Without, yet, so much as a single experiment to prove (or, disprove) the existence of "strings", how have "strings" speculations graduated, from "hypothesis", all the way to "theory" (i.e., why is the model not called the "strings hypothesis") ?

 

String Theory has yet to make novel experimental predictions at accessible energy scales, leading some scientists to claim that it cannot be considered a part of science

 

Scientific Method

 

Without, yet, so much as a single experiment to prove (or, disprove) the existence of "strings", how have "strings" speculations graduated, from "hypothesis", all the way to "theory" (i.e., why is the model not called the "strings hypothesis") ?

 

They haven't.

 

In a sense "string theory" is intended to convey the impression of a mathematically consistent a la, say, Galois theory. In mathematics "theory" has a somewhat different meaning that in science, since the test of a mathematical theory is logic rather than experiment.

 

Unfortunately string theory is not well-defined in the mathematical sense either. No one can rigorously tell you precisely what string theory is. Nor has it produced a new testable prediction.

 

So when the word "string" is used in a title as an adjective, one requires a noun that it modifies, and "theory" more or less pops up as a knee jerk reaction. It can't be a hypothesis, since there is no hypothesis in evidence to be tested or evaluated. "Fantasy" seem unduly pejorative in this situaation since on the surface the idea has promise. And the practioners have too much personal investment to be willing to call it a "wild ass guess".