The scientific method says that if experiments or observations falsify a theory, that theory must be rejected. String theory requires space to have 9 dimensions. But observation shows that our space has only 3 dimensions. This alone should falsify string theory. I know that scientists have amended an ad-hoc hypothesis that 6 of the dimensions are curled up too tiny to observe. But there is no experimental evidence of this. And the theory does not predict or explain why 3 dimensions should be large and 6 tiny. If you add enough ad-hoc hypotheses, any theory could be accepted. The Earth-centered universe could still be believed if you add enough epicycles and other unsupported ideas to explain the motion of the planets. But science usually rejects this kind of fixing up of a theory (mainly due to Occam's Razor). So, without ad-hoc hypotheses, shouldn't string theory also be rejected? Does any future experiment even have the potential to falsify string theory? If so, what might that experiement be? If not, then string theory is not science. It is a religion.