasn't.
Atheists such as Krauss scorn theology as being completely non-empirical. They claim it is not based on evidence of any sort. I find it extremely ironic when this sort of atheist thinks that speculative quantum gravity ideas are just the right thing to further bolster their atheism. Suppose you think that Science is better than Religion because it is based on evidence, and suppose you also want to refute Religion by using Science. Here's a little hint: consistency would suggest using a branch of Science that actually has some experimental data!
The universe has zero energy. Krauss thinks that the universe coming out of Nothing has been made more plausible by cosmology. To understand his terminology, you have to know that (roughly speaking) a closed universe means that space at one time is finite in volume, and shaped kind of like a sphere, so that if you travel around the universe far enough you come back to where you started. On the other hand, in a flat universe, space at one moment of time is shaped like ordinary Euclidean geometry, and is infinitely large. Current observations indicate that the universe is flat. As far as I could tell, Krauss' argument can be translated into these terms:
- The total energy of a closed universe is zero. (It's tricky to define energy in general relativity, but according to one commonly used definition, this is true.)
- Conservation of energy suggests that if the universe came from Nothing, it should have zero energy.
- If there was a period of extremely rapid expansion at the beginning of the universe (as evidence suggests there was—this is called inflation), then whether or not the universe started out closed, it should look flat today.
- But the universe does look flat,
- Therefore Science suggests that the universe was created out of Nothing,
- Therefore there is no need for God.
Perhaps I'm missing some crucial steps in his argument. But there seem to be several enormous leaps of logic in there.
The Hartle-Hawking state isn't Nothing either. Strictly speaking, even the Hartle-Hawking idea doesn't strictly get the universe out of Nothing, since it says that the initial state of the universe depends on the laws of physics. Now the laws of physics aren't nothing. So if, for example, you are wondering if there is any role left for the Creator, then one might say he picked the laws of nature.
Now, there's all sorts of difficult philosophical issues involved in what's called the Cosmological Argument for the existence of God. But it's hard to get into them with someone like Krauss who is so dismissive of Philosophy. The trouble with people like that is that it isn't possible to just find things out using Science instead of Philosophy. That's because you have to do Philosophy to know what is or is not implied by Science. People who dismiss Philosophy still end up doing it; they just do it badly, without a critical examination of their premises.
Nothing #3: the string theory multiverse. Krauss acknowledges that the laws of phyiscs themselves might seem to call for an explanation. Especially since the various constants of Nature seem to be "fine-tuned" to allow the existence of life (I'll go into this in much more depth later). On the face of it, this seems to be at least some mild evidence for the existence of God, but Krauss would never admit such a thing.
He suggests that we can explain this fine-tuning if string theory turns out to be true. That's because string theory has an enormous number of different possible configurations, that look like universes with different laws of physics. Some people have suggested that if there's a gazillion different universes (known as the "multiverse"), each with its own laws of physics, that it's not surprising that one of those universes should support life. Krauss admitted that there was some dispute as to whether this idea counts as "Science", what with it being totally speculative and arguably untestable. But what I want to know is, why the $@#& would we ever refer to an infinite number of universes, governed by the principles of string theory, as a Nothing?
I should say that this review is based entirely on Krauss' talk. I have not read his book, but I have read this negative review by philosopher St. Feser.
[Update 7/21/20: added two paragraphs to the text, beginning "What Christians mean..." to make the argument a little clearer.]
I'm not sure if you followed this at all, but there was quite a to-do about this book and a NYTimes book review my advisor (David Albert) wrote. His review of the book was pretty scathing, and it was the review and the resulting press that got the book a lot of its publicity. Krauss's response to the review was quite frankly embarrassing. He ultimately resorted to name calling and repeating himself, while completely misunderstanding the critiques. If you google it there's quite a bit out there about it. Several well known figures weighed in on it (I recall comments by Sean Carroll, for one).
The original review is at: http://www.nytimes.com/2012/03/25/books/review/a-universe-from-nothing-by-lawrence-m-krauss.html?_r=0
And, ultimately, I must agree. Krauss's argument is just, well... silly. Of course if we equivocate "nothing" we can get something from nothing. But, this is to profoundly misunderstand the Heideggerian question, "Why is there something rather than nothing?" (which I believe he is directly commenting on). I've only read sections of the book, but the structure of the argument is fairly clear. It's a classic case of what happens when you combine sloppy thinking with prejudice (and the desire to make dramatic statements that sell books).
Thanks for the link, JLW.
