However, if A-D-E is not Popper falsifiable then it's not physics - just a framework.

Same problem as string theory according to some.

So, Saul-Paul is there a way to falsify A-D-E?

What I don't get is how after 40 years and so many highly paid string theorists in top universities world-wide they can still claim that they don't know what string theory is? e.g. David Gross's video http://www.youtube.com/watch?v=Mo05DBiCrLc

No organizing principle like the equivalence principle in GR and the local gauge principle in QFT. What am I missing here?

Some say string theory fell from the 21st Century- but it's already the 21st Century. :-)

What is good physics?

Good physics makes a difference that makes a difference experimentally.

On Nov 20, 2010, at 8:28 PM, Saul-Paul and Mary-Minn Sirag wrote:

Jack,

String theory is falsifiable. See the final paragraph of Gordon Kane's paper, "String Theory and the Real World" Phys. Today, Nov.2010 You sent it to us. Did you read it?

Not yet.

Here's that last paragraph:

Some of those who talk about testing string theory, and most critics of theory, are assuming the 10D or 11D approach and want somehow to test the theory without applying it to a world where tests exist. That is analogous to asking a Lagrangian to be falsifiable without applying it to any physical system. Is 10D string theory falsifiable? That is not the relevant question. What matters is that the predictions of the 10D theory for the 4D world are demonstrably testable and falsifiable. If no compactified string theory emerges that describes the real world, physicists will lose interest in string theory. But perhaps one or more will describe and explain what is observed and relate various phenomena that previously seemed independent. Such a powerful success of science would bring us close to an ultimate theory.

It seems Kane is saying there is no test of the current version of string theory? What am I missing?

[end of quote from Kane]

What I call ADEX theory is not falsifiable, because I defined it as the study and application of all the A-D-E Coxeter graphs. The appropriate issue here is not falsifiability but usefulness.

Fine, but how is it useful for physics is the question? I agree it's good math and perhaps will be useful in the future.

I'm attaching my my "ADEX dimensions" (2008) paper:

See especially page 2, where I list the many mathematical objects classified (and thus unified) by the A-D-E graphs. These graphs provide a way to transform between these objects. What is difficult (or impossible) to see (and calculate) via one object may be easy for an alternative object. Each object is a different window into a vast underlying structure, which I take to be Reality in all its complexity.

There is hardly any area of physics which does not use one or more of these mathematical objects calculate consequences of various models and theories.

This is both pure and applied mathematics, in the same sense that Newton's calculus was both pure and applied mathematics. Newton's derivatives were derivatives with respect to time; and time is physical. Newton's theory of gravity was indeed (in the 20th century) falsified, yet it continues to be useful -- extremely so.

All for now;-)

Saul-Paul

Fine, but it seems that quantum chromodynamics for example is much more useful at present e.g. supercomputer computation of the hadronic masses.

On Nov 20, 2010, at 5:54 PM, Tony Smith wrote:

Saul-Paul,

you are correct that LHC results could sort wheat from chaff in unified theories.

1 - If LHC finds no standard supersymmetry partners, then the Kane Superstring approach is dead.

Yes. Popper falsifiable - good physics.

2 - If LHC finds no indication (direct or indirect) of Garrett Lisi mirror fermions, then the Lisi E8 approach is dead.

Yes. Popper falsifiable - good physics.

3 - If the LHC finds either standard supersymmetry partners or mirror fermions, then my approach to E8 (no mirrors and no conventional supersymmetry) is dead.

Yes. Popper falsifiable - good physics.

Also if the LHC finds WIMPS or other real dark matter particles then my theory of dark matter as positive pressure quantum vacuum is dead.

However, as you say Saul-Paul, all those approaches are connected to A-D-E stuff, so no matter what, it is likely that A-D-E will remain alive.

Tony

Begin forwarded message:

From: Tony Smith Date: November 19, 2010 7:46:46 PM PST

To: JACK SARFATTI Subject: GUT and E8

Jack, with respect to the Lubos Motl blog entry that you quoted and propagated:

Lubos said: "... The speedy proton decay was obviously a wrong prediction...[ of ]... grand unification ... based on the gauge group SU(5) ..."

That may or may not be true. The conventional interpretation of experimental results is that what Lubos said about SU(5) GUT is true, but there are reasonable alternative interpretations that indicate that SU(5) GUT may not be ruled out by experimental results. See, for example, a recent (within past 5 years) paper at http://arxiv.org/abs/hep-ph/0601023

by Pran Nath (Northeastern University Boston) and Pavel Fileviez Perez (Lisboa, Portugal) published in Physics Reports as Phys.Rpt..441:191-317, 2007 (needless to say, Phys. Rpt. is a very highly regarded journal of detailed reviews)

says at page 72:

"... a majority of non-supersymmetric extensions of the Georgi-Glashow SU(5) model yield a GUT scale which is slightly above 10^14 GeV. Hence, as far as the experimental limits on proton decay are concerned, these extensions still represent viable scenarios ... it is possible to satisfy all experimental bounds on proton decay in the context of non-supersymmetric grand unified theories. For example in a minimal non-supersymmetric GUT based on SU(5) the upper bound on the total proton decay lifetime is ... 1.4 × 10^36 years ...".

