In part 1 of this review, I argued that the lack of a unified theory of gravity and quantum mechanics is what has stymied scientists in their attempt to understand the origins of our universe and even what came ‘before’, assuming that the question even makes sense. M-theory and the no boundary condition is what Hawking proposes as the candidate for a unified theory that can address the physics of the early universe.
M-theory is not an elegant theory expressed in a single equation (like Newton’s law of gravity) or even a few equations (like Maxwell’s equations of electromagnetism) but instead consists of a patchwork of theories, each with its domain of application, and overlapping with other theories so that the whole space of nature is covered. Hawking argues that this patchwork feature may not be due to our lack of imagination or inventiveness but intrinsic to the nature of the laws of science.
It is like the way we create accurate but flat maps of the Earth’s surface. Because the Earth’s surface is curved, no single flat map can ever do the entire job for us. Instead we are forced to take small portions of the globe and map each region separately. As long as the boundaries match up correctly, we effectively have a global flat map, although such a collection is not as elegant as having a single flat map. The versions of M-theory in each domain are referred to as ‘effective’ theories and are supposedly as real as those theories can get.
One big problem with dealing with the origins of the universe is how to deal with the so-called ‘singularity’ problem, in which the gravitational fields are so large due to the compression of the universe into a tiny space that space becomes so warped that the laws of physics we have (which were designed for flat spaces) break down. Hawking suggests that there is a way to overcome this hurdle, which he calls the ‘no boundary’ condition. He says that, “once we add the effects of quantum theory to the theory or relativity, in extreme cases warpage can occur to such a great extent that time behaves like another dimension of space.” (p. 134) This is because of a technical maneuver in which time is treated as an imaginary quantity. (‘Imaginary’ in the scientific sense has a very precise mathematical meaning and does not have the everyday meaning of existing only in one’s head.) “The realization that time behaves like space… removes the age-old objection to the universe having a beginning, but also means that that the beginning of the universe was governed by the laws of science and doesn’t need to be set in motion by some god.” (p. 135) (In chapter 8 of his earlier book A Brief History of Time Hawking describes the no boundary proposal in more detail and says that its predictions have been borne out.)
The amalgamation of M-theory with the no boundary condition is the central feature of Hawking’s argument.
M-theory itself is a combination of string theory (in which elementary particles are assumed to be not point-like but like bits of vibrating string, either open or closed in loops) and supergravity (which itself is a combination of the theory of gravity and a theory of particle physics known as supersymmetry, one feature of which is that every particle we are familiar with has to have a partner particle with specific properties.)
M-theory requires eleven space-time dimensions. We cannot directly determine (at least as yet) the form of the laws of science in the eleven-dimensional space. Since we appear to exist in four space-time dimensions (three space and one time), the absence of those other dimensions need to be explained. The unobservable seven dimensions are assumed to be curled up to be so tiny that we cannot detect them at the present time with our present technology, giving us the illusion that we live in just four dimensions. The way the seven extra dimensions curl up is not uniquely determined and how they do so determines the nature of the laws we perceive in our reduced four-dimensional space. The number of ways in which they can be curled up, and hence the resulting number of potential universes each with its own laws and matter and parameters, can be as high as 10500! This is a staggeringly high number that is hard to even wrap our minds around but, as I will discuss in the next part of this review, it plays an important role in answering the questions raised in the book.
Richard Frost says
Thanks for explaining this in layman’s terms. I get the impression from your review to date that you are not quite convinced by this “M-Theory” and regard it as merely an attempt at a unifying theory, not the finished article. Please correct me if I’m wrong.
Has Stephen Hawking changed his mind? One of the (obviously religious) commenters on Sean Carroll’s review quoted Hawking in his 2002 work, The Theory of Everything: “It would be very difficult to explain why the universe should have begun, except as the act of a God who intended to create beings like us. The whole history of the universe can be said to be the work of God.”
It was interesting to see Carroll himself conclude with the verdict that Hawking is picking an unnecessary fight with the philosophers, even while quoting a few of them throughout the book. Carroll states: “Answers to the great ‘Why?’ questions are going to be subtle and difficult. Our best hope for constructing sensible answers lies with scientists and philosophers working together, not scoring points off one another.”
Presumably, you are not with Carroll on this one, as this sentiment smacks of accommodationism, doesn’t it? Anyway, I understand if you’d rather wait until part four of your review to respond.
In general I am skeptical of any claim to a “final” theory of anything. I think knowledge always evolves. All current theories are the best we’ve got but they could, and likely will, get better.
I will deal more with this issue and with Hawking’s views on god and philosophy in the final part of the review.
Ron Krumpos says
Do you believe anything is infinite and eternal, i.e. with no spacetime boundaries?
Our best current theories say that the universe is infinite and eternal, at least in the sense that it will go on forever.
Carroll’s view about scientists and philosophers working together is not accommodationism, unless he is talking about philosophers who are theists with an accommodationist agenda. I am pretty certain he is not talking about them.
There are plenty of philosophers who are flat out atheists.
Not sure if you’ve seen this Mano, but I like this YouTube video that explains the 11 dimensions. I’m not sure if this is in line exactly with what you’re currently discussing.
