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The Comprehensible Cosmos: Where Do the Laws of Physics Come From?

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Review of Victor Stenger's Comprehensible Cosmos

January 24, 2007

Where do the laws of physics come from? The Power of P.O.V.I.

In this admirable new book, physics professor Victor Stenger once again exhibits his notable ability to convey complex ideas of physics with simplicity and elegance, while not sacrificing mathematical rigor and detail. Moreover, the book offers a "big-picture" perspective that will appeal to both physicists and non-physicists. However, although not required, a basic familiarity with physics and a mathematical background will greatly enhance readers' appreciation and comprehension of the book, particularly concerning the helpful mathematical supplements provided at the end.

Here Stenger takes on "ultimate" questions, such as, Where do the laws of physics come from? and Why is there something rather than nothing?- answers to which are commonly believed to be found exclusively within the province of theological and philosophical discourse and to be inherently beyond the reach of empirical and theoretical science. Stenger argues that the extraordinary empirical success of our current models of physics, though still incomplete and provisional, gives us good grounds to assume that they are on the right track: the cosmos is indeed comprehensible, and our current physical models provide a description of nature that is likely to faithfully reflect aspects of a reality that exists independently of our thoughts and particular physical models.

Stenger argues that, contrary to some popular views, the so-called "laws of physics", such as the great conservations laws, are not restrictions on the behavior of matter imposed by an external agent or by a world of abstract Platonic mathematical forms. Rather they arise from the self-imposed requirement that physicists' descriptions of nature be independent of the particular point-of-view of observers- that they be point-of-view invariant. In order to ensure universal applicability and to describe reality as objectively as possible, physicists aim to construct mathematical models that describe nature in such a way that these descriptions do not depend on the particular point of view or reference frame of observers. For instance, the law of conservation of energy is a manifestation of time-translation invariance. A description of nature that does not depend upon the absolute time at which observations are made will automatically entail the conservation of a quantity called `energy'. Similarly, the law of conservation of momentum naturally arises from the requirement that physicists' descriptions of nature are space-translation invariant- that they do not depend upon any particular point in space.

Stenger's account builds upon the work of mathematician Emmy Noether, who proved that certain mathematical quantities called the generators of continuous space-time transformations are conserved when those transformations leave the system unchanged. Hence, the great conservation laws are consequences of point-of-view invariance and thus are reflections of the symmetries of space and time. As Stenger puts it: "If you wish to build a model using space and time as a framework, and you formulate that model so as to be space-time symmetric, then that model will automatically contain what are usually regarded as the three most important "laws" of physics, the three conservation principles". Stenger further demonstrates how Newtonian mechanics, quantum mechanics, and special and general relativity also arise naturally from the point-of-view invariance and symmetries of our physical models.

In addition to showing the intimate connection between the laws of physics and the symmetries of space and time, Stenger argues that features of our complex lower energy universe may be accounted for by the spontaneous breaking of symmetries that were present during the higher energy state of the big bang. Our universe is akin to a less symmetric snowflake that froze out of a more symmetric sphere of water vapor. Stenger discusses the possibility that our universe arose via a well-understood process of quantum tunneling from a highly symmetric void, empty of energy, particles, space, and time- a featureless state essentially equivalent to `nothing' . Since the void also exhibits space-time symmetries, the laws of physics are ultimately derived from the symmetries of the void. Indeed, Stenger argues that the laws of physics are not really laws at all, in the usual sense of the term. On the contrary, they are reflections of the absence of laws- they are what Stenger refers to as "lawless laws". Other aspects of nature, such as the apparent indeterminism of quantum mechanics can be accounted for by an element of randomness in the universe (which, Stenger notes, is itself a manifestation of invariance). Ultimately then, symmetry and randomness lie at the bedrock of reality. Hence, the universe is not only comprehensible, but may have arisen in the simplest way possible: randomly and spontaneously from a highly symmetric void, that is, from a state essentially indistinguishable from `nothing'. But then why is there something rather than nothing? Indeed, if the universe came from a void, then why did it not remain as a void? The answer Stenger offers, and which gains support from the work of other physicists, is that a symmetric void is unstable- hence there had to be something. Our universe is simply a different phase of `nothing', just as ice and steam are different phases of water.