Let's assume for a moment that someone really knows god's word and he reveals to them that he created the universe from nothing. This person then went on to write it in a book for others to read. Saying "the universe came from nothing" is a moot point. What do we do with this knowledge? At the time it is presumed this idea started, it was of no use. If anything it would have been rejected, since that explains absolutely nothing about the universe. If we found that book today and confirm that assertion that the universe came from nothing it is still of no use to us, although we would recognize that the person was right.
This is what happened with Leucippus. Do you really think we are taking his theory seriously? No, we only had the courtesy of naming the atom by that name because he made a guess and he was actually right. He knew nothing about physics though.
Anyway, since people back then demanded some explanation, god had to be mentioned. That's why "god created the universe from nothing” is entirely different. Now you take an agent that we are presumably familiar with, god, and have him create the universe out of nothing. SINCE we know what/who god is, the sentence now attempts to explain something about the universe and therefore is accepted by the people.
The problem with this is obvious. It depends on the people being familiar with the concept of god. Only that initial person that wrote the book actually had knowledge of god. Anyone else just would not understand what god is. Therefore saying that god created the universe from nothing is also useless, it bears no message, no knowledge.
If, however, you assume everyone had knowledge of god the same as the writer of god’s word, then why in the world would god need to have his word written in a book? That action actually diminishes the possibility of god's existence. The people would have found out the same way and there would be no incentive to writing the book.
Many people throughout history have made some guesses on some subjects, and some had to be right. The fact that Christianity said something and it resembles what we know today does not mean Christianity knows anything about the universe.
If it did know something, it would be better than chance at answering questions correctly. I am pretty confident in saying that Christianity would be worse than chance at getting the right answers. One would be better off flipping a coin and calling heads and acting accordingly.
Saying that Christianity knew something in advance of the nature of the universe, is equivalent to having saying I knew in advance my favorite sports team (NE Patriots) would win the super bowl. I had the feeling; the season was good; it made sense. Could I be sure? Of course not, but they won; now everything seems to make sense in retrospect.
Please understand that any faith, religion, metaphysical or supernatural assertion has nothing to do with science. It was not made with the intention of developing a testable hypothesis, it was not made with the intention of learning anything about the world, it was made with the sole intention of giving an answer to a question, and since most people knew very little about the world around them, let alone the beginning of the universe, we are better off discarding all those assertions as most probably false. And i am leaving a little space for its possibility out of courtesy.
My post was not about how Christianity is great because it successfully predicted that the Universe came into existence out of Nothing. Instead it was about a certain atheist, Lawrence Krauss, who claims that Christianity is wrong because the Universe came out of Nothing, seemingly oblivious to the fact that this was a standard Christian belief.
But as for the origins of Christianity in particular, cosmological speculation had very little to do with it. As I wrote above:
"Most people knew very little about the world around them" but they were clever enough to realize that the usual physical laws don't normally permit virgins to give birth; people to walk on water; lepers, paralytics and blind people to be instantly cured; or dead people to spontaneously come to life again after a period of days.
This is a false dichotomy. By this argument, there would also be no point in reading a book about Psychology because either you have no knowledge of it (in which case you won't understand the book) or you have complete knowledge (in which case why read the book?) There is the possibility of intermediate forms of knowledge, in which case reading can be very helpful.
Did God Create Our Universe from Nothing? No
While Krauss's attempts to redefine nothing are really poor, to play the devil's advocate using Krauss's claims couldn't he say that the quantum vacuum that gave rise to our universe instead be the eternal fundamental reality or in terms of philosophy the necessary being that sustains existence. He could also say due to the principal of totalitarianism governing quantum mechanics, and the vacuum that our universe arising from the vacuum would have happened given enough time. I don't endorse this view as I see that due to vacuum being full of potentiality and having certain probabilities associated with events such as the creation of our universe, there is still a possibility that the vacuum at the instant it gave rise to our universe 13.7 billion years ago could have had different conditions that prevented it, even with the principle of totalitarianism, which would give it contingency even if our universe had to come eventually. Despite this the vacuum could still cause certain problems for theism for reason i stated above. Would you find it troubling for theism?
If the "quantum vacuum" were really the fundamental reality, it seems that once a universe arises, you don't have the "vacuum" anymore, and hence the necessary being would not exist eternally. In any case, such a being would require specifying the laws of physics, which would necessarily have some arbitrary features which might require explanation. Have you read my discussion of alternative naturalistic fundamental realities, and the rest of the series for my arguments that the fundmanetal reality must be more like a mind than an impersonal principle?
