Related to my previous comment on TOEs it appears interesting to remember John Von Neuman :
"As a mathematical discipline travels far from its empirical source , or still more, if it is a second or third generation only indirectly inspired by ideas coming from reality , it is beset with very grave danger . It becomes more and more purely aestheticizing, more and more "l'art pour l'art" .This need not to be bad ,if the field is sorrounded by correlated subjects , which still have closer empirical connections , or if the discipline is under the influence of men with an exceptionally well-developed taste.But there is a grave danger that the subject will develops along the line of least resistence , that the stream , so far from its source will separate into a MULTITUDE of insignificant branches and that the discipline will become a disorganized mass of details and complexities.In others words , after much abstract imbreeding a subject is in danger of degeneration"

Refreshness on theoretical physics should be always welcome , however to be technically careful with new proposals is mandatory !
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"Surfer dude stuns physicists with theory of everything

By Roger Highfield, Science Editor
Published: 6:02PM GMT 14 Nov 2007
Comments 596 | Comment on this article

The E8 pattern (click to enlarge), Garrett Lisi surfing (middle) and out of the water (right)
An impoverished surfer has drawn up a new theory of the universe, seen by some as the Holy Grail of physics, which has received rave reviews from scientists.
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Garrett Lisi, 39, has a doctorate but no university affiliation and spends most of the year surfing in Hawaii, where he has also been a hiking guide and bridge builder (when he slept in a jungle yurt).

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In winter, he heads to the mountains near Lake Tahoe, Nevada, where he snowboards. "Being poor sucks," Lisi says. "It's hard to figure out the secrets of the universe when you're trying to figure out where you and your girlfriend are going to sleep next month."
Despite this unusual career path, his proposal is remarkable because, by the arcane standards of particle physics, it does not require highly complex mathematics.
Even better, it does not require more than one dimension of time and three of space, when some rival theories need ten or even more spatial dimensions and other bizarre concepts. And it may even be possible to test his theory, which predicts a host of new particles, perhaps even using the new Large Hadron Collider atom smasher that will go into action near Geneva next year.
Although the work of 39 year old Garrett Lisi still has a way to go to convince the establishment, let alone match the achievements of Albert Einstein, the two do have one thing in common: Einstein also began his great adventure in theoretical physics while outside the mainstream scientific establishment, working as a patent officer, though failed to achieve the Holy Grail, an overarching explanation to unite all the particles and forces of the cosmos.
Now Lisi, currently in Nevada, has come up with a proposal to do this. Lee Smolin at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, describes Lisi's work as "fabulous". "It is one of the most compelling unification models I've seen in many, many years," he says.
"Although he cultivates a bit of a surfer-guy image its clear he has put enormous effort and time into working the complexities of this structure out over several years," Prof Smolin tells The Telegraph.
"Some incredibly beautiful stuff falls out of Lisi's theory," adds David Ritz Finkelstein at the Georgia Institute of Technology, Atlanta. "This must be more than coincidence and he really is touching on something profound."
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The new theory reported today in New Scientist has been laid out in an online paper entitled "An Exceptionally Simple Theory of Everything" by Lisi, who completed his doctorate in theoretical physics in 1999 at the University of California, San Diego.
He has high hopes that his new theory could provide what he says is a "radical new explanation" for the three decade old Standard Model, which weaves together three of the four fundamental forces of nature: the electromagnetic force; the strong force, which binds quarks together in atomic nuclei; and the weak force, which controls radioactive decay.
The reason for the excitement is that Lisi's model also takes account of gravity, a force that has only successfully been included by a rival and highly fashionable idea called string theory, one that proposes particles are made up of minute strings, which is highly complex and elegant but has lacked predictions by which to do experiments to see if it works.
But some are taking a cooler view. Prof Marcus du Sautoy, of Oxford University and author of Finding Moonshine, told the Telegraph: "The proposal in this paper looks a long shot and there seem to be a lot things still to fill in."
And a colleague Eric Weinstein in America added: "Lisi seems like a hell of a guy. I'd love to meet him. But my friend Lee Smolin is betting on a very very long shot."
Lisi's inspiration lies in the most elegant and intricate shape known to mathematics, called E8 - a complex, eight-dimensional mathematical pattern with 248 points first found in 1887, but only fully understood by mathematicians this year after workings, that, if written out in tiny print, would cover an area the size of Manhattan.
E8 encapsulates the symmetries of a geometric object that is 57-dimensional and is itself is 248-dimensional. Lisi says "I think our universe is this beautiful shape."
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What makes E8 so exciting is that Nature also seems to have embedded it at the heart of many bits of physics. One interpretation of why we have such a quirky list of fundamental particles is because they all result from different facets of the strange symmetries of E8.
Lisi's breakthrough came when he noticed that some of the equations describing E8's structure matched his own. "My brain exploded with the implications and the beauty of the thing," he tells New Scientist. "I thought: 'Holy crap, that's it!'"
What Lisi had realised was that he could find a way to place the various elementary particles and forces on E8's 248 points. What remained was 20 gaps which he filled with notional particles, for example those that some physicists predict to be associated with gravity.
Physicists have long puzzled over why elementary particles appear to belong to families, but this arises naturally from the geometry of E8, he says. So far, all the interactions predicted by the complex geometrical relationships inside E8 match with observations in the real world. "How cool is that?" he says.
The crucial test of Lisi's work will come only when he has made testable predictions. Lisi is now calculating the masses that the 20 new particles should have, in the hope that they may be spotted when the Large Hadron Collider starts up.
"The theory is very young, and still in development," he told the Telegraph. "Right now, I'd assign a low (but not tiny) likelyhood to this prediction.
"For comparison, I think the chances are higher that LHC will see some of these particles than it is that the LHC will see superparticles, extra dimensions, or micro black holes as predicted by string theory. I hope to get more (and different) predictions, with more confidence, out of this E8 Theory over the next year, before the LHC comes online."

