By Deepak Chopra and Menas Kafatos, Fletcher Jones Professor of Computational Physics, Dean College of Science ,Chapman University
In the first part of our review of The Grand Design we offered a response from the viewpoint of the general reader. But given the scientific esteem of Stephen Hawking and Leonard Mlodinow, we wanted to address their theory of creation, known as M-theory, in more technical terms. This is such an important debate that the interested reader will find much to ponder.
The authors of The Grand Design have tackled an age-old subject -- the origins of the cosmos -- which more recently became a public controversy with the whole intelligent design debate. They go even farther, claiming that M-theory will bring to an end the quest for a unified theory of physics. (They concede that "no one seems to know what the "M" stands for, but it may be "master", "miracle", or "mystery,"' rather a letdown when you propose to explain all that exists.) These are bold goals were they to be realized -- M-theory would constitute a major revolution in humanity's search for the meaning of cosmos (if any) and our role in it. However, it is our view that the book doesn't add enough to resolve these grander issues. The basic reason is that Hawking and Mlodinow place their faith in physics to resolve ancient metaphysical questions, such as the need for a Creator, the existence of free will, and the relationship between mind and matter. But aside from that, what can be said about the science presented in The Grand Design?
Let's look first at the foundation of their thesis. Hawking and Mlodinow implicitly accept the External Reality Hypothesis (ERH), which, according to Max Tegmark of M.I.T., states that there exists an external physical reality, completely independent of us humans. This is in reality a metaphysical statement since it relates to the nature of existence (being). The adherents of the Copenhagen Interpretation of quantum mechanics would reject the ERH on the grounds that there is no reality without observation. In other words, a human observer is woven into the fabric of science and perhaps of anything we can know about existence. We are not like children with our noses pressed against a bake shop window staring at what is behind the glass. We are part of the cosmic scenery, inseparable from what we see.
Quantum physics makes us focus not just on data but also on the way that we study the physical world, an interaction that forms an undivided whole. Actually, Hawking and Mlodinow seem to favor this view as well (as do most quantum physicists). They state, "The universe itself has no single history (our note, following Richard Feynman's sum over histories approach in quantum field theory) nor even an independent existence." This adheres to what John Wheeler of Princeton termed the role of observer-participant, the foundation of the Copenhagen interpretation. At the same time, however, The Grand Design supposes the independent existence of reality, or being. What is the role of observation, then? After decades of debate involving the greatest quantum physicists from Einstein on, the verdict is in: quantum mechanics is incompatible with local, realistic theories. Non-locality reigns supreme, and it holds that quantum events are connected across the cosmos, events that are realized through an observer. Space and time create local events, but non-locality defies our common sense notion that anything can be isolated in one place at a given time. The universe is stranger than that: if you tickle it here, it laughs over there.
Non-locality, as many physicists hold, may be the most profound discovery of modern physics, more so than M-theory. Non-locality is testable and has been tested in the laboratory; M-theory remains a speculation of cosmologists. It would have been good if Hawking and Mlodinow told us where they stand with respect to this issue. They do not say much about it although non-local reality is implied if one accepts many universes, as they do. What is the connection of non-locality to M-theory? For them to be silent on the most fundamental aspect of the quantum world, in a theory that purports to be the theory of everything, is a serious shortcoming.
In modern quantum theory, the building blocks of Nature are not static "things", like pebbles or little billiard balls, but dynamic, dancing interactions of possibility waves. If that is correct, as it is generally agreed it is, then one can assert a transcendent realm. To call something a possibility wave is to call it a "potential." A potential does not exist in space-time, it is actually the source of space-time. As such, the infinite transcendent presence from which space-time and all waves arise is the immeasurable potential of all that was, is and will be. As such, these waves of possibility allow an infinitely complex set of actualities to emerge. Hawking and Mlodinow remain ambiguous on an issue that could be the very crux of the matter.
Many physicists are puzzled by the value of the so-called "constants" of nature and the fine tuning required (not just in cosmology) to have the present universe as it is. Staggering fine tuning from 1 part in 10 to the power 50 are required to account for the current, observable universe, such as the homogeneity of the universe (i.e. having a more or less constant density at early times) and the isotropy (i.e. looking the same in all directions, as for example indicated by the cosmic background radiation), as well as the cosmological constant, which was formulated and then rejected by Einstein but now is back in vogue.
