The week’s eSkeptic offers two reviews of The Road to Reality: A Complete Guide to the Laws of the Universe, by Roger Penrose (Knopf Random House, 2005, ISBN 0679454438).
The first review, How Vast is Our Ignorance, is by James N. Gardner, author of BIOCOSM. BIOCOSM (www.biocosm.org) was selected as one of the ten best science books of 2003 by the editors of Amazon.com.
The second review, The Key to the Universe, is by Michael Shermer, originally published in the New York Sun, March 2005.
How Vast is Our Ignorance?
a review by James N. Gardner
The most difficult thing for lay people to understand about science, Nobel laureate Murray Gell-Mann once told me after a lecture in Portland, Oregon, is how very little scientists truly comprehend about the basic nature of nature, how vast is our ignorance of the fundamental reality of the cosmos. Gell-Mann’s statement reminded me of the comment of that supreme master of quantum physics, Nobelist Richard Feynman, who once famously remarked: “I think it can be safely said that nobody understands quantum mechanics.”
Isaac Newton, the father of modern physics and author of the Principia — arguably the single most sublime achievement of the human intellect—made exactly the same point some 300 years earlier when he said:
I don’t know what I may appear to the world, but to myself I seem only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
Why is it that our greatest geniuses — Gell-Mann, Feynman, Newton—can humbly concede how pitifully limited is the reach of deep human insight and comprehension while lesser spirits noisily proclaim the certainty of their conclusions and forcefully dismiss dissent, doubt, or skepticism?
The short answer, I think, is that humans crave certainty, even false certainty, in preference to the sense of vertigo induced by a clear-eyed acknowledgment that we are, at least most of the time, stumbling in the dark down an unmarked path through the baffling wilderness of an unknown — perhaps unknowable — reality. Facing up to the limits of our knowledge and the enormity of our ignorance is an acquired skill, to put it mildly. But it is a skill well worth cultivating. For if we don’t realize where the shoreline of reasonably well established scientific theory ends and the vast sea of undiscovered truth begins, how can we possibly hope to measure our progress toward a deeper and more encompassing scientific enlightenment?
That is the leitmotif of Oxford physicist Roger Penrose’s The Road to Reality: A Complete Guide to the Laws of the Universe. The great virtue of this massive tome — an imposing brick of a book that bristles with equations and clocks in at a daunting 1,099 pages — is not so much the encyclopedic review it provides of the history and current status of theoretical physics but rather its forthright acknowledgment that, for all its magnificent achievements, modern science remains a flickering candle surrounded by inky mystery. With refreshing candor, Penrose forcefully underscores the extent of our ignorance about the origin — and indeed the very nature — of the physical laws that govern the operation of our magnificent universe. What the enterprise of science has compiled to date, in Penrose’s view, is a decidedly incomplete guide to the laws of nature:
I hope that it is clear, from the discussion given in the preceding sections that our road to understanding the nature of the real world is still a long way from its goal. Perhaps this goal will never be reached, or perhaps there will eventually emerge some ultimate theory, in terms of which what we call “reality” can in principle be understood. If so, the nature of that theory must differ enormously from what we have seen in physical theories so far.
The great iconoclasts and contrarians of science — British cosmologist Fred Hoyle, Princeton physicists John Wheeler and Freeman Dyson, Thomas Gold, Francis Crick, Albert Einstein, and Roger Penrose — play a critically important role in maintaining the intellectual integrity of the scientific enterprise. As Gold put it perfectly a few years ago:
New ideas in science are not right just because they are new. Nor are old ideas wrong just because they are old. A critical attitude is clearly required of every seeker of truth. But one must be equally critical of both the old ideas as of the new. Whenever the established ideas are accepted uncritically and conflicting new evidence is brushed aside or not even reported because it does not fit, that particular science is in deep trouble.
