Thursday, September 09, 2010

5 Questions for Stephen Hawking

On his website William Lane Craig has a podcast responding to Stephen Hawking's new book (The Grand Design [GD]) in which Hawking claims that the God hypothesis is unnecessary to explain the origin of the universe. Bill says:
  • He doesn't (at the time) yet have Hawking's book, so it would not be fair to comment on something he has not read.
  • From the media presentations of Hawking's book it appears Hawking says nothing new in this book that he has not already said in his best-seller A Brief History of Time. (BHT)
  • In BHT Hawking claimed that modern science allows no place for a creator of the universe. In BHT Hawking used quantum gravity to explain how the universe came into being from nothing. Then, he uses the many-worlds hypothesis (multiverse theory) in order to explain away the fine-tuning of the universe.
  • Bill encourages us to first read his book Reasonable Faith where he interacts with Hawking's BHT. 
  • In light of that ask the following questions as you look at Hawking's GD.
  • #1 - What new developments, what new theories, are featured in Hawking's new book? If there's nothing new in GD that's OK. The question then to ask is: How has Hawking responded to criticisms of his earlier work? There have been many responses, in the literature, to Hawking's earlier claims. Does he now, in GD, respond to those criticisms, and if so, how?
  • #2 - "With respect to the clai that the universe cae into being spontaneously from nothing, Professor Hawking writes, in the Wall Street Journal article: “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." What we need to ask Priofessor Hawking is: How is the word 'nothing' being used in these sentences?" Does he mean literally "nothing" in the sense of non-being? If he is using "nothing" in this metaphysically correct sense, then he needs to explain how "being" can arise from "non-being." Bill says: "If there is truly non-being, there is no quantum gravity; there's nothingness, and nothingness cannot be contrained because nothingness isn't something - it is non-being." Why, then, should a universe such as ours pop into existence from "nothing?" Why not "root bear," or "Beethoven?" If Hawking is using "nothing" in this philosopically correct sense, then his statement "the laws of gravity and quantum theory allow universes to appear" is, on the face of it, self-contradictory. Hawking must be claiming that there is some sort of "quantum state" exists, out of which our universe came. If so, then Hawking is using the word "nothing" to refer to this quantum state. But then there is "something," and Hawking has not explained the origin of the universe from "nothng."
  • Hawking writes: "Our universe seems to be one of many, each with different laws. That multiverse idea is not a notion invented to account for the miracle of fine tuning. It is a consequence predicted by many theories in modern cosmology. If it is true it reduces the strong anthropic principle to the weak one, putting the fine tunings of physical law on the same footing as the environmental factors, for it means that our cosmic habitat—now the entire observable universe—is just one of many." But it's not enough to siply posit the many-worlds hypothesis. What reasons are there to think that the many-worlds hypothesis is a better hypothesis than a single cosmic Designer? Craig asks: "In particular, what mechanism is there that explains the many-worlds hypothesis; what mechanism brings these many worlds into being? When we identify that mechanism, we need to ask is it fine-tuned as well?" This is Q#3 - If this mechanism that explains the many worlds hypothesis is itself fine-tuned, then fine-tuning has not benn explained, it's just been pushed back a notch.   
  • Q#4 - "We also need to ask Professor Hawking the question: What evidence is there that these many worlds, if they exist, are random in their constants and quantities? If the constants and quantities are just repetitive in these many worlds, then they do nothing to explain the fine-tuning of the universe." "What reason is there to think that these constants and quanitites are randomly ordered across the many worlds? And why should we think that these worlds are infinite in number rather than finite in number?"
  • Q#5 - How does Hawking respond to Roger Penrose's objection to the many-worlds hypothesis? Penrose, a colleague of Hawking, says that "if we are just a random member of a world ensemble, then it is incomprehensibly ore more probable that we should be observing a much different universe than the one we in fact observe. Therefore our observations make it overwhelmingly more probable that there is no world ensemble... Penrose argues that this appeal to "many worlds" and the anthropic principle is "worse than useless" in explaining the fine-tuning of the universe." We should ask, how does Hawking respond to Penrose's objections to the many worlds hypothesis as an explanation of the universe's fine-tuning?
(I'm expecting my copy of GD to arrive today!)