Talk given on Nov. 7, 2012 at the Boulder Socrates Cafe.
I write and lecture a lot about science and religion. A common question I get from religious believers is ŌHow can something come from nothing?Ķ They seem to think itÕs the final clincher proving the existence of God—or at least some form of supernatural creation. Of course, they donÕt say how God came from nothing. Or, if they do, they claim God always existed and so did not have to come from anything. But then, why couldnÕt the universe have always existed? In fact, modern cosmology suggests that it did—that the universe is eternal.
First we have to try to define what we mean by Ōnothing.Ķ ItÕs not easy. To define nothing we have to give it some defining property. But then, itÕs no longer nothing! You would think that to be nothing it would have to have no properties. But then, isnÕt having no property a property? See what a mess we can get ourselves into when we spend our time arguing over definitions?
However, I think I can reformulate the believerÕs legitimate question so that it doesnÕt bog us down with trying to define some abstract notion of nothing. ItÕs now well established that our universe began 13.7 billion years ago with an explosion called the big bang. The believer is basically asking: ŌHow could that have happened naturally?Ķ
For example, we know that the universe has mass. So, a good question is, where did that mass come from? Now, Einstein showed that mass can come from energy. But then, where did energy come from? If it was natural, it had to come from something. It would seem, then, that a miraculous violation of the law of conservation of energy was required to create the universe.
Until just a few decades ago, this was a good argument. Since then, cosmology has become a remarkably precise empirical science with data from spectacular new telescopes on Earth and in space. With these instruments, the average energy density of the universe has been accurately measured and found it to be exactly what it should be if the universe arose from a state of zero energy, give or take quantum fluctuations. What happens is that the positive energy associated with mass and motion is almost exactly balanced by the negative potential energy of gravity.
Without going into the technical details, I can simply say that we know of no laws of physics being violated in the creation of our universe.
Now, you may ask—as many do—where did the laws of physics come from? One of the great theoretical discoveries in the 20th century, which we never read about in the popular media, is that the laws of physics follow naturally from the basic symmetries of nature—or the accidental breaking of those symmetries. Since nothing is more symmetric than nothing, you can say that the laws of physics came from nothing, with some random chance stirred into the pot.
In short, we have no scientific reason to suppose a miraculous creation, whether from nothing or something.
What about the other common question: ŌWhy is there something rather than nothing?Ķ Yesterday, Larry handed me a quotation from a new book just published called Why Does the World Exist? by Jim Holt. The quotation is supposedly a proof of why there must be something rather than nothing.
IÕm not going to read the so-called proof, because it doesnÕt really matter. The author doesnÕt seem to understand one of the first principles of logic: A purely logical proof can tell you nothing about the world that is not already embedded in its premises. You canÕt prove anything about the world by words alone. You need data, empirical evidence, to form the basis of your premises. Then you can carry out your deductions from those premises.
Although I havenÕt read his new book, I was already familiar with Holt. In June, he wrote an op-ed for the New York Times titled ŌPhysicists, Stop this Churlishness.Ķ In it, he criticized the comments made by several physicists, notably the late Richard Feynman, about the ineffectiveness of philosophy.
Holt remarks that the ancient Greek philosophers, Leucippus and Democritus, who came up with the idea of atoms did it by Ōpure thoughtĶ rather than observations and controlled experiments. In other words, Holt claims that we can learn about the world by thought and reason alone.
This is dead wrong. The ancient atomists inferred their idea of invisible atoms from observations such as the effects of wind and the random motions of dust motes in a sunbeam. In fact, this phenomenon, known as Brownian motion, provided the final empirical confirmation of the existence of atoms in the early 20th century. In fact, Einstein provided the equations needed in a paper he published in 1905, the same year he produced his more famous papers on relativity and the photoelectric effect.
In any case, before we even need proceed with trying to answer why there is something rather than nothing, the believer has the burden of answering several questions:
1. Why is there God rather than nothing?
2. Why should nothing rather than something be the more natural state, the default state of reality so that some action is needed to make something? Maybe action is needed to make nothing out of something.
3. Is it even possible for there to be nothing? Some philosophers have said no—that the whole concept is incoherent, as IÕve already implied in my discussion of definitions.
Actually, physics has something to say about this issue. Physical systems tend to change naturally and spontaneously from less structured to more structured states. For example, in the absence of external heat, water moves spontaneously from largely unstructured vapor to more structured liquid, to highly structured ice.
Another way to say this is that simple systems tend to spontaneously change into systems of greater complexity. This is widely misunderstood. In fact, the whole notion of intelligent design is predicated on the claim that a complex system requires a more complex designer. Wrong. In nature, simplicity begets complexity.