Correction to the previous comment : extrinsic backgrounds fields certainly are not Schwinger sources for the string excitations in the space-time .No problem by imposing world sheet conformal sigma model invariance and thus evaluating strings scattering amplitudes in higher dimensional critical space-time

Well, space-time coordinate of one of those space-time manifold charts (covering the space-time manifold) is one object that you certainly can "travel" back and forth(remember Godel formal PDE's solution for Einstein equation ). However , what realy counts and play the role of the Newtonian time in general Einstein relativity is the unique proper-time of a given event !(this can not be back!). Note that still remains a problem to "adjust" colectivelly the proper time of several geodesics associated to the motion of several particles moving in the back ground of a given relativistic gravitational field (The twin paradox has not been fully understood !).Let me explain better : In the Einstein framework , one gives a certain energy-momentum configuration (the "Sun") (mathematically a tensor of rank two in relation to the Local dipheomorffism space-time manifold group) in the (tensorial bundle) of space-time manifold :a object from the beginning possesing solely a differentiable topological structure and after that (and if compatible with the manifold topology-Chern /Gauss theorem constraint, Riemann completeness ,etc..), one determines the topologically compatible local metric structure of the smooth space-time by means of the famous Einstein Equations.If everything is smooth from a geometrical point of view , one starts the prediction of the "falling" bodies trajectories in this gravitational field throught the solution of the Boundary-Value Sturm liouville like problem associated to the geodesics non linear equations (you should know the beginning and the final point of the falling body trajectory into the space-time ,not the initial point and its "initial velocity" as in Newton Equation).Now one can make further steps on the Einstein program by exchanging the mater-energy Einstein's source by boundary ad-hoc conditions simulating point sources -delta sources-(not dipheomorffism covariant) ,like the Schwartz-Schild solution for Einsteinian particle motions around the Sun), and thus leading to a rich mathematical universe ( astronomical and astrophysical/cosmological observable ?)