Hawking and Mlodinow, in keeping with the vast majority of physicists, want to preserve the constancy of physical laws as well as the fundamental principle that randomness rather than design prevails in Nature. Cosmologists have thus devised the multiverse theory that Hawking and Mlodinow favor. It proposes other universes to explain why our universe came to be perfectly fine-tuned for conscious life to exist. The reasoning goes like this: if there were a very, very large number of different physical laws and/or physical constants in all these universes, some of them would have laws that were suitable for stars, planets and life developing on these planets to exist.
Our particular universe would then seem unique when in fact it wasn't. Human life would still be random, even though fine-tuning makes it mathematically improbable -- to say the least -- that random swirling gases gave rise to life with such precision. But if you can afford to throw out billions upon billions of universes, improbabilities don't matter. On the other side is the theory that human beings cannot help but be the focus and end result of cosmic evolution. This theory is based on the so-called anthropic principle, which comes in two varieties, the weak and the strong. The weak anthropic principle holds that conscious beings (us) exist only in those universes which are finely-tuned for such conscious existence. The strong anthropic principle, on the other hand, "suggests that the fact that we exist imposes constraints not just on our environment (e.g. the existence of the right stable planetary orbits around a star) but on the possible form and content of the laws of nature themselves."
One would thus get around the question of fine tuning, which points strongly to intelligent design, by having a vast number of universes, most of them "still-born" (i.e. not supporting life and consciousness) but with a few allowing life to develop, including the cosmos we live in. Hawking and Mlodinow accept the strong anthropic principle but only in the context of the multiverse. We will return to this issue later.
The Grand Design also makes a bold and we believe unjustifiable claim that M-theory puts an end to the quest for a unified field theory, that is, a complete explanation for all physical processes. Reducing all the laws of nature to a single mathematical framework is the holy grail of physics. M-theory resulted from several decades of advances in unifying the weak and strong forces, leaving only gravity to be included. What Hawking and Mlodinow offer is essentially a multi-dimensional extension of string theory, which is also a candidate for unifying particle interactions. It adopts 11 or perhaps as many as 26 dimensions to comprise the multiverse. Objects are confined to that universe but may be able to interact with other universes via gravity, a force which is not restricted to a particular universe.
It is this property of gravity, according to the authors, which necessitates the spontaneous creation of multitude of universes. Gravity has no physical attributes; it is abstract and impalpable. Thus it becomes the transcendent creator, operating out of a void. "M-theory predicts that a great many universe were created out of nothing." Moreover, since gravity exists beyond all the billions of universes that spring up, creation can't be tied down to any single formulation: "there seems to be no simple mathematical model or theory that can describe every aspect of the universe. Instead there seems to be the network of theories called M-theory (or what we may term a "theory of theories"). Each theory in the M-theory network is good at describing phenomena within a certain range. Whenever their ranges overlap, the various theories in the network agree, so they can be said to be parts of the same theory."
The ensembles of universes are generically known as the multiverse (but there are actually different types of multiverses that scientists are exploring). "M-theory has solutions that allow for many different internal spaces, perhaps as many as 10 to the power of 500, which means it allows for 10 to the power of 500 different universes, each with its own laws. To get an idea of how many that is think about this. If some being could analyze the laws predicted for each of those universes in just one millisecond and had started working on it at the big bang, at present that being would have studied just 10 to the power of 20 of them."
This seems like sleight of hand, however. Their theory of everything posits that there is actually no theory of everything. Instead, we have short-range explanations, each plausibly woven into the other. Armed with M-theory, Hawking and Mlodinow can now challenge the concept of creation by design:
... creation does not require the intervention of a supernatural being or god. Rather, these multiple universes arise from physical law. They are a prediction of science. Each universe has many possible histories and many possible states at later times, that is, at times like the present, long after their creation. Most of these states will be quite unlike the universe we observe, and quite unsuitable for the existence of any form of life. Only a few would allow creatures like us to exist. Thus our presence selects out from this vast array only those universes only those universes that are compatible with our existence. Although we are puny and insignificant on the scale of the cosmos, this makes us in a sense lords of creation.
