This is the problem String theorists have. We will never, in the lifetime of anybody who guesses we ever existed, be able to build an accelerator powerful enou

This is the problem String theorists have. We will never, in the lifetime of anybody who guesses we ever existed, be able to build an accelerator powerful enough to check whether it is right about gravity. So, they potter and try to show this or that family of variations (among 10^500 imagined) does or doesn't contradict details of the Standard Model we have most confidence in.