There are plenty more topics discussed in this original and insightful book, including particle physics, cosmology, and thermodynamics, which are beyond the scope of this review. Perhaps some readers might complain that Stenger is too cautious in his lack of commitment to particular physical models of reality. At times he suggests that "scientific criteria cannot distinguish between viable metaphysical schemes" and that space and time are useful inventions that cannot be proven to exist. While this may be the case, this suggestion may be seen to weaken his thesis that the cosmos is comprehensible and that physics is not just another cultural narrative. On the other hand, Stenger emphasizes throughout that our physical models ultimately must be constrained by and consistent with empirical observations. Indeed, the relentless testing of the observational consequences of our physical models is what distinguishes physics from fiction. Thus, our physical models, while human inventions, are not just arbitrary cultural constructs. To the extent that they succeed in describing nature and surviving risky empirical tests, they likely represent aspects of an underlying reality independent of our specific models. Moreover, Stenger comments on how a particulate model of reality characterized by "atoms and void", which he explicitly favors, displays some virtues over a model characterized by waves, fields, and other "Platonic" mathematical constructs. If indeed physics does have implications for metaphysics, then physics might someday provide compelling empirical or theoretical reasons to prefer one hitherto observationally equivalent metaphysical model over another. In any case, readers will appreciate the elegance and simplicity of Stenger's expository style, which are paralleled by the elegant simplicity of the scenario he has described for the origin of the universe and of the laws of physics.

Yonatan Fishman, PhD
Department of Neurology
Albert Einstein College of Medicine

This small (320 pages of text) is, in essence, an epitome of the basic physics of our day. It covers space and time, classical and quantum mechanics in their fundamental form, relativity, thermodynamics, cosmology, particle physics and their interactions. Each topic is treated in rough terms in a main chapter and with precision in a mathematical appendix. What makes this work unique (and not just another textbook of physics) is an attempt to systematize the material under a few very basic principles. Most important of these is the generalized form of invariance called "point of view invariance" by the author, though other postulates are introduced as necessary. My only quibbles are: (a) these principles could be summarized somewhere, (b) the debates discussed in the book over instrumentalism, realism, etc. are too perfunctorally discussed. However as this is not a philosophy of science book on those topics, the oversights can be forgiven. Finally, (c) as a non physicist, I do find myself wondering which approximations are good ones and which not. Sometimes, to achieve equality of two terms, etc. Stenger makes mathematical approximations. This is indispensible; instead what could have been useful is some discussion of where the assumptions so made break down. This is done in some places (e.g. in the discussion of the connection between Newtonian and Einsteinian understandings of motion) but not others, so the flaw, such as it is, is not ubquitous.

Other merits of the book include a clear writing style, bibliographic suggestions for further reading, helpful diagrams and some historical perspective by including years of death for various key physicists.

This is the third book from Professor Stenger that I've read. In my mind, he's certainly the "Richard Dawkins" of general-audience physics books.

I won't repeat too much of the content of other reviewers of this book, but rather just touch on a couple areas that I found particularly interesting:

I enjoyed how the professor stresses the simplicity of nature. For example, he shows in this book how almost all of physics comes from generalized gauge invariance, which he calls "point-of-view invariance." By the end of the book, we're shown how the "laws" of physics are not really laws at all. In the professor's well-expressed view, our traditional physical laws, in fact, are not somehow built into the fabric of the universe or handed down from above, but rather emerge from natural symmetries of a void.

On a related note, I also enjoyed how he went into some detail regarding how this simple view of nature (what he calls "Atoms and the Void") is at odds against the (secular) Platonic worldview. I believe he does a fair job explaining both views and why a simpler view of nature is preferable.

Anyways, it's hard to say enough about this book. Pick up a copy and enjoy!

After a long career in experimental particle physics, Victor Stenger presents a philosophical view of physics that steers the boundary between instrumentatlism and naive realism. He provides a wonderfully unified view of physics based on a kind of generalized symmetry he calls point-of-view-invariance. It's a requirement not on nature but on physicists to make their theories objective. It goes suprisingly far in describing why the theories of physics are what they are. It also explains why the universe as described by physics is comprehensible.