For hard-nose scientists of the kind they claim to be, this is metaphysics to the nth degree. We would agree that human beings are lords of creation, in the context of quantum participatory universe. But the statement that "our presence selects...compatible with our existence" is vague and has no formal mathematics, which is inconsistent with the author's stated goal. They are talking about being, all the time.
Let's look more closely at the concept of the multiverse. In fact, different classes of multiverses exist. A great taxonomy of universes (forming different types of multiverses) has been provided by Max Tegmark. Each one successively encompasses the previous types: Level I, would be the multiverse containing universes with all possible initial conditions, but still similar to ours, all with the same physical laws and the same physical constants (such as the speed of light). This prediction follows from the theory of chaotic inflation. These universes would be located beyond the horizon of our own universe. Most of them would be different in size but some, similar to ours, would be far, far, far away, more than a googolplex meters away (or 10 to the power of 10 to the power of 100!). Level II, are universes with different physical constants, or "bubble universes." They occur in the chaotic inflation theory, and they are embryonic level I multiverses.
Cosmologists estimate their number to be 10 to the power 10 to the power 10 to the power 7, a number that for all practical purposes is infinite, we cannot even expand it in writing! Different bubbles would experience spontaneous symmetry breaking resulting in myriads of universe with different constants, i.e. different laws of nature.
Level III type of multiverse follows the many worlds interpretation (MWI) of quantum mechanics first formulated by Hugh Everett and others, among them Wheeler. In quantum mechanics, certain observations cannot be predicted with absolute certainty; there is a range of possible observations, each with a different probability. According to the MWI, each of these possible observations corresponds to a different outcome in a single universe, but each outcome splits and cannot communicate with the others.
As Tegmark remarks, Level I and Level III are somewhat similar, although one resides in regular space-time, while Level III reside in probability space. The MWI comes with so much metaphysical baggage that Wheeler himself abandoned it. The problem, pointed out in the Conscious Universe by one of us, is that MWI assumes the absolute reality of the wave function which is used to describe the state of a quantum mechanics system. We should keep this in mind since MWI, although not the same as the M-theory with its multiverses, is closely related to it. Related to M-theory is Richard Feynman's multiple histories interpretation of quantum mechanics, which Hawking and Mlodinow embrace.
Level IV is the one that Hawking and Mlodinow adopt (although they did not discuss the other types). Having been developed by Tegmark, Level IV considers real all universes that are defined by specific mathematical structures, including universes that have different physical laws from ours. In this most general case, any Theory of Everything must have a mathematical structure. Therefore, mathematics is what counts in the end: multitudes of universes exist because different mathematics exist. We may even assume that this is the case. But then what is the origin of mathematics?
The fallacy here is that Hawking, Mlodinow, and many other theorists assume that mathematics exists outside of the mind that creates theories. A profound metaphysical assumption is being swept under the rug. For example, is the Hilbert space, which allows the formalism of quantum mechanics to work, real in itself? If the answer is yes, then we should, e.g., all follow Plato as this was precisely his view, namely that mathematics resides in a transcendent realm. But then there are only two choices: a) Mathematics and us, the minds who develop mathematics, are in a transcendent realm. If not, then b) Mathematics is an external agent, operating independently of human observers. How is that different from an external God operating outside of human observers?
We prefer the former view, and upon serious consideration, we believe this view may actually be more compatible with science. The Copenhagen school would insist that we should always consider the mathematical formalism as the means to interact with nature, the language we use to communicate with nature. We are part of the whole structure, or more correct the whole process, the mathematics, the physical system or universe, and us.
What we need is a dialogue between science and metaphysics, recognizing both as valid but complementary aspects of one reality. To refute one or try to merge both goes against the efforts of dialogue, the only way out of many problems. By the same token, metaphysics cannot substitute for physics. It cannot work from the premise that there is a creator God, for example, and then force science to conform to it. This is what the proponents of intelligent design attempt to do. The debate will go on, and few people will have their minds changed by this book alone. Perhaps, irrespective of the metaphysical arguments it makes against any need for a Creator, The Grand Design will help the argument to be made more cogent. We will be walking the shadowy line between physics and metaphysics for a long time to come.
(To be cont.)