The fields of the standard model explain how forces act at distance by invoking virtual particles called bosons, so the earth’s gravity holds the moon in orbit by graviton particles, and the strong field holds the nucleus together by gluon particles. Hence, according to Feynman:
“A real field is a mathematical function we use for avoiding the idea of action at a distance.” (Feyma,Leighton, & Sands, 1977), Vol. II, p15-7.
For example, if the electro-magnetic field is assumed to emit and absorb photons, that function can explain how charge acts at a distance in particle terms. These photons can’t be seen, as the charge attraction or repulsion uses them up, but they were accepted because photons are known to exist. Essentially, a virtual cause was assumed to explain visible effect, but nothing new was learned about charge. In science, assuming a fact to explain a fact isn’t productive if it doesn’t predict new facts, just as borrowing $10 to make $10 profit isn’t productive. Science advances when theories explain more than they assume, not by making new assumptions for every new fact. The current stagnation of physics can be attributed to this tactic of assuming virtual particles to explain forces, as will be seen.
By analogy, suppose I explain that your tooth was taken by a tooth fairy, maybe a sock fairy took my sock, and a spoon fairy took the lost spoon, but where does this end? These explanations are going nowhere because that every fact has a virtual cause doesn’t predict anything. In the same way, a science based on virtual gravitons and gluons that add no value is also going nowhere.
The best example of this failure to predict is string theory, which tried to explain all physics by field mathematics. The result was so many possible architectures that anything was possible, but no-one could say which one applied. It was mathematically impressive but scientifically useless, so it led nowhere. Based on field theory, it assumed that our space has eight additional dimensions, but they interacted in so many ways that the result was meaningless. According to Woit, string theory is pseudo-science because:
The possible existence of, say, 10500 consistent different vacuum states for superstring theory probably destroys the hope of using the theory to predict anything. If one picks among this large set just those states whose properties agree with present experimental observations, it is likely there still will be such a large number of these that one can get just about whatever value one wants for the results of any new observation. (Woit, 2006), p242.
The basic problem is that inventing a field across all space adds what mathematics calls a degree of freedom to it, so adding many fields is like adding many dimensions to space. Based on current theory, gravity then adds one-dimension, electromagnetism adds two, the strong force adds three, and the weak force two. These eight extra dimensions, plus the three of space, are why string theory has to assume eleven dimensions to work. The failure of string theory to predict anything illustrates why inventing fields isn’t leading anywhere either.
That a universe of eleven dimensions somehow collapsed into ours is a far-fetched idea, akin to the multiverse story. The standard model tactic of inventing new fields to explain new forces is failing because it predicts nothing.