The "totalitarian principle" is the tendency in QFT, that anything which is not actually forbidden by conservation laws tends to happen with at least some tiny probability. It is not a theorem per se, just an observed tendency which makes sense due to the existence of quantum fluctuations. However, there is no garantee that this "totalitarian principle" continues to be true in quantum gravity, and I know of some evidence that it is not true (e.g. the probability of restarting inflation from flat Minkowski space seems to be exactly 0.)
The idea that a universe could tunnel from a "quantum vacuum" is a very speculative idea, and we don't know enough to say whether it makes sense or not. I'll take a Creator who has actually spoken to me over unproven physics ideas any day! For all I know, God began his act of creation by saying "Let there be a quantum vacuum, with X probability to tunnel into something else", and then he rolled some dice. But I strongly suspect his dice are loaded. ;-)
Thank your for your response, I've been looking more around your blog, and in one reply to a comment by a commenter you stated in QFT it is physically contingent which state the universe is in. If it was proven that the universe arose from a previous quantum vacuum state via random fluctuation and tunneling, would this contingency still apply to the vacuum state as if it preexisted the universe and henceforth the space time in our universe or would the fact that QFT describes and requires the spacetime manifold containing our universe make this contingency apply to the vacuum state as well.
First of all, the vacuum of QFT in Minkowski spacetime (Kruass' Nothing #1) is a completely different beast from the complete absence of spacetime (Krauss' Nothing #2). If we are talking about a universe coming from the latter, then we are outside the regime of validity of QFT. We'd need to have a theory of quantum gravity in order to really address the issue properly.
Contingency is more of a philosophical concept than a physics concept, but one physics question we can ask is whether the theory in question admits of other states, besides whichever one the universe happens to actually be in. We can't actually ask that question about Quantum Gravity very easily (since we don't know what the correct theory of quantum gravity is), but because (1) QFT has infinitely many states, and (2) under certain conditions QFT + weak gravity should be a very good approximation to Quantum Gravity, I would expect that a good theory of Quantum Gravity should also have many possible states, even in a closed universe.
But it's hard to know for sure. A possible counterargument is in the footnote of this post.
”Atheists such as Krauss scorn theology as being completely non-empirical. They claim it is not based on evidence of any sort. I find it extremely ironic when this sort of atheist thinks that speculative quantum gravity ideas are just the right thing to further bolster their atheism. Suppose you think that Science is better than Religion because it is based on evidence, and suppose you also want to refute Religion by using Science. Here's a little hint: consistency would suggest using a branch of Science that actually has some experimental data!”
But isn't there empirical data that suggests ”speculative quantum gravity” is real? It's not taken out of the blue, is it?
Anyway, the problem I have with religion/faith is that it's so arbitrary. Depending on who you ask there are all kinds of idea of what's ”true” when it comes to theology. May I ask what it is that makes you think Christianity stands out and is more believable than other religions and faiths on this planet?
The motivation for quantum gravity is almost entirely theoretical. Einstein's field equations yield equations of state and dynamics for the universe that, when extrapolated back in time to a point right after the big bang, eventually result in global space-time curvatures and densities (the two are interrelated) that run afoul of quantum uncertainty relations for distance/momentum and energy/time. At this point relativistic and quantum mechanical descriptions of all four become inseparable, and it's difficult to see how they can be accounted for without a marriage of the two. This, more than anything else, is why we believe that some sort of quantum gravity theory must be correct. But observing any of this is pretty much out of the question. The energy scales involved are virtually impossible to probe with current technology and it's unlikely we'll ever be able to. Observational cosmology doesn't help much either. Our telescopes (including all means of electromagnetic sensing) can only see back to around 379,000 years or so after the big bang. Prior to that the universe was opaque to radiation, which effectively blinds us from seeing what happened further back. There are a few ways to indirectly extrapolate some observational data to prior times, but nothing that takes us anywhere near to the big bang itself. Gravity wave telescopes may allow us to see further back some day, but the sensitivities required for this are still a long ways off.
To the best of my knowledge, there is only one way we might obtain empirical support for quantum gravity. Most inflationary scenarios predict the existence of primordial gravitational waves from quantum fluctuations that would've occurred at a time when quantum gravity effects should be pronounced (the so-called Planck era). If these waves are ever detected they could be taken as evidence of some kind of quantum gravitational activity taking place during that era. Beyond that, I don't know how we could ever obtain empirical evidence of any quantum gravitational activity, much less confirmation of a robust quantum gravity theory.
As for religion/faith being arbitrary, that's pretty open-ended. What are some of the aspects of it you find arbitrary, and in what manner? In my own faith the ways I've searched for, and identified 'true' are as varied as the questions I've waded through in my life. The answers that led me to Christ and Him crucified are far too involved to be addressed in a blog comment, but if there are any specific areas where you find Christian theology arbitrary or unconvincing I could share how I arrived at my own views on them. I imagine Aron and others here could do the same. Beyond that, you could do a lot worse than reading through Aron's many excellent postings on science and Christianity at this blog.
