The first clue that we are dealing with two entirely different kinds of questions is the equivocation in terminology that Hawking has employed.
Hawking and Mlodinow have made several claims, one of which is that it is scientifically possible for "universes" to have "appeared spontaneously from nothing." And from this some people have even concluded that the fundamental question "Why is there something rather than nothing?" has been answered.
But for starters, just because you have discovered that something is possible, you have not thereby discovered why it exists. In fact, everything that we encounter in life we know is possible, since it, in fact, exists, and everything that exists must obviously be possible. But we do not by that mere fact know why these things exist: that is another question entirely. Excerpts from Hawking's book seem to indicate that, whether or not he thinks the question has been answered, he does at least think it is scientifically answerable.
The confusion starts with Hawking's use of terminology. What exactly does "universe" mean for Hawking, and what does "nothing" mean when he says it is possible for the universe to come from nothing? Is he using these terms the way philosophers use them--or for that matter the way the rest of us do?
When most of us use the term "universe" we mean it as the Oxford Dictionary defines it: "all existing matter and space considered as a whole; the cosmos." Hawking however uses an equivocation. For him there is more then one universe. So when he says "universe" he does not mean "all existing matter and space considered as a whole; the cosmos." As physicist Stephen Barr, writing in First Things, points out:
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.The second terminological problem has to do with the word "nothing." Does Hawking actually mean "nothing" as the negation of "something"? Does he really mean the absence of any thing, as he must know most of us hear it when he uses the term? Barr again:
... 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”.
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.Barr uses the analogy of a bank account with no money in it. It is itself empty: it has nothing in it. But the account itself exists, within the existing banking system. So in one sense you could say the account is "nothing" because it has nothing in it. It contains no value. But if, the next day, a thousand dollars is credited to the account, was it something from nothing? And if the bank account is "nothing," then how could it be there to receive the thousand dollars?
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.For Hawking to equivocate in his use of these terms in relation to how others outside physics use them is not necessarily a problem when he is talking to other physicists, but when he goes before the public and fails to note that he is using them in a different way, it would seem he bears some of the responsibility for the confusion that might ensue--and which, in fact, has ensued. And the problem is made worse when you consider that Hawking himself uses these terms in equivocal ways in his own books. In the excerpts that have been published of his new book, he uses the term one way, and in his book A Brief History of Time, he uses it in quite another.
... 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.
In fact, Barr points out that Hawking himself once seemed to understand the limitations of physics and understood that, by its very nature, it cannot answer the questions he seems now to think it can, citing this quote from Hawking in Brief History of Time:
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.I think Barr slightly overstates the case here. This quote comes from the conclusion of the book, where you can see the seeds of Hawking's confused view of physics and philosophy. There, Hawking does say that the "why" questions are the province of philosophers, but then he goes on to argue that because philosophers have not been able to keep up with the advances in science and mathematics, physicists--and everyone else--now get to answer philosophical questions. He says, "However, in the nineteenth and twentieth centuries, science became too technical and mathematical for the philosophers, or anyone else except a few specialists." He then cites Wittgenstein as an example of a philosopher who limited philosophy to analyzing language rather than answering the big questions. "What a comedown," he says, "from the great tradition of philosophy from Aristotle to Kant!"
"Traditionally these are questions for philosophy," says Hawking, "but philosophy is dead."
Huh? In what sense is philosophy "dead"? And how would Hawking know? The only way you could say that philosophy is "dead" is to say either that the questions it asks have been answered or that no one is trying to answer them anymore. But you can't say either. Hawking himself believes that the questions of philosophy are still unanswered, and thinks that physics can answer them. And anyone who thinks there is no one trying to answer them apparently haven't noticed that there are still quite a few philosophers around.
Actually, there is one more way that you can say philosophy is "dead," and it has to do with the philosopher Hawking mentions: Ludwig Wittgenstein. But Wittgenstein didn't "give up" on the big questions, as Hawking seems to imply. Wittgenstein didn't view the role of philosophy as answering the big questions. He believed that there were no big questions to answer--or rather that the big questions were a linguistic illusion. The big questions were simply a product of a linguistic misunderstanding. Once we understood language ("relieved our mental cramp," he called it), we would understand that the big questions were not really questions, and didn't therefore need to be answered.
In other words, many modern philosophers like Wittgenstein simply stopped engaging in philosophy and chose instead to engage in the analysis of language, calling it philosophy. This kind of analytic philosophy certainly dominated professional philosophy in the 20th century, but real philosophy has been reasserting itself for the last 50 years or so and is doing just fine, thank you, despite the declarations of its death by people like Hawking.
In fact, it is interesting that, in arguing that science had become "too technical and mathematical for philosophers," Hawking would cite Wittgenstein, since Wittgenstein would be one of the great counter-examples to his case. Wittgenstein was a formidable mathematician. In fact, he was a crucial influence on Russell & Whitehead's Principia Mathematica, and much of his earlier work concerned the foundations of mathematics. His first three lectures at Cambridge when he was elected professor there (decades after, ironically, he had had a crucial part in founding the first great school of 20th century philosophy, logical positivism, and then single-handedly founding the second great school of 2oth century philosophy, ordinary language philosophy) were on mathematics.
