Asking for a way to falsify a theory is crucial. On this case I think we need to look for falsifiable predictions the theory makes that then can be disproven. If a theory makes no falsifiable predictions it's useless. So slightly backwards, it seems in this case, asking for how to proof it is closer to asking "what predictions does this theory make?".
A theory that's not disprovable isn't valuable. See Russel's tea pot.
How would you prove that though?