"The universe we live in is one great mystery. Until that mystery is solved, theorizing God, Strings or refusing to Theorize at all is all about the same. Either way, you are stuck in an absurd mystery, and there's not a lot you can do about it. Except Theorize. Or not. "One hundred years ago, one might have made a similar statement regarding relativity. But the effects of relativity were soon experimentally verified. Indeed, before Arthur Eddington tested Einstein's theory of general relativity via the bending of star light during a solar eclipse, the latter was asked what he would think if Eddington's measurements failed to support his theory, Einstein replied "Then I would have felt sorry for the dear Lord. The theory is correct."
During subsequent decades one might have made a similar statement regarding quantum mechanics. Yet we can observe many quantum phenomena, such as quantum strangeness (Feynman included the double slit experiment as one example), entanglement (action at a distance), etc.
Relativity and quantum mechanics are still mysterious and non-intuitive, and perhaps will always be. Yet we take for granted practical applications that utilize both of these ideas, such as GPS units and devices that rely on electron tunneling (VLSI chips, microscopes, etc.)
Using string theory is a red herring, since it is a theory in its infancy, is currently untestable, and may in fact have no predictive value!
Gideon's error is that God is simply not a scientific postulate. It is not predictive, nor is it falsifiable. Even the argument "Does God exist?" is framed as an evidence-based argument, for when we use the term "exist" we generally mean something along the lines of "is it testable via scientific means". God is a faith-based idea, and thus a pure materialist has no basis for believing in God.