The main part of the book explains physics without equations at a level accesible to most people. The appendices are more mathematical, but they will be appreciated by engineers, scientists, and others with a more technical education. It's not a text book and it's not the place to learn these theories, but it would be a great Christmas present for any upper division or graduate physics student.

I am a non-scientist who reads a lot of science. Dr. Stenger's book was brilliantly constructed and argued, digesting a century or two of progress in physics into a few core principles and their descendents. Unfortunately for me, the emphasis on mathematical arguments was not to my particular taste, and I admit to getting bogged down in the quantum mechanics particle soup. I prefer a more expository and less abstract style, as with Feynman's general interest books. Thus, this is not a book I would recommend sight unseen. I do not agree that the material will be accessible to most lay readers of science. I suggest skimming sections to see if it fits your style. For some, the book may be perfect, and I can well understand the very high ratings by some other reviewers.

The key concept was how much derives from so little, in particular the point of view invariance. It almost sounds easy, like why didn't people think of these brilliant theories before? That is an amazing insight, really, compared to physical models or the interaction of matter and energy that comes more naturally to humans.

Stenger gives gracious credit to Emily Noether, previously unknown to me, for the mathematical work used to derive many of his conclusions.

Stenger takes on many topics of interest, usually with brief explanations on fundamental ideas: how can something come from nothing, how can there be energy in a vacuum, why light is actually not a wave, laws vs. the absence of laws, the irrelevance of absolute time, and so on.

The mathematical appendix was largely over my head. Too many years removed, I'm afraid. Even where the details were unclear at my level, the mathematical summary was interesting, because it showed which of the principles had fairly basic mathematical foundations and which ones took more sophistication.

Professor Stenger's book draws a map for the non-scientist through the otherwise intimidating terrain of physics. His survey bypasses the winding streets and cul-de-sacs that bewilder strangers, thus emphasizing the major avenues and boulevards that carry visitors from Democritus past Galilei, Newton, Einstein, Feynman, Hawking, and other physics landmarks. These luminaries light Professor Stenger's path from the nothing that preceded everything to the universes on each side of the first moment. "Nothing" includes neither matter nor energy. He walks us from that nothing void to the everything that includes us, everything from the tiniest strange quark to the greatest discernable distance. He does this by introducing the idea of point of view invariance, the idea that the laws of physics should apply in all reference frames. That simplest of keys opens the way for comprehending the cosmos, even for us who once knew but no longer remember much of calculus and trigonometry. He writes simply and clearly, without requiring the reader to re-read sentences over and over to glean an arcane point. Finally, for those who want meatier explanations in the language of mathematics, he includes several addenda in which he derives with undergraduate mathematics the points he makes earlier in simpler English.

In the "The Comprehensible Cosmos" the reader is taken on tour of Newtonian Mechanics, Relativity, Quantum Mechanics, the standard model of particle physics and cosmology with the depth and clarity anyone familiar with Dr Stenger's earlier books has come to expect. Dr Stenger introduces a concept which he calls "point of view invariance" which neatly explains how science creates useable models that directly relate to the underlying objective reality of nature. In addition, Dr Stenger includes a detailed mathematical supplement for each chapter for those who desire a more in-depth understanding. This book will be an invaluable resource for anyone with an interest in understanding the models which Science uses to describe the Universe we live in.

It could be argued that the century of the 1900's from 1900 to 1999 was the century of physics. It began with the 250 year old ideas of Newton being challenged by certain experimental evidence. In earlier centuries you didn't dare claim anything was wrong, or could even possibly be wrong, with what Newton said.

Then came the invention of tensor calculus which Einstein used to extend Newtonian physics into the very small (photons of light) to the very large (galaxies). And once the changes started here came quantum mechanics, particle physics (saying that once thought basic building blocks like protons were made up of quarks), quantum electrodynamics, and then experimental evidence started to show even stranger things. To use Dr. Stenger's words, after the old fashioned things like matter are considered the rest of the universe is made up of 'Exotic Dark Matter,' and 'Even More Exotic Dark Energy.'

