Roger Penrose: Fashion Faith and Fantasy in the New Physics of the Universe

Ten years in the making, Roger Penrose delivers a masterpiece.

Mathematicians claim him as their own.

Physicists claim him as their own.

Cosmologists claim him as their own.

Lee Smolin, founder of Perimeter Institute and himself one of the most innovative theoretical physicists in the world, says, “Roger Penrose is the most important physicist to work in relativity theory except for Einstein. He is one of the very few people I’ve met in my life who, without reservation, I call a genius.”

Cal Tech’s Sean Carroll, who currently is riding the bestselling wave of his own sensational synthesis, The Big Picture, says, “Penrose is one of those scientists who rattles off brilliant ideas like most of us brush bread crumbs from our shoes”.

Penn State’s Abhay Ashtekar, one of the world’s leading relativists who once studied with Penrose, says, “He has his way of dreaming, groping in “the dark and coming up with completely unbelievable ideas.”

And then there is the great Martin Rees, astronomer royale of England; Kip Thorne (on the short list for a Nobel Prize for his role in the Feb 11, 2016 detection by LIGO, after a century of waiting and searching, of Einstein’s postulated gravity waves); and George Ellis, one of the preeminent cosmologists of our time. Each of them, pause in their own way, to pay tribute to “the genius of Roger Penrose”, to the way in which he “revolutionized cosmology” by introducing topological methods for the first time; and to his famous “singularity theorems” showing that singularities are actual phenomena which occur in gravitational collapse irrespective of symmetry.

FULL DISCLOSURE

Twenty five years ago, shortly after I had written, “A Psychoanalyst Takes The Turing Test”, my first and probably best known paper, a friend introduced me to Roger Penrose. I was encouraged to read his then new and already highly controversial book The Emperor’s New Mind. Penrose, I was told, was studying from a rigorous scientific and philosophical standpoint what I was exploring from an interpersonal psychodynamic perspective. Our common subject was consciousness. One shared belief was that something was wrong and needed to be changed. Penrose’s solution was to reformulate quantum mechanics so as to incorporate consciousness in some way into the pantheon of usable physical constructs. My vastly less radical idea was simply — to bypass the fashionable computer model of information processing and binary thinking and focus instead on the human centered, emotionally charged dynamic unconscious. My strategy was to take full advantage of the fact computer scientists at that time (and to this day still) did not seem to understand that thinking to a considerable extent is unconscious, dynamic and filled with emotions.

My appetite thus whetted I decided to give Penrose a try. My greatest fear — that he would be too technical for my taste — was quickly alleviated. Penrose I soon discovered was not what is called a ruthless reductionist. He was not a monist. He did not believe, that if you only knew how, you could shrink everything down to just one physical thing. He was not a dualist. He did not believe that everything could be fitted into one of just two categories; it was mental or physical. More importantly, Penrose was not a binary thinker. He did not believe that thought was primarily a series of yes or no questions and answers. He was a pluralist in that he believed in at least three domains of reality; the physical, the mental, and the mathematical. He was a realist in the sense that he believed that there was something out there existing independently of our minds, something we do not invent, do not construct but discover. He was a platonist inasmuch as he believed — as do a number of other great mathematicians — that mathematics in some strange, non-physical, but quite real sense, also exists out there in an á priori way.

More meaningful to me, was that Penrose in his own way was a humanist, trying to make contact with the most diversified audience possible. He wrote for the very few who could scale the same intellectual summits he could, he wrote for the experts, for the postdocs, for the doctrinal candidates, for the graduate students; but he also wrote for the non-professionals, for the 99.99 percent of the population who, although not choosing to devote their lives to science, were nevertheless curious, sometimes passionately so, to understand better how the universe was born.

To me it was endearing that Penrose would sometimes preface his books with an advisory warning to readers as to the degree of difficulty to be encountered in the chapters ahead, Thus, we were told, this chapter could be avoided, that chapter could be skimmed, but these sections needed to be read. Should the math at times threaten to become a bit overwhelming, not to worry. There was an appendix at the back to help clarify troublesome concepts (the only problem being that sometimes the appendix itself would be in need of its own appendix).

Although he stands pretty much alone in contemporary physics, Penrose does not consider himself a “maverick”. He notes there is much that he admires. He is, in fact, the opposite of a maverick, he is a conservative. He means when science gets something right, it really gets it right. His definition of a great scientific theory — Newtonian mechanics which in 1969 was still good enough to get us to the moon; Einstein’s General Theory of Relativity which on Feb. 11, 2016, one hundred years after its inception, achieved its greatest experimental confirmation (first detection of gravity waves and black holes) and James Clerk Maxwell, whose nineteenth century theory of electromagnetism is still standing — is one which endures.

Penrose, in short, far from being a radical, considers himself to be someone deeply committed to the most time-tested foundational principles in physics. If he is a revolutionary, he is a non-violent revolutionary. He is unafraid to follow the great equations of physics, wherever they take him. For fifty years, he has travelled the intellectual road less travelled and (judging from his new book) he is not about to stop.

Now onto the book:

FASHION

Penrose’s chief example of fashion is string theory. He notes he by no means is an expert in a field that is highly technical and that therefore his remarks will be necessarily general. Furthermore, since these initial lectures were given in 2003, by invitation of Princeton University Press, there have been three “highly critical accounts of string theory”: Not Even Wrong by Peter Woit, The Trouble with Physics by Lee Smolin and Farewell to Reality by Jim Baggott.

According to Penrose, when it comes to string theory “there appears to be no results whatever that provide it with experimental support”.

Moreover if we try to use the criterion of mathematical beauty we are easily led astray. “General Relativity,” says Penrose, “is certainly a very beautiful theory, but how does one judge the elegance of physical theories generally?”

