Has physics done away with God? A newly release book by Stephen Hawking and Leonard Mlodinow says, “Yes.”
What is a Jewish or Christian believer to make of this? Is the Creator now out of a job? The short answer is (unsurprisingly) no: the ideas propounded in Hawking’s book constitute no threat whatever to the Jewish and Christian doctrine of Creation.
The idea that Hawking is now touting is not new—in fact, within the fast-moving world of modern physics it is fairly old. My first introduction to it was reading a very elegant theoretical paper entitled “Creation of Universes from Nothing,” written in 1982 by the noted cosmologist Alexander Vilenkin, who argued that our universe might have arisen by a “quantum fluctuation.”
This idea is sometimes referred to as the quantum creation of the universe. There are different variants, but the basic idea is well-known among particle physicists and cosmologists.
Right up front, it must be noted that this idea is extremely speculative, has not yet been formulated in a mathematically rigorous way, and is unable at this point to make any testable predictions. Indeed, it is very hard to imagine how it could ever be tested. It would be more accurate to call these “scenarios” than theories. It would be a mistake, however, for religious believers to dismiss these scenarios as mere fanciful conjecture or as motivated merely by atheist ideology. Based on a plausible analogy with the experimentally observed and well-understood phenomenon of the quantum creation of particles, the idea of quantum creation of universes is not without merit.
The salient point has to do with how quantum mechanics works. In quantum mechanics one always considers some physical “system”, which has various possible “quantum states”, and which is governed by certain well-defined “dynamical laws.” These dynamical laws that govern the particular system and the fundamental principles of quantum mechanics allow one to calculate the probability that the system will make a transition from one of its states to another. To take a simple example, the system might be an atom of hydrogen, and its states would be the different “energy levels” of the atom.
The highly speculative idea is that these ways of thinking can be applied to entire universes, which is what Hawking (and many others) have tried to do. For physicists (as opposed to theologians and metaphysicians) the concept of the universe does not refer to “all there is” or the “totality of things.” It refers to a single, self-contained physical structure, comprising a “spacetime manifold” and particles and other things moving around in that spacetime.
If one thinks of a universe as a particular structure, then one can imagine a multiplicity of universes, with universes coming into and going out of existence in various ways. For example, a new universe might split off from an already existing universe in a manner analogous to the way a small balloon can be “pinched off” from a larger balloon. Or one can imagine a universe starting off as a point of zero size (which is, in effect, no universe at all) and then growing continuously to some finite size.
By such processes, the number of universes can change. However, we need to keep in mind the special way in which physicists use the concept of “universe,” for these various universes are really features of a single overarching physical system—call it a “system of universes”. When the number of universes changes, it is because that single overarching system has undergone a transition from one of its “quantum states” to another. Such transitions are precisely governed by dynamical laws (assumed to include the laws of quantum mechanics). These laws would govern not only how many universes there were, but the characteristics of these universes, such as how many dimensions of space they could have and what kinds of matter and forces they could contain.
Some states of the system of universes would correspond to just one universe being in existence; others to two universes, and so on. And there would also be a state with no universe in existence. The dramatic possibility Hawking is considering (and many others before him) is that such a system might make a transition from its “no-universe state” to a state with one or more universes.
Would this be “creation” in the sense that theologians mean it? And in particular, would it be creation ex nihilo, creation from nothing?
The answer is no. First of all, one isn’t starting from “nothing.” The “no-universe state” as meant in these speculative scenarios is not nothing, it is a very definite something: it is one particular quantum state among many of an intricate rule-governed system. This no-universe state has specific properties and potentialities defined by a system of mathematical laws.
An analogy may help here. A checking account is a system that has many possible states: the zero-dollar state, the thousand-dollar state, the negative-thousand-dollar state (if one is overdrawn), the million-dollar state, etc. And this system can make transitions from one state to another. For instance, by a finance charge or by accruing interest. Even if your checking account happens to be in the zero-dollar state one day, the checking account is nevertheless still something definite and real—not “nothing.” It presupposes a bank, a monetary system, a contract between you and that bank—all being governed by various systems of rules.
Imagine the day on which your bank account balance is zero. Then imagine a deposit the next day that raises it to one thousand dollars. A quantum theory of the creation of a universe (in Hawking’s version, or Vilenkin’s, or anyone else’s) is akin to this transition from an empty account to one full of money. Obviously, therefore, the “nothing” that Hawking makes part of his theory of the creation of our universe is not nothing in a metaphysical sense. The “no-universe” of his speculations is like the “no-dollars” in my account. It exists within the framework of a complex overarching system with specific rules. So we can see that, if true, the way of thinking put forward by Hawking does not threaten the classical doctrine of creation out of nothing.
Perhaps my explanations are not really necessary. Even the most casual readers recognize that the cosmological theories put forward by Hawking do not bear upon larger questions that motivate classical views of creation out of nothing. Non-scientists are quick to ask the obvious questions. Why a system obeying quantum mechanics, M-theory, superstring theory, or whatever laws of physics that make scientific speculations possible in the first place? Why not no system at all, with no laws at all, no anything, just blank non-being?
Physics, by its very nature, cannot answer these questions. And the funny thing is that Hawking himself is perfectly aware of this. Indeed, he said it himself in a previous book! In A Brief History of Time, Hawking observed—quite correctly—that any theory of physics is “just a set of rules and equations.” And he asked, “What is it that breathes fire into the equations and makes a universe for them to describe? The usual approach of science of constructing a mathematical model cannot answer the question of why there should be a universe for the model to describe.” (Here he was using the word “universe” to mean what I called the “system of universes”: the entirety of physical reality described by the laws of physics.
Physics scenarios and theories are merely mathematical stories. They may be fictional or describe some reality. And just as the words of a book by themselves can’t tell you whether it’s fact or fiction—let alone have the power to make the world they describe real—so with the equations of a physics scenario. As Hawking once understood, equations may turn out to be an accurate description of some reality, but cannot not confer reality on the things they describe.
What Hawking called in his previous book the “usual approach of science” is in fact the only genuinely scientific approach. From the time Hawking wrote that earlier book until now, nothing has changed in this regard: theories of physics are still “just sets of rules and equations.”
There are two answers to the question: “Why does anything exist rather than nothing at all?” The atheist answers, “There is no explanation.” The theist replies, God. An intelligent case can be made for either answer. But to say that the laws of physics alone answer it is the purest nonsense—as Hawking himself once realized.
Stephen M. Barr is professor of physics at the University of Delaware and author of Modern Physics and Ancient Faith.