BTW, for what it's worth science can be pretty damn arbitrary too. Try wading through the last decade or so of literature on string/M theory and the multiverse. :-) Of course, this doesn't mean that science isn't revealing any truth to us; only that it's reached the bleeding edge of knowledge where questions and speculation are unavoidably the only path to further enlightenment. Religion, if it does anything at all, brings us face to face with questions of bedrock reality, who we are, and what our purpose is in this vast and beautiful universe. It would be really surprising if the same weren't true of it.
Ooops...! I meant to say that our telescopes can only see back to around 379,000 years or so after the big bang. We better be able to see farther back than 379,000 years ago... :-)
[I corrected your original comment--AW]
Aron, you say "e.g. the probability of restarting inflation from flat Minkowski space seems to be exactly 0."
1) is there any simple answer to why that is that I might understand?
2) about how many credits of math and physics courses would I have to take in order to understand the real answer?
1) There's a calculational technique in QM where you can figure out the probability for a quantum tunnelling event by making time imaginary (called "Wick rotation"---so instead of 3 dimensions of space and 1 of time, you consider 4 of space.
An inflating universe is described by something called de Sitter spacetime, but when you Wick rotate it, it becomes a sphere.
Minkowski space Wick rotates into ordinary flat Euclidean space.
So to calculate the tunnelling probability to restart inflation, you have to evaluate a certain number for a space which looks like part of the Euclidean plane glued to part of the sphere. This is a special case of something called the "Coleman-De Luccia instanton".
I haven't actually done the calculation, but I gather that at a certain point you end up dividing by the volume of the space corresponding to the initial condition. Since the volume of the Euclidean plane is infinity, this gives you 0. But if you go the other way, you get a finite answer. It's also finite if you have two spheres of different radii (corresponding to transitions between two positive values of the effective cosmological constant)
2) A few graduate courses plus a strong motivation to understand this specific problem ought to do it. As you can see, my motivation hasn't gotten quite strong enough to do the calculation myself yet, even though it gives a nice check on things I think follow from the Generalized Second Law.
My understanding of the zero-energy universe thing is that an attractive force (notably gravity) has negative potential energy 'at zero', since work would have to be done on the system to pull the objects apart. This could, in a quantum model, imply that gravitons have negative energy. Consequently, it would be possible for virtual graviton-massive-particle pairs to scatter into real particles. Though I am extremely unclear on why this would happen all at once and not by the minimal number of particles at a time. I don't know if any of that was what you were having trouble following. It may be you're getting tripped up on that last step, same as me.
I also don't get why gravity would be considered innately negative if photons are not, since it also takes energy to pull, say, an electron away from a proton. Besides which, since the concept of virtual states suggests that there is no absolute zero energy but only a minimum, the definition is somewhat arbitrary.
I voiced my thoughts on the HH state in that article. That's just a whole mess. If I had read this article's comments first, I would have seen the Wick Rotation bit. It doesn't really change my opinion but it does clarify things a bit.
Once scientists have come to the conclusion that space-time is not fundamental but emergent, now many things will change in physics. One such change is that scientists can no longer hold that the universe has originated from nothing.
This is because an entity that is emergent cannot emerge from just anything or nothing; it can emerge from some particular entity or entities only. Those scientists who are saying that the universe can and will create itself from nothing because there is a force such as gravity, are also saying along with it that space-time can also originate from nothing. So, here they are claiming that at the beginning of the universe space-time was fundamental because it had come straight from nothing, thus not requiring the prior presence of any entity/entities from which only it could emerge in case it was emergent.
But whatever knowledge scientists have acquired about the external world is from the present universe only. From the present universe scientists have acquired the knowledge about space-time that it is not fundamental. So, if they now claim that at the beginning of the universe space-time was fundamental, then our question to them will be: From where have they acquired the knowledge that space-time was fundamental at the beginning of the universe? Is it from the present universe? Or, is it from some supernatural source? Or, is it their intuition?
Have they themselves observed the universe directly coming from nothing? So, what is their source of knowledge that space-time was fundamental at the beginning?
Even if we assume the quantum gravity speculations are correct the interesting question then would be "who was there to make the observation to cause the wave function to collapse ?"
This article shows how a special class "Nothing" can logically build the universe. It also shows why this should follow logical
Keywords: Universe, Origin, Nothing, Logic, schizo-creations, Jocaxian-Nothingness.