This book talks about all of these developments, and many more in a manner that makes it suitable for the lay person. To be sure, he does have some sections of a nature that if you want to see the math behind the concept, here it is.

It makes you wonder what Galileo would have thought after the church had locked him up for saying that the Earth went around the Sun rather than the Earth being the center of everything.

Then again, it makes you wonder if a biologist wouldn't say that it was a century of biology - with the invention of antibiotics, DNA, genetic manipulation, and more. And of course the church has moved its interest away from physics to areas like evolution.

This is a splendid book. Not exactly easy reading, but it will update you on virtually everything that happened in physics - so far. Meanwhile, the next century is waiting.

Professor Victor J. Stenger provides a fine survey of the status and science of physics in THE COMPREHENSIBLE COSMOS: WHERE DO THE LAWS OF PHYSICS COME FROM? Where exactly do the 'laws' revealed by math come from, and do they represent religious constraints on behavior built in by God or a governing body? These and other intriguing questions provide students of physics with challenging food for thought in a survey essential to college-level collections. Many a professor will wish to use it as a foundation for classroom discussion and debate extending the realm of scientific observation and discovery into the world of philosophical meaning.

For so long I was enamoured by writers such as Paul Davies and Martin Rees who were almost theological in their approach to the conclusions they drew from what they knew of the laws of physics. The fine-tuning "problem" even gave pause to skeptics of the ilk of Richard Dawkins. Victor Stenger is one of the most prominent of sober physicists who do not seem to crave a "congregation" of almost psuedo-religious fans of undergraduate physics students. Truly...physics professors who suggest/imply/middle on how the laws of physics imply this-or-that metaphysical scheme or this-or-that ontology conjure up images of clerics in need of sinners to minister to. It must be great for the ego to have people ask you what the meaning of life is...and think you really do have an insight because you can do tensor calculus on manifolds and solve differential equations most cannot.

Paul Davies has quipped that cosmologists and physicists are seen as the "new priests" with answers to ultimate questions. This is telling. Stenger goes against the grain and dismisses this notion that knowledge of the the laws of physics could give any deeper insight into questions about ultimate existence. I should say: I have much respect for Davies: the writer of so many popular science books that originally got me interested in these questions about "God, Life, the universe and Everything"...I was won over by the idea that physics gave us a glimpse of mystery akin to that suggested by mysticism. Skeptics and those who respect science quickly conclude that almost all contained within the teachings of the world's religions is (clearly) rubbish...but nonetheless many of us feel a sense of awe about the universe and the secrets science is uncovering. We use a variety of techniques to pander to this feeling. Some of us, among pursuing other methods of to uncover the deepest truths of reality turn to the writings of the most accomplished scientists of our age and find a book here or there by a renowned physicist like "The Mind of God", or "The Physics of Immortality" or...the list is "long and preposterous" to borrow a phrase from Sam Harris. A wide-eyed undergrad physics or philosophy student or a lay enthusiast is easily led down a psuedo-scientific trail towards pseudo-religious nonsense by (perhaps?) well meaning scientists posing as science-communicators. Davies' is typical of "that" kind of science writer. 99% excellent exposition of well-accepted science and sensible philosophy. But peppered within is just enough metaphysics...often mainly in the title...to suggest that physicists have observed more than just physical entities in their experiments. Or perhaps they have explained more than just the physical world with their theory. That 1% of rubbish speculation found in popular science...that loose language suggesting this-or-that metaphysical scheme (in Davies case...a 'design' or 'purpose' or 'providence' argument) is not justified. I used to just "feel" this was the case. Now, with Stenger behind me, I know I had a reason to be skeptical.

I was won over for a long time by the ideas hinted at by so many physicists who write popular science - that an understanding of the laws of physics suggests something deeper. Though we won't say what. But we'll talk about God and design and purpose all the while...all the while we say that we aren't exactly saying it implies God. But if YOU think it does...well...that's not inconsistent with what we say.

