Is String Theory Even Wrong? Peter Woit
For nearly 18 years now, most advanced mathematical work in theoretical particle physics has centered on something known as string theory...Fifteen years ago Edward Witten of the Institute for Advanced Study made the widely quoted claim that "string theory is a part of 21st-century physics that fell by chance into the 20th century," so perhaps it is now time to begin judging the success or failure of this new way of thinking about particle physics....
String theory predicts that the world has 10 space-time dimensions, in serious disagreement with all the evidence of one's senses. Matching string theory with reality requires that one postulate six unobserved spatial dimensions of very small size wrapped up in one way or another. All the predictions of the theory depend on how you do this, but there are an infinite number of possible choices, and no one has any idea how to determine which is correct....
The second concern is that even the part of string theory that is understood is internally inconsistent. This aspect of the theory relies on a series expansion, an infinite number of terms that one is supposed to sum together to get a result. Whereas each of the terms in the series is probably finite, their sum is almost certainly infinite...
These two problems have been around since the earliest work on string theory, along with the hope that they would somehow cancel each other out.
The experimental situation is similarly bleak. It is best described by Wolfgang Pauli's famous phrase, "It's not even wrong." String theory not only makes no predictions about physical phenomena at experimentally accessible energies, it makes no precise predictions whatsoever....
With such a dramatic lack of experimental support, string theorists often attempt to make an aesthetic argument, professing that the theory is strikingly "elegant" or "beautiful." Because there is no well-defined theory to judge, it's hard to know what to make of these assertions....
...the past 15 years of research in particle theory make depressingly clear one form such an end could take: a perpetual, well-promoted but never-successful investigation of a theory that has no connection with the physical world. If only physicists have the will to abandon a failed project and start looking for some new ideas, this sad fate can be avoided.
Peter Woit (born September 11, 1957) is an American theoretical physicist. He is a Senior Lecturer in the Mathematics department at Columbia University. Woit graduated in 1979 from Harvard University with bachelor's and master's degrees in physics. He obtained his PhD in particle theory from Princeton University in 1985, followed by postdoctoral work in theoretical physics at State University of New York at Stony Brook and mathematics at the Mathematical Sciences Research Institute (MSRI) in Berkeley. He spent four years as an assistant professor at Columbia. He now holds a permanent position in the mathematics department, as Senior Lecturer and as Departmental Computer Administrator.
String cosmology is a part of theoretical physics that has become detached from experiments. String cosmologists are free to imagine universes and multiverses, guided by intuition and aesthetic judgment alone. Their creations must be logically consistent and mathematically elegant, but they are otherwise unconstrained. That is why Wertheim found the official string cosmology conference disconcertingly similar to the unofficial Natural Philosophy conference. The insiders and the outsiders seem to be following the same rules. Both groups are telling stories of imagined worlds, and neither has an assured way of deciding who is right. If the title Physics on the Fringe fits the natural philosophers, the same title also fits the string cosmologists.
The fringe of physics is not a sharp boundary with truth on one side and fantasy on the other. All of science is uncertain and subject to revision. The glory of science is to imagine more than we can prove. The fringe is the unexplored territory where truth and fantasy are not yet disentangled. Hermann Weyl, who was one of the main architects of the relativity and quantum revolutions, said to me once, “I always try to combine the true with the beautiful, but when I have to choose one or the other, I usually choose the beautiful.” Following Weyl’s good example, our string cosmologists are making the same choice.
And how are things going with string theory? The promises and hopes from the 1980s have not worked out. They thought they’d find the right Calabi-Yau manifold and the fermion multiplets and masses would pop out and they’d have the whole thing wrapped up before lunch. But that didn’t happen. String models grew increasingly complicated. And with every fanciful step they made away from the Standard Model, the more likely they were to be wrong; they were mesmerized by their own mathematical constructions, which kept them busy but were much more complex than the Standard Model they were trying to explain. String theory became a postmodernist monstrosity, lumbering forward on self-provided momentum without ever receiving the pruning from experimental verification that physics demands. The closest thing to a physical prediction that string theory has ever produced is that there should be superparticles, but these have not shown up. String theory models lost connection to the physical world. Other physicists and mathematicians were left wondering if string theorists had joined some sort of cult.
String theory models lost connection to the physical world. Other physicists and mathematicians were left wondering if string theorists had joined some sort of cult.
….it accommodates a consistent combination of quantum field theory and general relativity
Sheldon Lee Glashow (born December 5, 1932) is a Nobel Prize winning American theoretical physicist. He is the Metcalf Professor of Mathematics and Physics at Boston University and Higgins Professor of Physics, Emeritus, at Harvard University.
There is today a disconnect in the world of physics. Let me put it bluntly. There are physicists, and there are string theorists. Of course the string theorists are physicists, but the string theorists in general will not attend lectures on experimental physics. They will not be terribly concerned about the results of experiments. They will talk to one another.
“I simply can’t imagine why any sane person would imagine, discuss, or mention, except insultingly, the concept of a theory of everything. It's a stupidity.”
...there ain't no experiment that could be done nor is there any observation that could be made that would say, "You guys are wrong." The theory is safe, permanently safe. I ask you, is that a theory of physics or a philosophy?
Ros, entirely OT but I had got you mixed up with Ora. Thus the following link was intended for you not Ora, with my apologies
I see claims ranging from
1. "string theory, already on life support, is starting to circle the drain..." to
2. "string theory is still the only game in town."
String Theory provides great speculation, but so far no actual value, no insight, no knowledge.
All I heard there was a long and oversimplified explanation of string theory. I didn't hear any insight.
Looking back, I’m gratified at how far we’ve come but disappointed that a connection to experiment continues to elude us. While my own research has migrated from highly mathematical forays into extra-dimensional arcana to more applied studies of string theory’s cosmological insights, I now hold only modest hope that the theory will confront data during my lifetime....
Should decades drift by without experimental support, I imagine that string theory will be absorbed by other areas of science and mathematics, and slowly shed a unique identity.
...researchers had discovered ever larger collections of shapes that passed mathematical muster, driving the number of candidates into the thousands, millions, billions and then...into numbers so large that they’ve never been named. Against this embarrassment of riches, string theory offered no directive regarding which shape to pick....The dream of extracting unique predictions from string theory rapidly faded.
Susskind was arguing that if the mathematics does not identify one particular shape as the right one for the extra dimensions, perhaps there isn’t a single right shape...Our universe would then be just one of a vast collection, each with detailed features determined by the shape of their extra dimensions...
With or without string theory, the multiverse is a highly controversial schema, and deservedly so. It not only recasts the landscape of reality, but shifts the scientific goal posts....Most physicists, string theorists among them, agree that the multiverse is an option of last resort...