Review Roundup of Stephen Hawking's Grand Design

A skeptical reviewer says that Hawking overreached with his conclusions.

From the Economist (Full Review) :

The main novelty in “The Grand Design” is the authors’ application of a way of interpreting quantum mechanics, derived from the ideas of the late Richard Feynman, to the universe as a whole. According to this way of thinking, “the universe does not have just a single existence or history, but rather every possible version of the universe exists simultaneously.” The authors also assert that the world’s past did not unfold of its own accord, but that “we create history by our observation, rather than history creating us.” They say that these surprising ideas have passed every experimental test to which they have been put, but that is misleading in a way that is unfortunately typical of the authors. It is the bare bones of quantum mechanics that have proved to be consistent with what is presently known of the subatomic world. The authors’ interpretations and extrapolations of it have not been subjected to any decisive tests, and it is not clear that they ever could be.

It takes a lot of faith to embrace M-theory as the ultimate explanation on how this universe came into existence.

From the Observer (Full Review) :

"Our universe and its laws appear to have a design that both is tailor-made to support us and, if we are to exist, leaves little room for alternation," they state. "That is not easily explained, and raises the natural question of why it is that way." The answer, the authors say, lies with M-theory. (The M apparently stands for "master, miracle, or mystery". The authors are unsure which.) The vital point is that M-theory allows for the existence of 11 dimensions of spacetime that contains not just vibrating strings of matter but also "point particles, two-dimensional membranes, three-dimensional blobs and other objects that are more difficult to picture." Simple, really.



    Crucially the laws of M-theory allow for an unimaginably large number of different universes. Thus we exist because the laws of our particular universe just happen to be tuned to the exact parameters that permit the existence of hydrogen, oxygen, carbon and other key atoms and which also generate laws that allow these entities to interact in ways that build up complex chemical combinations. Other universes are not so lucky.

    M-theory is the unified theory of physics that Einstein was hoping to find, state the authors, and if it is confirmed by observation, it will be the successful conclusion to a search that was begun by the ancient Greeks when they started to puzzle about the nature of reality. "We will have found the grand design."

Since when did speculative become reasonable? I wouldn't conclude at this point that we can eliminate a divine cause for the existence of the universe.

From the Wall Street Journal (Full Review) :

Messrs. Hawking and Mlodinow trace the logic of quantum mechanics, general relativity and superstring theory, showing how a variety of existing universes isn't merely possible but arguably natural. In string theory, space inevitably has extra curled-up dimensions that we can't see. But there are many ways for dimensions to curl up, and each of them leads to different apparent "laws of physics." Then there's the idea of inflation, which predicts that an extremely tiny region of space can blow up into a universe-sized domain. Modern cosmologists believe that inflation, once it starts, can keep going forever, continually creating new "pocket universes" with different conditions in each one.



This is a picture that has been put together by a number of theoretical physicists over the past couple of decades, although it remains speculative. Mr. Hawking's own major contributions have involved the spontaneous creation of the universe "from nothing." The basic idea comes straight from conventional quantum mechanics: A particle does not have some perfectly well-defined position but rather lives in a superposition of many possible positions. As for particles, the logic goes, so for the entire universe. It exists in a superposition of many possible states, and among those states is utter nothingness. The laws of quantum cosmology purport to show how nothingness can evolve into the universe we see today. Speculative, yes; crazy, not necessarily.

This reviewer, who is clearly also an agnostic, does not buy Hawking's arguments.

From the New Scientist (Full Review) :

M-theory in either sense is far from complete. But that doesn't stop the authors from asserting that it explains the mysteries of existence: why there is something rather than nothing, why this set of laws and not another, and why we exist at all. According to Hawking, enough is known about M-theory to see that God is not needed to answer these questions. Instead, string theory points to the existence of a multiverse, and this multiverse coupled with anthropic reasoning will suffice. Personally, I am doubtful.

Athiests argue that since God is not observable and predictable, then his existence cannot be proven by scientific means. It is ironic that this reviewer applies similar sentiments to a cosmological theory that purports to be able to remove God in any discussions about the origins of the universe.

From The National (Full Review)

All this is merely ingenious sleight of hand, unless it can somehow be tested scientifically. That’s the problem. The other universes in the “multiverse” are inaccessible by definition, and the conditions that gave rise to them existed only in the first instants of the Big Bang. Even the Large Hadron Collider at CERN in Geneva can’t cook up enough energy in particle collisions to get close to such a primordial state.

Notoriously, this means that ideas such as M-theory which claim to offer Theories of Everything are very far from being experimentally testable, and thus empirically falsifiable. To some this prevents them from being truly scientific. Such attempts to develop “fundamental” theories are nonetheless valid and valuable, but they suffer a certain misconceived grandiosity, since one cannot simply unfold from them all of the world as we know it. For one thing, if Hawking is right that M-theory offers all possible universes, in effect it predicts nothing about our own. But in any case, the nature we encounter is both contingent and emergent: no Theory of Everything will ever predict, say, the earthworm, the human genome or the formation of the Himalayas. That is why many scientists sympathise with the suggestion of the American biophysicist George Oster that, rather than a Theory of Everything, it’s better to have a Theory of Something.