And it doesn't help Hawking's case either to consider that there were philosophers like Bertrand Russell and Alfred North Whitehead writing books exploring the fundamental ground of mathematics like the Principia. In fact, the single case of Whitehead is enough to throw much of Hawking's case against philosophy into doubt.
Whitehead, a mathematician who taught and wrote extensively on mathematics, physics, and the philosophy of science, and who was a Fellow of the Royal Society--and who, in fact, was sitting in the audience when the Astronomer Royal announced the results of the experiment on the solar eclipse that showed that light rays bent when they passed by the sun, as Einstein predicted--even articulated a rival theory to Einstein's relativity. It was not successful, but there isn't much of a question that he understand the major discoveries in physics of the 20th century--both relativity and quantum theory.
The question is not whether philosophers have kept up with physics and mathematics over the last 150 years: many of them have. The question is whether physicists like Hawking have kept up with events of 2500 years ago. The great Greek philosophers would have seen right through Hawking's idea that you can answer philosophical questions through the tools of something like modern science.
And this is indeed Hawking's project. Hawking clearly thinks that, when a complete theory of everything is found--the theory that Einstein searched for in vain, the "grand design of the universe," the "single theory that explains everything"--it will, despite the fact that it is still a theory of the physical world, be able to answer philosophical questions. He pointed his readers in this direction at the end of A Brief History of Time:
However, if we do discover a complete theory, ... then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist.Of course, we can all take part in that discussion already to the extent that we are all philosophers, albeit amateur ones. The question is, can we do it as scientists. He recapitulates the current situation in his new book:
Over twenty years ago I wrote A Brief History of Time, to try to explain where the universe came from, and where it is going. But that book left some important questions unanswered. Why is there a universe--why is there something rather than nothing? Why do we exist? Why are the laws of nature what they are? Did the universe need a designer and creator?Now one important thing to note here is that he still doesn't claim, as media reports indicate he has--that we have such a theory yet. He only claims we are closer to such a theory. But it is the claim that such findings bear on the big question--which presupposes that it is even possible to gain the answers to philosophical questions through science--that should be (and really is) at the core of the debate. The question isn't whether God is out of a job. The question is whether science could ever even conceivably prove such a thing.
It was Einstein’s dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein’s day hadn’t made enough progress in understanding the forces of nature for that to be a realistic goal. And by the time I had begun writing A Brief History of Time, there were still several key advances that had not yet been made that would prevent us from fulfilling Einstein’s dream. But in recent years the development of M-theory, the top-down approach to cosmology, and new observations such as those made by satellites like NASA’s COBE and WMAP, have brought us closer than ever to that single theory, and to being able to answer those deepest of questions. [Emphasis added]
If it can't, if it is by it's nature unsuited to answer such questions, then the fact that we are "closer than ever" to a unified theory of the physical world (the entire thing, not just whichever universe we happen to inhabit) gets us no closer at all to answering these nonscientific, philosophical questions. If it can't answer these questions, then all the attention Hawking is getting to his new book--which contains ideas that are apparently not that new at all ("The idea that Hawking is now touting is not new—in fact, within the fast-moving world of modern physics it is fairly old."--Barr)--is the result not of anything warranting the attention, but simply of hype.
There are plenty of scientists who want to exclude certain views because they fall outside the realm of what they consider science. Religion is a good example of this. They relegate these things (like God) to the meaningless or irrelevant--even though the most they can logically say about them is that they are nonscientific. They want the right to exclude things from the meaningful, but there are others, like Hawking, who want the right to appropriate the nonscientific into the realm of the scientific if it suits their purposes. Answering the "why" questions of philosophy are a perfect example of this.
In one moment, they will say that "why" questions are irrelevant or meaningless because they are not scientific, and in the next moment they are saying--as Hawking now says--they can answer the "why" questions scientifically--that somehow if you can accumulate enough answers to the "what" or the "how" questions, you have the answer to a "why" question. But you can have all the answers to "what" or "how" questions you like, and they will never amount to the answer to a "why" question. It would be like saying you had accumulated enough dogs to amount to a tree, or that you had finally grown enough grass in your yard to constitute a cat.
Sir James Jeans, in his book Physics and Philosophy, pointed out:
The tools of science are observation and experiment; the tools of philosophy are discussion and contemplation. It is still for science to discover the patterns of events, and for philosophy to try to interpret it when found.Jeans identified three differences between physics and philosophy: differences of language, differences of idiom, and differences in method. They are different, and the difference makes a difference. Science can't refute philosophical ideas; it can only refute other scientific ideas--as his has done time and again and will doubtless continue to do.
It's the kind of thing you would think a smart guy like Hawking would know.