And, what could be simpler than nothing, however conceived? In a 1980 Scientific American article, Nobel-Prize-winning physicist Frank Wilczek wrote in answer to the question of why there is something rather than nothing, ŌNothing is unstable.Ķ In other words, even if there were a state of nothing, it would not last but automatically become something.
Now, I could stop at this point. However, thereÕs a lot more I can say based on our current best knowledge of physics and cosmology—in particular, how that knowledge contradicts common religious beliefs.
LetÕs go back to 1970, when we were all young. Well, most of us. In that year, a graduate student at Cambridge named Stephen Hawking joined with mathematician Roger Penrose to derive what is called the ŌPenrose-Hawking singularity theorem.Ķ They used EinsteinÕs general theory of relativity to prove that the universe began as a singularity, which is a point in space-time of infinitesimal size and infinite energy density.
Since then, theologians have used this theorem to argue that not only the universe, but time itself must have begun at that point. This confirmed the teaching of St. Augustine that supposedly answered the question of what God was doing before he created the universe. According to Augustine, there was no before. When God created the universe, he also created time.
In any case, modern theologians argue that since everything that begins must have a cause, then a supreme being outside of space and time must have created space, time, and matter at that instant.
Actually, everything that begins need not have a cause. In particular, quantum events such as atomic transitions and nuclear decays have no cause.
Nevertheless, for for almost two decades now, theologians and religious apologists have insisted that that had the clincher—scientific evidence for a creator: the big bang had to be the beginning of time as well as everything else.
But they were wrong. In his 1988 blockbuster best seller A Brief History of Time, Hawking admitted that, while the Penrose-Hawking theorem was mathematically correct, no singularity actually occurred at the beginning of our universe. This was because the general theory of relativity, on which the theorem is based, is not a quantum theory. It breaks down at very small distances and times when quantum effects come into play.
Although Hawking wrote this almost a quarter-century ago, you still hear theologians making the same argument. They know better, but their typical audiences donÕt. Today, all professional cosmologists, including Penrose, agree that the universe did not begin as a singularity.
As best as we can tell, our universe emerged 13.7 billion years ago from a tiny region about 10-35 meters in diameter that was in complete chaos. It had no structure and so we can just as well call it Ōnothing.Ķ
Around 1980, it was shown theoretically that a universe empty of matter and energy would undergo a very rapid, exponential expansion. This was dubbed inflation.
When physicists attempted to produce models for inflationary cosmology, they found that space continued to inflate exponentially while now-and-then and here-and-there bubbles formed like gas pockets in a rising loaf of bread. It was realized that each of these bubbles must be a separate universe. Within these bubbles, inflation stops, matter is formed, and the familiar big bang takes over. Our universe, then, is just one of those bubbles. The other bubbles are other universes that might be similar to our own—or very different.
According to the models, the space between bubbles continues to exponentially inflate, producing more bubbles. This scenario is called Ōeternal inflation.Ķ And so, according to this scenario, we are a part of an unlimited number of universes called the Ōmultiverse.Ķ
Theologians and some scientists have raised objections to this picture of an eternal, uncreated multiverse:
1. ItÕs unscientific since we cannot observe other universes.
2. It violates OckhamÕs razor by postulating too many unnecessary entities.
3. If the universe goes back an infinite time in the past, then it would have taken an infinite time to reach the present.
Let me answer each of these in turn.
1. The multiverse is scientific. We often deal with unobservables in science, such as quarks and black holes. Eternal inflation is not pure speculation; it depends on well-established knowledge. Furthermore, we may be able to detect another bubble universe by measuring distortions in the cosmic background radiation caused by its gravitational interaction with us. This could have happened right after bubble formation when we were still relatively close. In fact, there are some observational hints already, but they are not statistically significant. The Planck space telescope, launched in 2009, may be able to obtain such evidence.
2. OckhamÕs razor actually favors the multiverse hypothesis. The logical principle called OckhamÕs razor forbids adding unnecessary hypotheses to a theory—not the objects in a theory. For example, the atomic theory multiplied the number of objects in a body by a trillion-trillion. But the atomic theory had fewer hypotheses than macroscopic thermodynamics and explained much more. Assuming a single universe requires an additional hypothesis, namely a currently unknown principle forbidding more than one universe.
3. And finally, the multiverse did not begin an infinite time ago. It had no beginning. The time from any moment in the past to now is finite. The multiverse is eternal. It went on forever in the past and will go on forever in the future--it has neither a beginning nor an end.
So, how can the multiverse have come From Nothing? Since the multiverse always existed, it didnÕt have to come from anything.