Yes, recall Hawking writing something about having shown how God was unnecessary because the universe had a beginning but was still "eternal" or something. Can someone please explain this?
It's what Hawking describes as the "no boundary" condition to the universe. It essentially bypasses the Big Bang itself while still allowing for the expansion and all of the expansion's effects that the Big Bang predicts. If I remember correctly, the mathematics involves the use of "imaginary time" which is the dimension of time modelled by imaginary numbers (numbers derived from the square-roots of negative numbers). He went into it in one of his previous books and
The Grand Design mentions it in much briefer fashion. Not quite as bizarre as it sounds, given that imaginary numbers are very useful in quantum mechanics, a theory that works spectacularly well in practical terms.
I've just finished
The Grand Design and will post my thoughts later. For now, I'll just note that I pretty much agree with all the viewpoints posted so far.
-- Updated Sun Jun 10, 2012 12:50 pm to add the following --
Okay, I'll review the book by answering Scott's post:
I realized this turned out to be an interesting pick when right at the beginning of the book the author's write that philosophy is dead. What do you make of that? I disagree in general, but I think the statement has some accuracy in describing why more laymen are interested in theoretical physics and science than philosophy in that the former is providing them with answers and especially more concrete answers than philosophy even for traditionally philosophical questions. Ironically, I think the author's disprove via demonstration their own assertion of the death of philosophy by being in part philosophical when writing their book. Indeed, I think philosophy takes what we learn from science and then expands on it -- contemplates it -- in ways science cannot.
I agree. The fact that Hawking makes the statement categorically on page 1, and has no further comment, is richly ironic given the arguments of the book owe much of their coherence to specific philosophical ways of looking at science. Yet the point has validity in that philosophy is no longer taught in any general curriculum so science ends up appearing authoritative since laymen are often unaware of the roots and grounding for science.
What do you think of model-dependent realism as described by the authors? I think it is very useful for understanding the use and inherent limitations of science, thus creating the perfect philosophical framework in which to discuss and learn about the discoveries of science.
Model-dependent realism is the most valuable lesson this book has to teach, in my opinion. Unfortunately, his arguments for it are weakened by being very one-sided. He should have devoted a page to its antithesis--an objective realism--and knocked some holes in it to show how model-dependent realism stands up where objective realism fails.
Regarding the name "model-dependent realism," my philosophical puritanism chafes at the use of the word "realism" in this label. Traditionally realism means something very specific in philosophy and most saliently in the philosophy of science. To preface it with the words "model-dependent" strikes me as just short of an oxymoron. Hawking states categorically in Chapter 3: "Model-dependent realism short-circuits...argument and discussion between the realist and anti-realist schools of thought."
No it doesn't! I want to scream.
Model-dependent realism is clearly a form of anti-realism! Yet I end up only sighing instead of screaming, because Hawking does his job of explaining exactly what he means, and with his caveats, it makes sense. Unfortunately by not acknowledging the philosophical fact that it is anti-realism, he ends up confusing the reader later on into thinking Hawking's conclusions must be ontologically real.
In previous books, Hawking had called himself a Positivist, so now with his "philosophy is dead" declaration I kept an eye out for any potential hypocrisy. Sure enough, in Chapter 3, Hawking argues that model-dependent realism "solves" the meaning of existence by avoiding it. The example he uses to showcase this is instead nothing but a showcase for pure Positivist hubris, utterly failing to support Hawking's claim, with Hawking apparently unable to see this failure through his unwitting Positivist-colored glasses. Hawking's editor owed it to the reader to get Hawking to just pull the entire paragraph which serves no purpose.
...I am not expert, but I have a lot of skepticism about the uncertainty principle and the effect of observation in quantum mechanics--because I think think in public these are spun with specific interpretations of quantum mechanics as opposed to just the science itself. I wish the author's would have given more detail to explain the details of this, particularly since the authors seemed certain these were evidence of literal superposition and randomness rather than more traditional effects of interactive measurement.
This has always been my biggest complaint about Hawking's books, and it is in full evidence here: Hawking's credulity about what he presents. What I mean is that Hawking is writing this book for laypeople so the need to abstract mathematically-formalized theory into non-mathematical verbal illustrations that non-scientists can understand is obviously necessary, and to accomplish it means drastically simplifying concepts so that in many cases, only the gist of the theory remains. This is unavoidable if we laypeople are to appreciate physics. But Hawking makes very little effort to remind us that his statements are bound to a model: an ad hoc model whose legitimacy is in its utility, not its realism. By failing to qualify his statements, the reader ends up believing that the model's components are ontologically real. This is unfortunate.
What do you think of the author's comments on M-Theory? I think M-Thoery has a lot farther to go before it can be the so-called theory of everything, i.e. the theory that unites general relativity with quantum mechanics, than what the authors let on. I can see in terms of book-writing it may have been wiser to leave off on a optimistic note or perhaps there is some other reason for such optimism, but I would have preferred a fairer critique of M-Theory with emphasis not only on its pros and potential but on its cons and current failings.
I agree. I am personally disappointed the Hawking has bought into M-theory. However, I'm not surprised. In a way, his sellout to M-theory is the best example of his own commitment to a philosophy of "model-dependent realism." My disappointment lies in how Hawking feels he can cover his bases by letting the reader know that M-theory is still unproven, while rationalizing its utility. That's not enough. He owes it to the reader to be intellectually honest and tell them that M-theory is purely speculative despite the elegance of its mathematics.
In effect, M-theory represents the "down side" of model-dependent realism: the temptation to merely support the model instead of seeing the model's flaws as the driving force for finding evermore comprehensive models, preferably ones that can be tested (unlike M-theory). If we abandon science's testability requirement, as M-theorists all seem to want us to do, then we truly will have created postmodern science as Grendal suggested. I don't see any evidence that this would be a good thing.
Anyway what do you think?
I am also personally disappointed to see Hawking has bought into anthropic reasoning, thoroughly overrating it as a tool for scientific inquiry. He spends a surprisingly large number of pages defending anthropic reasoning, providing numerous examples, while merely iterating its tenets instead of providing any new insights. I had no trouble at all countering everyone of his claims of significance for anthropic reasoning to my personal satisfaction without even having to pause for contemplation.
In the final analysis, Hawking has used an anti-realist rationale for scientific inquiry as a basis for interpreting the combination of M-Theory with the Anthropic Principle to be a justification for believing in Multiverse theory. To me, he only succeeds in demonstrating that Multiverse theory is a sufficient condition for current cosmological theory, not a necessary condition, while at the same time failing the testability requirements of traditional empirical science.