Penrose admits when he first heard about string theory’s original ideas he found them to be “strikingly attractive and of a distinctive compelling nature.”

As for the famous standard model of particle physics, Penrose observes that there are “powerful scientific reasons for striving to go beyond the standard model for which its theory provides no explanation whatsoever.”

String theory suggests, says Penrose, a way out of this conundrum. It proposes that the basic ingredient of matter is not a point particle, but 1 — dimensional, like a curved line. It was particularly appealing to Penrose that these “string world sheets” could, in an appropriate sense, be regarded as Riemann surfaces. It was Bernard Riemann’s brilliant but neglected theory of curved surfaces, we remember, that proved to be the missing linchpin in Einstein’s great idea of curved space time.

Not surprisingly Penrose, a committed relativist, has deep questions concerning “the physical relevance of quantum theories such as supra-dimensional string theories for which the number of spatial dimensions is greater than the three we directly perceive. “What happens”, Penrose asks, “to the floods of excessive degrees of freedom that now become available to the system, by virtue of the huge functional freedom that is potentially available in the extra spatial dimensions? Is it plausible that these vast numbers of degrees of freedom can be kept hidden away and prevented from completely dominating the physics of the world in such schemes?”

Roger Penrose, one of the greatest geometers of the past one hundred years, can not accept string theory’s need for six additional, curled up, invisible, dimensions:

“The acceptance by a highly knowledgeable section of the physics community, of such a hybrid of great geometrical sophistication on the one hand and a seeming disregard for an overall geometrical coherence on the other is something that I find extremely puzzling”.

Roger Penrose is saying, in effect, that he knows in his bones — despite thirty years of protestations by some of the most brilliant string theorists in the world — that there can not possibly be more than the three dimensions plus time that we have seen, and only seen, from time immemorial. Penrose has made it abundantly clear that there is no twentieth century physicist he respects more than Einstein. There is no theory of gravity he trusts more than Einstein’s special and general theory of gravity. There is no theory of space-time he holds in higher esteem than Einstein’s great theory of curved space-time.

So it is perhaps not so surprising that Penrose may be the only physicist in the world who approaches the great divide between quantum mechanics and the theory of general relativity — the two pillars of contemporary physics that do not meet, that look right past one another — almost wholly from the perspective of the relativist that he is and has always been. He recognizes, as does the great majority of theoretical physicists, that there is a need for a quantum theory of gravity. But he does not believe that the main overhaul will be solely on the macroscopic side of general relativity. He is willing to split the difference; willing to meet the quantum physicists “about 50% of the way.”

Where does Penrose’s unflinching confidence come from? One very likely source is his superb physical insight into the large geometric structure of space-time. (more disclosure: on May 8th in Manhattan, — during a wonderful wide-ranging conversation with Sean Carroll two days before the scheduled release of his subsequent best-selling, new book, The Big Picture — he suddenly leaned across the table — and said (vis- a- vis our protagonist), “I think Roger Penrose understands the fourth dimension better than anyone who ever lived!” And so taken aback by the statement was I that I neglected to ask him the question I should have: “And what is it Roger Penrose understands about the fourth dimension that no one else in the world understands?”).

That said, Penrose makes it clear that there is much of contemporary quantum mechanics that he solidly accepts. He readily acknowledges the mathematical magnificence of quantum mechanics; its status as the most revolutionary theory by far that science has ever seen; its unparalleled unbroken record of having passed with flying colors every experimental test ever thrown at it.

But he can not accept when quantum mechanics brazenly, with absolutely no proof to support it, dispenses with indispensable elements of Einstein’s general theory of relativity. He can not accept, as quantum physicists often do, that the entire universe is quantum mechanical. Nor can he accept that quantum assertions concerning particle-wave duality, superpositions, the collapse of the wave front into the mind of the observer, and, famously the Schrodinger cat superposed as both dead and alive, the claim that there is no reality other than a series of probability statements, and, of course, the insistence that we live in a world of hidden supra-dimensionality — can possibly be the last word in theoretical physics.

Lest this seem uncharitably contrarian, consider this very recent post by the up-to-date young ubiquitous (and brilliant) quantum phenomenologist, Sabine Hossenfelder, on her popular science blog, backreaction (August 6th, 2016):

“During my professional career, all I have seen is failure, a failure of particle physicists to uncover a more powerful mathematical framework to improve upon the theories we already have. What worries me is our failure to learn from failures. Rather than trying something new, we have been trying the same thing over and over, expecting different results.”

What then does Roger Penrose believe? He believes that a unification of some kind of quantum mechanics and general relativity is in the offing. He believes that there will be an emerging theory of quantum gravity, that rather than replace or modify general relativity will itself incorporate time-tested relativistic, gravitational principles. He believes that when modern technology begins to catch up to the hitherto inaccessible world of micro-physics the way it has with general relativity (LIGO’s revolutionary first detection of gravity waves on 2/11/16) — we will begin to see for the very first time experimental cracks in the façade of quantum mechanics, cracks that have been only glimpsed but never proven.

And Penrose believes that it may very well be relativity theory and not quantum mechanics that will help solve the mystery of the Big Bang.

At eighty four, it is not likely we will see another book like this. Penrose has now produced three visionary books, each highly controversial that will be long remembered: The Emperor’s New Mind; The Road to Reality: A Complete Guide to the Laws of the Universe (a 1000 page magnum opus that to my knowledge no one has ever read to completion); and Fashion, Faith and Fantasy in the New Physics of the Universe.

He is 84, but he is not looking back.

He can still write passages that burn with a hard gemlike flame.

There is no dimming, no “dying of the light”.

His genius — as anyone who picks up a copy of the book can discover in just a few pages — continues to shine.

Gerald Alper

author, God and Therapy

what we believe when no one is watching