Why can't the standard model be a theory of everything?

[arivero]

Which are the arguments against considering the possibility of the Standard Model as a TOE. Why do we need more particles or more degrees of freedom?

It lacks, of course, a mechanism to get the SM from geometric considerations, or to get geometry from the SM. But it is almost a minor nuissance.

 

[selfAdjoint]

The SM can't be the TOE because it doesn't do gravity. Gravity is surely part of "everything".

 

[downh]

Yeah!
That is the key problem.

 

[arivero]

I was admiting it : It lacks, of course, a mechanism to get the SM from geometric considerations, or to get geometry from the SM. But the SM plus such a mechanism should be already a complete TOE.

 

[selfAdjoint]

There's been some argument on sci.physics.research about whether a quantum system, such as the standard model, melded with a classical system, such as general relativiy, can be consistent. Some people have claimed to prove NO, but it seems their proofs aren't as strong or comprehensive as they believe.

So maybe it's true, meld the geometry of GR with the quantum SM and it explains everything that really needs explaining. It has some holes in it maybe - the masses and interaction strengths of the particles in SM, which have to be put in by hand (something like 19 numbers IIRC), and the fact the energy is not well-conserved in GR, but all in all it would serve.

The problem is to do it. An awful lot of smart people have tried to do this trick over the past 5 or so decades, starting with Einstein himself. Nobody has shown a really good melding yet.