There is another video on that channel called ‘Imagining the tenth dimension’ which is also helpful. Well, at least to my math challenged mind.
I don’t know if you’ve seen this morning’s XKCD, but it seemed amusingly germaine to your Stephen Hawking discussion:
I disagree with what you type on the philosophers and scientists. I think you think wrong. Where did you get this information?
Steve LaBonne says
Kartvizit, I’m not quite sure what you’re trying to say, but surveys of philosophers have shown that outside the hothouse domain of philosophy of religion, the great majority are atheists (overwhelmingly so in certain fields, like neurophilosophy / cognitive philosophy.) Collaboration with philosophers doesn’t have the slightest thing to do with accomodationism. Neurobiologists and philosophers have been productively collaborating for years.
Steve LaBonne, i think you’re wrong. I do not think that philosophers of cooperation. Still, I respect your opinion:)
Udaybhanu Chitrakar says
Philosophy is dead. Is Logic dead also?
“Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist.”
-- Stephen Hawking in “The Grand Design”
“As recent advances in cosmology suggest, the laws of gravity and quantum theory allow universes to appear spontaneously from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.”
-- Stephen Hawking, Ibid
Here three questions can be asked:
1) Which one came first, universe, or laws of gravity and quantum theory?
2) If the universe came first, then how was there spontaneous creation without the laws of gravity and quantum theory?
3) If the laws of gravity and quantum theory came first, then Hawking has merely substituted God with quantum theory and laws of gravity. These two together can be called Hawking’s “Unconscious God”. Therefore we can legitimately ask the question: Who, or what, created Hawking’s unconscious God?
Not only this, but there are other problems also. If the laws of gravity and quantum theory allow universes spontaneously appearing from nothing, then initially there was nothing. Then wherefrom appear those laws of gravity and quantum theory to allow universes appearing spontaneously from nothing? In which container were those two laws of nature?
Now regarding the M-theory: I have already written something on multiverse theory (not yet published anywhere). There I have come to the conclusion that if there are an infinite number of universes, then only within that infinite number of universes there will certainly be at least one universe in which life will emerge. If the number of universes is only 10 to the power 500, then it is very much unlikely that any one of them will support life, because no universe will know which set of values the other universes have already taken, and if everything is left on chance, then there is every probability that all the universes will take only those set of values that will not support life. There will be no mechanism that will prevent any universe from taking the same set of values that have already been taken by other universes. There will be no mechanism that will take an overview of all the universes already generated, and seeing that in none of them life has actually emerged will move the things in such a way that at least one universe going to be generated afterwards will definitely get the value of the parameters just right for the emergence of life. Only in case of an infinite number of universes this problem will not be there. This is because if we subtract 10 to the power 500 from infinity, then also we will get infinity. If we subtract infinity from infinity, still then we will be left with infinity. So we are always left with an infinite number of universes out of which in at least one universe life will definitely emerge. Therefore if M-theory shows that it can possibly have 10 to the power 500 number of solutions, and that thus there might be 10 to the power 500 number of universes in each of which physical laws would be different, then it is really a poor theory, because it cannot give us any assurance that life will certainly emerge in at least one universe. So instead of M-theory we need another theory that will actually have an infinite number of solutions.
Now the next question to be pondered is this: How did the scientists come to know that an entire universe could come out of nothing? Or, how did they come to know that anything at all could come out of nothing? Were they present at that moment when the universe was being born? As that was not the case at all, therefore they did not get that idea being present at the creation event. Rather they got this idea being present here on this very earth. They have created a vacuum artificially, and then they have observed that virtual particles (electron-positron pairs) are still appearing spontaneously out of that vacuum and then disappearing again. From that observation they have first speculated, and then ultimately theorized, that an entire universe could also come out of nothing. But here their entire logic is flawed. These scientists are all born and brought up within the Christian tradition. Maybe they have downright rejected the Christian world-view, but they cannot say that they are all ignorant of that world-view. According to that world-view God is omnipotent, omniscient and omnipresent. So as per Christian belief-system, and not only as per Christian belief-system, but as per other belief-systems also, God is everywhere. So when these scientists are saying that the void is a real void, God is already dead and non-existent for them. But these scientists know very well that non-existence of God will not be finally established until and unless it is shown that the origin of the universe can also be explained without invoking God. Creation event is the ultimate event where God will have to be made redundant, and if that can be done successfully then that will prove beyond any reasonable doubt that God does not exist. So how have they accomplished that job, the job of making God redundant in case of creation event? These were the steps:
1) God is non-existent, and so, the void is a real void. Without the pre-supposition that God does not exist, it cannot be concluded that the void is a real void.
2) As virtual particles can come out of the void, so also the entire universe. Our universe has actually originated from the void due to a quantum fluctuation in it.
3) This shows that God was not necessary to light the blue touch paper and set the universe going, as because there was no creation event.
4) This further shows that God does not exist.
So here what is to be proved has been proved based on the assumption that it has already been proved. Philosophy is dead for these scientists. Is it that logic is also dead for them?