Stenger shows the physics doesn't suggest anything of the sort. It's all in the minds of certain physicists. Or, insofar as they understand Stenger's point...they know what sells books. A title with "God" in it rather than a blurb on the back suggesting that the book argues that everything we know about physics suggests nothing more than that the universe can be understood in terms well-established physics without recourse to anything supernatural. Much of popular physics writing beyond Stenger seems to be wishful thinking after reading "The Comprehensible Cosmos". Or worse the writings and words of some otherwise skeptical physical scientists might suggest a psychological tendency to appeal to the science-groupies that will fawn over their speculations that perhaps what-we-know or what-we-think-we-know about physics points to some ultimate meaning.

Many years ago I lost faith in priests and bishops...I thought began to think in my first or second year of undergrad physics that the best physicists would have answers to the deepest questions. And they did of course. They were entitled to claim a deeper understanding of the depths of reality more than any other thinkers and so I listened to them. But one has to be skeptical about where the line is drawn...what the limit is. Some physicists' metaphysical conclusions about "fine tuning" are not justified. They cannot (yet!) answer the deepest questions of reality...despite what they say in order to sell books or get their mugs on television or their voices on the airwaves. Stenger exorcised me of the tendency to think that "fine tuning" was a real mystery and that physicists needed to be consulted about the meaning of it all. Read "The Comprehensible Cosmos" or Noether's "Invariant Variation Problems" or read/listen to Stenger's work on how we need not conclude any metaphysical conclusion given our physical theories. It's so freeing...and so much more amazing to think how this majestic universe arises from such comprehensible simplicity. Fundamental physics is amazing...and mysterious. But in Sam Harris' words "One not need believe anything on insufficient evidence." One need not take on any metaphysical baggage suggested by any mystical physicist from Fritjof Capra through to Frank Tipler through to Paul Davies (to describe the spectrum from ridiculuous to sublime to sober "hey...have a beer and think about this...") in order to appreciate the wonder and awe-inspiring reality described by our best theories.

Stenger seems to be a rather lone, but the most eloquent voice, in skeptically challenging the vast majority of popular science books about fundamental physics and cosmology suggesting that this or that metaphysics has been cached out. It's clear most physicists are not theists and don't argue for supernatural ultimate causes...but those who write books and appear on tv and radio and podcasts seem to love *hinting* that something truly amazing is suggested by 20th and 21st century discoveries. It's appealing to be consulted like a priest on matters of ultimate meaning and our best and brightest physicists are all too often seduced by the fame that comes with suggesting a mysterious metaphysical scheme...especially when the narrator or interviewer uses the G.O.D word...or even something more mundane like the word "purpose". Stenger is like a lighthouse shining a light on precisely what the physics allows us to conclude...and what it does not. It hasn't revealed God, or purpose. It hasn't even suggested fine-tuning. Stenger isn't saying that we can positively rule-out any of those sci-fi or mystical-sounding "interpretations" of our deepest theories (like..."God did it all" or "consciousness pervades the entire universe and our brains act as aerials for quantum consciousness")...he's simply saying that we can't yet say that *any* of these theories are supported by what we know. And because of this...no such theory, however "scientifically sounding" is on any firmer ground than the idea that solipsism is true, the Flying Spaghetti Monster exists (may you be touched by his watery appendage) or that consciousness is a fundamental property of matter. All very 'interesting' - but only interesting in the way that the metaphysics of "The Lord of the Rings", "The Silmarilion" and "Middle Earth" are interesting. What we know seems to suggest that the universe is quite comprehensible so far. The laws seem to flow from "point of view invariance". Isn't that a wonderful thing that we understand that? I can't wait to find out more. Let's not simply wallow in confusion and "mystery". Let's revel in comprehension and pursue every new question until we find an answer and not stop and say "Wow...that's amazing. It implies that there's something we'll never understand". Perhaps one-day we will dig so deep that "our spade is turned" - but it hasn't happened yet. Let's not draw premature metaphysical conclusions given our limited physical observations. Read "The Comprehensible Cosmos" or even any of Stenger's writings and understand that there is an alternative to concluding that modern physics does anything more than explain the fabric of reality...and show how it's understood without requiring anything supernatural...or even "fine tuned".