Gross Calls String Theory A Bizarre Science That Is A Dangerous Business

Demystifier

As I already said once, asking string theory to explain the Standard Model of "elementary" particles is like asking quantum electrodynamics to explain life on Earth.

arivero

Are you intending to be ironic or is it a defense of the anthropic principle?

Let me do my try:

"asking Planck scale string theory to explain the Standard Model of "elementary" particles is like asking QCD scale string theory to explain gravity".

Demystifier

It is a sort of the defense of the anthropic principle. More precisely, it is an argument that it is quite natural that a fundamental theory contains a huge number of different solutions, so that it cannot really explain why we live in a very specific solution in which we live. A "theory of really everything" should be also a theory of the initial conditions, which string theory is certainly not supposed to be.

arivero

Indeed it seems that the label "Theory Of Everything" implies, to laymen, more than the strict goals of understanding the Standard Model and -perhaps- gravity. The old label "Grand Unified Theories" was perhaps more concrete: we are interested on the "guts" of the animal, no more.

wolram

I am sure there must be some value in all this across the garden fence chit chat, or you very cleaver guys would not be indulging in it but , does it solve anything?

Addition

I can remember when we had engineering meetings to resolve a problem, they proved quite useless, it was found that a single observation, of one guy solved the problem.

Sauron

Well, Lubos Motl and Jackes Distler are totally agianst landscape and they publish routinatelly in their journals about it. I guess they are, at least, relativelly prominent figures. There is also something called "Swampland", a program initiated by horava (or another well known figure in strng theory, I have no time now to verify it) which is something like a program against landscape consisting in the search for selfconsistency of low energy effective field theories with the full strig theory. This puts more realisitic limits amount the really obtenaible vacua.

The two more recent books on string theory, Michel dine "Supersimmetryand string theory" and Becker, Becker, Schwartz: "string theory and M-theory" have an introduction to the landscape but they are very coutous about it´s actual convenience. I wouldn´t say that the string landscape could be considered a signature of the viewpoints of most people working in string theory (fourtunatelly).

ccdantas

A theory of everything is not expected to be a theory of contingency (I do not see a meaning for the latter, btw). There are many solutions (different orbit configurations) for the gravitational problem. The fact that, e.g., Mars currently has a given orbit does not depend on any intrinsic necessity, it is purely contingent. But the fact that its orbit fits an ellipse indicates the acceptability of Newtonian gravitational theory as a correct description of the physical phenomenon involved (under the domain of validity of the theory). What is the theory that "shapes" the masses of particles?

turbo

Quite a penetrating observation, Christine - not that I'd expect less of you. The fact that an ad hoc modification of Newtonian gravitation (MOND) has predictive power that correctly described the gravitational behavior of low-surface-brightness galaxies a decade before their observation illustrates that theory can be made to conform to observation. In no way does it address the foundational physics, though, so though that modification appears to work in galactic domains, we still don't know why. At least MOND works for a broad range of spiral galaxies, and that range of applicability (generalization) is promising, though I expect that the modification addresses some foundational physics that is as-yet not understood.

Somehow, I'm always drawn to the LQG side of the force (cheesy Star Wars reference) because there are hints (including recent MAGIC observations of possible energy-dependent variable c) that the LQG folks are on a productive path, especially in regard to describing some fundamental quality(ies) of space. In comparison, String appears allegorical and hard to pin down. I know it is popular and well-funded, but the engineer in me wants mechanics based on observables.

arivero

The point is that the masses of the particles are known to be suspiciously regular, with exactitudes beyond the law of low numbers or the birthday paradox. So it is hoped that there is some theory shaping the masses.

String theory aimed to this niche two times: first at QCD energies, and then going up to Planck but claiming contact with GUT theories and renormalization group running from high to low energy. And due to he closeness between Planck scale and GUT scale, for sure every theory of quantum gravity tries to claim some possibility to fix the masses. I think it is a bad idea; in the low energy regime almost everything points to the electroweak scale, the only two exceptions being 1) The GUT running of coupling constants and 2) the neutrino seesaw scale.

Fra

So, lets say we looking for a theory. Then one can ask what is the method that shapes our theories? Then we are apparently looking for a theory of the evolving theories, aren't we?

Or is everyone satisfied with the ad hoc method, combined with the falsification selection method?

Opinions?

/Fredrik