Well, silly string theory, with its 7 of its 11 dimensions by definition being UNTESTABLE ... I guess that is NOT supernatural ... because it IS accepted as science? Wow.
String theory as a whole is not in principle untestable, however. There are various particles that should appear in high energy particle accelerator experiments, for example. If no particles or particles different from those predicted appear in such experiments, then string theory is wrong. Furthermore, it may be possible (but admittedly difficult) to test for the presence of the additional dimensions predicted by string theory. At macroscopic distances, gravity obeys an inverse square law. This is a direct result of the fact that there are three macroscopic spatial dimensions. Were there 7 macroscopic spatial dimensions, gravity would obey an inverse sixth power law. By testing at microscopic dimensions, it may be possible to determine that gravity obeys a force law different from an inverse square law which would be evidence of extra microscopic spatial dimensions.
Any physicist will tell you that string theory has not been experimentally confirmed; and it is still controversial, even among many physicists; it's not a very good parallel to the Theory of Evolution (string theory still in its relative infancy).
A better comparison in particle physics would be the Standard Model, which has many abstract aspects & requires some minor tinkering to accomodate new data, but is well-verified experimentally and accepted by virtually the entire physics community, even though some of the particles it requires (e.g. gluons) have never been observed directly (though their effects have).