[CraigS]

I’ve been puzzling over this review of the Stephen Hawking/Leonard Mlodinow book: “Grand Design”, by fellow physics author John W Moffat. (He’s a member of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, and professor emeritus at the University of Toronto).

Moffat makes some good points in his review, and I find myself agreeing with him on many issues. For example he says:

It is important to the argument of the book – which leads eventually to more exotic models such as M-theory and the multiverse – that readers accept the premise of model-dependent realism. However, the history of science shows that the premise of one model being as good and useful as another is not always correct. Paradigms shift because a new model not only fits the current observational data as well as (or better than) an older model, but also makes predictions that fit new data that cannot be explained by the older model. Hawking and Mlodinow's assertion that "there is no picture, or theory-independent concept of reality", thus flies in the face of one of the basic tenets of the scientific method.

In this, he’s pointing out a logical flaw in the line of argument of the book, but the point underlined, is a great one. One of the biggest problems I think mainstream science is wrestling with, is just this issue. The mass-media does shape our reality, by citing scientific theory as real, but we don’t necessarily have to make it our reality. (It certainly isn’t mine). Its not science that does this ... its people’s interpretation, and the media’s presentation of it. Ie: science is ‘believed’, becomes ‘true’, 'faith' develops and then morphs into just another ‘religion’.

Have Hawking and Mlodinow fallen for this as well ?
(This is the aspect, and question, I pose in the title of this thread .. )

Moffat concludes ..

Near the end of the book, the authors claim that for a theory of quantum gravity to predict finite quantities, it must possess supersymmetry between the forces and matter.
They go on to say that since M-theory is the most general supersymmetric theory of gravity, it is the only candidate for a complete theory of the universe. Since there is no other consistent model, then we must be part of the universe described by M-theory.
Early in the book, the authors state that an acceptable model of nature must agree with experimental data and make predictions that can be tested. However, none of the claims about their "grand design" – or M-theory or the multiverse – fulfills these demands. This makes the final claim of the book – "If the theory is confirmed by observation, it will be the successful conclusion of a search going back 3000 years" – mere hyperbole. With The Grand Design, Hawking has again, as in his inaugural Lucasian Professor speech, made excessive claims for the future of physics, which as before remain to be substantiated.

Pretty critical analysis, but perfectly valid, I feel.

So, like it or not, because there is no other consistent model, we must be part of the universe described by M-Theory. A leap of faith ?

I wonder ..

The only M-Theory test I’ve ever seen hinted at, was described here.

And present-day tests for String Theory, (which would also be of significance in M-Theory), amount to entanglement and black hole mathematical commonality, thus enabling a string theory test to evolve and ..
the results of tests of ultra-chilled sticky gas may allow experimental tests of String theory in the future.

An interesting review (and thought provoking book).

Comments welcome.

Cheers