Penrose, a quintessential scientific contrarian, is consumed by the fear that uncritical adherence to ideas deemed mainstream by the scientific establishment might blind us to theoretical possibilities that, while radically novel, may offer a deeper understanding of our queer cosmos. He strives heroically in The Road to Reality to forestall that intellectual calamity, reminding us in the process of just how enormous is the distance that we have yet to travel down the road that may someday lead to a full understanding of reality:
There are deeply mysterious issues about which we have very little comprehension. It is quite likely that the 21st century will reveal even more wonderful insights than those we have been blessed with in the 20th. But for this to happen, we shall need powerful new ideas, which will take us in directions significantly different from those currently being pursued. Perhaps what we mainly need is some subtle change in perspective — something that we all have missed…
The Key to the Universe
a review by Michael Shermer
A couple of years into the editing and publishing of Skeptic magazine, I began to regularly receive manuscripts that I filed as “theories of everything.” I later discovered that all science-magazine editors receive such manuscripts, as do prominent scientists at leading institutions. These papers are mostly attempts at constructing all-encompassing explanatory theories, almost exclusively in the physical sciences, typically claiming that Isaac Newton, Albert Einstein, and Stephen Hawking are wrong, and that the author’s 10-page, single-spaced typed essay, sans references, contains the secrets of the cosmos.
A manuscript titled “Infinite Dynamics,” for example, presented “the opposing force of structure as the singular force of reality” that “establishes the preeminence of philosophy;” goes “beyond Einstein;” and represents “an historic, classical, artistic, scientific, philosophical paradigm shift”! A theory called “Photonics” promised “Einstein’s unified-field theory now complete, all forces finally unified,” and (as a bonus) “fundamental cause of gravity found.”
Another fellow claimed:
I have discovered the previously unknown invisible particle that fully explains light and all forms of energy. I call it the froton particle. Einstein didn’t know about the froton particle — but you will. I can’t email a drum roll, and don’t want to pontificate. Inappropriately or not, if only out of respect for Einstein and physicists as far back as Aristotle — I’ve chosen the words to introduce the unified field theory. “Behold the froton particle … the key to the universe.”
To most of these would-be revolutionaries, I respond with a short note explaining that in science if you want to challenge an existing paradigm, it is best to begin with a thorough study of what has already been done, then proceed to dismantle it in those places of greatest weakness or lack of evidential support (and to do so in peer-reviewed journals). This is typically met with a “harrumph!” and an accompanying explanation that the new theory in question is so revolutionary scientists will never accept it.
As a testimony to the falseness of this latter statement, and as a recommendation for close study, I shall forthwith recommend to such wanna-be radicals Roger Penrose’s The Road to Reality. Mr. Penrose’s book is the very antithesis of such flapdoodle. It really is, as its subtitle proclaims, “a complete guide to the laws of the universe,” at least as we now understand them.
Mr. Penrose — a professor of mathematics at Oxford University, a Fellow of the Royal Society, and the winner of numerous prestigious awards in physics and mathematics — is one of the most qualified scientists to pen such a tome. At just under 1,100 pages, this is his magnum opus, the culmination of an already stellar career and a comprehensive summary of the current state of physics and cosmology. It should be read by anyone entering the field and referenced by everyone working in these and related sciences.
But first a warning. In his book A Brief History of Time, Stephen Hawking remarked that his publisher told him that, for every equation he included, book sales would drop by half. Mr. Penrose’s book, though it has the imprint of a popular publishing house, is full of mathematical equations and technical diagrams. Yet professional scientists cannot accuse Mr. Penrose of dumbing-down the science, and the author’s prose is so lucid the reader can grasp his point even when the mathematics fly overhead.
Science may be conservative — with so many goofball theories floating around, it has to be — but The Road to Reality shows just how radical scientists can be in accepting, or at least seriously testing, hundreds of remarkably revolutionary ideas that have been proposed since the time of Plato and Aristotle about how the world works.
Beginning with such deep mysteries as whether mathematical truths are discovered or invented, Mr. Penrose reviews the relationship between mathematics and the physical world; the geometry of logarithms, powers, and roots; real-number and complex-number calculus; topology, surfaces, and symmetry; finiteness and infinity; the geometry of space and time; Maxwell’s and Einstein’s fields; the Big Bang and speculative theories of the origins of the universe; the relationship between gravity and quantum theory; “spooky action-at-a-distance” experiments (about which more in just a moment); and some final speculations about the state of physics today and what might be in store for us in the 21st century. In short, this is the most comprehensive work of physics since Richard P. Feynman’s 1963 classic three-volume set, The Feynman Lectures on Physics.