Further, you quoted Lubos as saying:

"... there are five exceptional Lie groups, G2, F4, E6, E7, E8. Only the last three are large enough to play the role of a grand unified group. But among these five groups ... E6 is the only viable grand unified group ... The other groups are inconsistent with the parity violation in Nature - e.g. with the fact that the neutrinos have to be left-handed. ... anyone who claims that he has a grand unified theory based e.g. on E8 is a hack who misunderstands exceptional Lie groups in physics ...".

It is NOT true that E8 cannot be the basis for realistic physics models that are consistent with chirality (i.e. "neutrinos have to be left-handed"). Garrett Lisi's model does that by the possibility that the neutrinos of opposite chirality (i.e., an anti-family of mirror fermions) might be suppressed by interaction with axions and/or some of the Higgs scalars in his model, as Garret states in his recent paper at http://arxiv.org/abs/1006.4908 which paper is a revision of his earlier work that was criticized

by Skip Garibaldi with respect to its math. You might say that Skip Garibaldi helped Garrett Lisi to improve the math structure of his E8 model to its current state, which seems to have been approved by most of the many experts in E8 math who studied it at a Banff workshop http://www.birs.ca/events/2010/5-day-workshops/10w5039

Even I have been able to construct a physically realistic E8 model that is consistent with chirality. As to the mathematical soundness of my E8 model, Skip Garibaldi (a strong opponent of Garrett Lisi's E8 physics) told me by email on 26 April 2010:

"... mathematically what you write looks like completely standard and unremarkable examples of representations of complex semisimple Lie groups. But of course your point is about the physics interpretations of these things, and unfortunately I have no hope of understanding that side of it because of my lack of knowledge of physics. I only got to the point of writing something about Lisi's thing because of the false mathematical statements in his arxiv note ..."

I short, even Skip Garibaldi agrees that my math is sound, and does not go one way or the other on the physics. As I said above, Skip Garibaldi's criticism led Garrett Lisi to clean up the math in his E8 model. An outline of my E8 model is on the first page of http://www.valdostamuseum.org/hamsmith/E8CCTS12a.pdf with many further details in the rest of that paper

and in other papers on my web site.

It is pathetic that Lubos is unaware of work such as that of Pran Nath which is available in the respected journal Physics Reports, and that Lubos fails to understand the subtleties of how E8 models can actually be constructed consistently with physical chirality, and it is tragically sad that he seems to be unaware of the extent of his own ignorance.

Tony

On Nov 20, 2010, at 5:07 PM, Saul-Paul Sirag wrote:

Jack, Tony, et alia:

It's a good thing that the LHC is up and running. It may be that we will know in a few years which approach to TOE is the right one. I am partial to the string theory approach, as most recently described in Gordon Kane's article, "String Theory and the Real World" (Phys. Today, Nov 2010). This theory requires (among other things) supersymmetry partners, some of which might show up at the LHC. The article by Garrett Lisi and James Weatherall, "A Geometric Theory of Everything" (Sci. Am., Dec 2010), mentions (among other things) the prediction of "mirror fermions" (which would have to be more massive than their mirror partners). Will these show up at the LHC? These mirror fermions are Lisi's main reply to the Distler&Garibaldi critique:

Given this explicit embedding of gravity and the Standard Model inside E8(−24), one might wonder how to interpret the paper “There is no ‘Theory of Everything’ inside E8.”[7] In their work, Distler and Garibaldi prove that, using a direct de- composition of E8, when one embeds gravity and the Standard Model in E8, there are also mirror fermions. They then claim this prediction of mirror fermions (the existence of “non-chiral matter”) makes E8 Theory unviable. However, since there is currently no good explanation for why any fermions have the masses they do, it is overly presumptuous to proclaim the failure of E8 unification – since the detailed mechanism behind particle masses is unknown, and mirror fermions with large masses could exist in nature. Nevertheless, it was helpful of Distler and Garibaldi to emphasize the difficulty of describing the three generations of fermions, which remains an open problem.

arXiv:1006.4908v1 [gr-qc] 25 Jun 2010

Of course string theory has since 1985 been using E8 x E8 as the symmetry of one of the two Heterotic string theories. In this theory spacetime is higher dimensional, i.e. with 10 + 16 = 26 dimensions. The compactification of the extra dimensions (in order to arrive at a 4-d spacetime) entails a symmetry breaking of E8 to E6 (which avoids mirror fermions). As you know my own approach is what I call ADEX theory (the study and application of all the A-D-E Coxeter graphs). So whatever approach to E8 is favored by nature, this will be only a piece of the A-D-E complex.

All for now;-)

Saul-Paul

----------------------------

On Nov 20, 2010, at 2:22 PM, JACK SARFATTI wrote:

Saul-Paul

What is your assessment of the situation?