Let us put in a correct perspective quantum string theory for TOE. Firstly it is important to remark that a full understanding of what is really Quantum Mechanics is far to be completely understood in its foundational aspects ,althougth its huge operational-quantitative success.For instance, even in the usual non relativistic quantum mechanics , certainly the notion of electronic orbitals in N-electron atomic physics appears to be a mathematical suitable approximation for the full N-electron atomic wave function.On the other hand in Quantum Field Theory , this ad-hoc choice of what is free and what is interaction is not so "ad-hoc", at least in the QFT (perturbative) scattering sector: free in and out fields are primary objects producing physically observables free N-particles (lorentz invariant!) wave functions-so perturbation is building around them and carrying with the formalism all notions of renormalizations , dispersions relations etc.. .Now quantum strings : Strings are supossedly observable for us mainly through scattering among its excitations by means of an already fixed sigma-model two-dimensional quantum dynamics taking place in the somewhat ficticious purely two dimensional string parameter space-time, where are operating two scales of interaction : one is entirely ruled by the intrinsic string topological genera and other governed by the extrinsic space-time coupling constant , namely : The Regge Slope parameter. So string theory for TOE is a proposal for pure S-Matrix "Heisenbergnian" on-shell "theory" for all particles scattering in Nature (including gravitons). Now the theory's "granus salis" (points not completely grasped-at least for this reader !): Back ground fields are fixed extrinsic classical field configurations fully determined by the imposition of conformal invariance for any genera (which certainly does not affects the intrinsic 2d UV-theories'behavior,but affects its IR intrinsic behavior as a 2d QFT) and at any order in the Regge Slope coupling (all these conformal invariance phenomena quite specific to Polyakov's action proposal , possibly not for a Nambu-Goto string action reformulation of TOE).And at the same time , they are expected to be Schwinger sources (even quite non linear) for the string excitations and to be functionally differentiated in the string path-integral later .Another point is related to Kaluza-Klein Theories -It appears that quantum geometrical theories appear to be trivial QFT theories when used to describe scattering in space-time extrinsic manifolds of higher dimensionality (lambda four scalar QFT is expected to be trivial for D strictly greater than four!). As a conclusion : at most Strings are useful theoretical labs for a fully understanding of what really is Quantum Mechanics (SchrodingerX HeisenbergXEinsteinXNelson) , if there are no experimental tests for its predictions .By the way,space-time supersymmetry still remains solely as a theoretical lab in Particle Physics, nothing more!.

Well , it appears to me that string theory is a interesting attempt to "quantize" the space-time manifold (added with suitable supersymmetric structures ).Everything in higher dimensions become reduced to two-dimensional quantum field path integral models "living"on the string chart manifold (the intrinsic two-dimensional "string space-time").However , people impose dipheomorffism invariance on this intrinsic string parameter "space-time" which unfortunatelly get mixed with 2D conformal invariance , when one uses the sigma model Polyakov' action to assign "energy" for these "quantum -fluctuating extrinsic /observable higher dimension space-time process (quite different from the more geometrical Nambu-Goto string action ).In order to solve this problem one thus impose full sigma model conformal invariance by restricting that all strings Schwinger sources (the string higher dimensional field back grounds-including the own extrinsic space time manifold dimension!)to lead to a vanishing beta function for the sigma model Polyakov action at any perturbative order of the new universal coupling constant-the String length scale/Regge parameter.This produces an apparently well defined (?,and about the infrared 2D cut-off remotion on the perturbative Feynman calculationson the intrinsic string space-time ?) 2D Field theory for the extrinsic space-time quantum energy action, besides of fixing the string Schwinger sources to satisfy the usual Einstein-Maxwell-etc field equations at one loop and the extrinsic space-time dimension and the classical manifold topology of the extrinsic space-time to be fixed, when one has supersymmetry (Spin manifold space time structures,etc..).At this point , one has an apparently well defined quantum -mechanical framework to evaluate numerically scattering amplitudes (including quantum gravity!-the old dream ) to compare with the experimental results.That is the problem on this new quantum-mechanical framework : as far as I know nothing has been matched with the usual qed,qcd,etc results!(anomalous particle magnetic momentum, deduction of the asymptotic freedom in QCD ,The Higgs mechanism on the weak sector ,etc.