The "exceptionally simple theory of everything," proposed by a surfing physicist in 2007, does not hold water, says Emory University mathematician Skip Garibaldi.

Garibaldi did the math to disprove the theory, which involves a mysterious structure known as E8. The resulting paper, co-authored by physicist Jacques Distler of the University of Texas, will appear in an upcoming issue of *Communications in Mathematical Physics*.

"The beautiful thing about math and physics is that it is not subjective," says Garibaldi. "I wanted a peer-reviewed paper published, so that the scientific literature provides an accurate state of affairs, to help clear up confusion among the lay public on this topic."

In November of 2007, physicist Garrett Lisi published an online paper entitled "An Exceptionally Simple Theory of Everything." Lisi spent much of his time surfing in Hawaii, adding a bit of color to the story surrounding the theory. Although his paper was not peer-reviewed, and Lisi himself commented that his theory was still in development, the idea was widely reported in the media, under attention-grabbing headlines like "Surfer dude stuns physicists with theory of everything."

Garibaldi was among the skeptics when the theory hit the news. So was Distler, a particle physicist, who wrote about problems he saw with Lisi's idea on his blog. Distler's posting inspired Garibaldi to think about the issue more, eventually leading to their collaboration.

Lisi's paper centered on the elegant mathematical structure known as E8, which also appears in string theory. First identified in 1887, E8 has 248 dimensions and cannot be seen, or even drawn, in its complete form.

The enigmatic E8 is the largest and most complicated of the five exceptional Lie groups, and contains four subgroups that are related to the four fundamental forces of nature: the electromagnetic force; the strong force (which binds quarks); the weak force (which controls radioactive decay); and the gravitational force.

In a nutshell, Lisi proposed that E8 is the unifying force for all the forces of the universe.

"That would be great if it were true, because I love E8," Garibaldi says. "But the problem is, it doesn't work as he described it in his paper."

As a leading expert on several of the exceptional Lie groups, Garibaldi felt an obligation to help set the record straight. "A lot of mystery surrounds the Lie groups, but the facts about them should not be distorted," he says. "These are natural objects that are central to mathematics, so it's important to have a correct understanding of them."

Using linear algebra and proving theorems to translate the physics into math, Garibaldi and Distler not only showed that the formulas proposed in Lisi's paper do not work, they also demonstrated the flaws in a whole class of related theories.

"You can think of E8 as a room, and the four subgroups related to the four fundamental forces of nature as furniture, let's say chairs," Garibaldi explains. "It's pretty easy to see that the room is big enough that you can put all four of the chairs inside it. The problem with 'the theory of everything' is that the way it arranges the chairs in the room makes them non-functional."

He gives the example of one chair inverted and stacked atop another chair.

"I'm tired of answering questions about the 'theory of everything,'" Garibaldi says. "I'm glad that I will now be able to point to a peer-reviewed scientific article that clearly rebuts this theory. I feel that there are so many great stories in science, there's no reason to puff up something that doesn't work."

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**More information:**
Paper: http://arxiv.org/abs/0905.2658

## Slotin

http://en.wikiped...er_group

## jonnyboy

## Shootist

True. But given E8's origin my money is on Mr. Garibaldi.

## thermodynamics

## Slotin

## frajo

## wimpy

"Peer review" does not equal fact!

Lisi sent in a testable theory, and if this paper holds up that's great! We can move on to other theories.

And "frajo" "PERFECT scientific thinking based on the falsifiability of scientific theories."

"PERFECT" "frajo" "PERFECT"!

I hate to see that word even used anywhere near physicists! And since when has "string theory" been "falsifiable"!

## frajo

## seneca

http://mathworld....ing.html

Therefore the E8 Lie group answers the trivial question: "Which structure should have the tightest lattice of particles, exchanged/formed by another particles?". And such question has perfect meaning even from classical physics point of view! Such question has a perfect meaning in theory, describing the most dense structure of inertial particles, which we can ever imagine, i.e. the interior of black hole.

## seneca

http://www.pnas.o...full.pdf

This model considers, the current Universe generation is formed by interior of giant dense collapsar, which is behaving like black hole from outer perspective. This collapse was followed by phase transition, which proceeded like crystallization from over-saturated solution by avalanche-like mechanism. During this, the approximately spherical zones of condensing false vacuum (branes) have intersect mutually, and from these places the another vacuum condensation has started in sort of nucleation effect.

Now we can observe the residua of these zones as a dark matter streaks and the dodecahedron structure of these zones should correspond the E8 group geometry, as being observed from inside.

## seneca

The schematic division of theories into good and wrong one doesn't work well here. At the moment, when such theory can predict something relevant about particle generations, it cannot be completely wrong - but it shouldn't be overestimated as well. Such theory is simply just another tool for Universe understanding and its relevancy can be only measured by number of theorists, which will extrapolate it further.

## hush1

http://www.techno...v/24975/

Unless you can convince mathematicians (or at least obtain a consensus) that there is no such concept as non-applicable (pure) mathematics, the rest of science's grand unifying efforts will remain forever in limbo. And such an attempt, to convince the mathematical society, is being made with the research cited above.

Even if all humans were omni-linguistic - capable of all human language - past and present - rendering translation obsolete - interpretations remain for all other languages outside the human language - the language of all other living entities and Nature itself.

Does information increase entropy?

## Slotin

This article contains just a few abstract ideas and equations - with compare to Garrett's E8 model, which is fully fledged theory of many particle generations.

## hush1

So? What is your point? Perhaps one is incomplete - still in limbo. Garrett's Model is as close as you can get to DOA - pending peer review. After which, it will be.

## seneca

## seneca

In such a way, E8 is a heavy weight between existing theories, because every opponent of it must be able to explain at the same moment, if this theory is wrong, why it fits properties of two hundreds particles so well. Because the very beautiful thing on math is, despite of what is saying or not, experiment always goes first.

Frankly, I wouldn't want to be at Diestler or Garibaldi place by now...

## hush1

String theory went through the same evolution, it was full of anomalies - mathematical inconsistencies. Now string theory is mathematically consistent. A consistent mathematical model. String theory's next step is to make it accessible to the scientific community through scientific method - a method that describes, along with other things, that falsifiability is essential to the scientific method.

This is why string theory waits and waits and waits - and not because it is not mathematically

inconsistent.

I would do ANYTHING to be in Diestlers' or Garibaldis' places right now. And Garrett should too.

There are no 'opponents' here. I see none.

## broglia

Regarding E8 theory, if some theory fits less or better properties of 226 particles at the same moment, it simply cannot be completelly wrong - despite its formulation can suffer some inconsistencies. Problems in formulation can be corrected anytime latter. The REAL problems for E8 would occur, if E8 would violate some well known experiments. I presume, the fact, E8 is not a TOE is apparent for everybody, because our Universe simply doesn't appear like root system of E8 group - it's much more irregular.

## seneca

http://www.fqxi.o...opic/627