Mr. Penrose never shies from philosophizing about the implications of a theory. For example, after describing quantum mechanics as “one of the supreme achievements of the 20th century” that “explains a great many phenomena that had been profoundly puzzling in the 19th [such as the stability of atoms, the nature of chemical bonds, and solid/liquid/gas phase transitions, just for starters]” and stating that it has “provided us with a revolution in our picture of the real physical world that is far greater even than that of the curved spacetime of Einstein’s general relativity,” Mr. Penrose then asks provocatively: “Or has it? It is a common view among many of today’s physicists that quantum mechanics provides us with no picture of ‘reality’ at all!”
What Mr. Penrose is getting at here is a very deep question in the philosophy of science about the nature of reality. As Stephen Hawking once famously said: “I don’t demand that a theory correspond to reality because I don’t know what it is. Reality is not a quality you can test with litmus paper. All I’m concerned with is that the theory should predict the results of measurements.” This is the positivist position, and it is one way of dealing with the spookiness of some quantum-mechanical findings.
Consider the phenomenon called by Einstein “spooky action at a distance.” Under certain experimental conditions the actions of a sub-atomic particle here can instantly effect the actions of another subatomic particle there, even if here and there are separated by immense distances — miles, light years, whatever. This seems to imply that information is being transported faster than the speed of light — the universal speed limit, according to Einstein. Physicists and philosophers have strained their brains trying to make sense of how this could be possible (and in New Age circles, such quantum-mechanical findings are proclaimed as explanations for telepathy, telekinesis, and other paranormal pabulum). One way to avoid an aneurism is to accept the experimental findings and not worry what it implies about the nature of reality.
But Mr. Penrose’s book is about the road to Reality, and so we can expect him to be concerned about such ontological facts. He deals with the problem in an entire chapter, in which he carefully and objectively reviews six quantum theories (Copenhagen, many worlds, environmental decoherence, consistent histories, pilot-wave, and new theory of objective R). Then, “with apologies to many of my friends,” he devotes another chapter to explaining “that there are powerful positive reasons, over and above the negative ones put forward in the preceding chapter, to believe that the laws of present-day quantum mechanics are in need of a fundamental (though presumably subtle) change.”
And here I offer a second warning. Mr. Penrose is one of the half-dozen top theoretical physicists in the world, and as such this is not a physics textbook sans authorial commentary or bias. Mr. Penrose puts his unique stamp on the great debates in his own field (and rightly so), and he criticizes those he feels deserve it. To his credit, he always makes it clear where he is departing from his colleagues, how, and why.
In the case of quantum mechanics, for instance, Mr. Penrose feels that even though changes in the theory will “come from within accepted physical principles and from observed facts about the universe,” he finds it “remarkable how few of today’s quantum physicists are prepared to entertain seriously the idea of an actual change in the ground rules of their subject.”
Likewise he explains that, at present, we have two fundamental theories of physics, general relativity and quantum field theory, which are apparently incompatible. Unifying them would result in a real Theory of Everything. “The usual perspective, with regard to the proposed marriage between these theories, is that one of them, namely general relativity, must submit itself to the will of the other,” Mr. Penrose explains. In other words, general relativity “must bend itself appropriately to fit into the standard quantum mould.” Mr. Penrose then devotes a chapter to explaining why he thinks it will be the other way around.
And so it goes throughout this sweeping visage of epistemology and physics, to the end of this ultramarathon, when Mr. Penrose concludes: “It is quite likely that the 21st century will reveal even more wonderful insights than those that we have been blessed with in the 20th. But for this to happen, we shall need powerful new ideas, which will take us in directions significantly different from those currently being pursued. Perhaps what we mainly need is some subtle change in perspective — something that we all have missed.”
There is hope for all those would-be Newtons, Einsteins, and Hawkings out there. But first they must master the 2,500 years of science that came before, so well illuminated here by Roger Penrose.