This is a criticism commonly leveled against Superstring Theory and its approach to gravity. There are two books essentially accusing it of being theological rather than scientific in nature.

I reviewed them here a few years ago: http://www.ribbonfarm.com/2007/0...

It's not the mathematics being formidable that matters. Lots of science has equally forbidding mathematics (try solving the Navier-Stokes equations, which is Newton's Laws level stuff, for the general planetary weather system..). Most science cannot be understood by 99% of humanity. What matters is unfalsifiability.

You can have completely rigorously mathematical ideas that are unfalsifiable, and completely non-mathematical ideas that are falsifiable.

Math is orthogonal to a falsifiability-based notion of truth.

Theology can be mathematical. The most famous example is of course Pascal, who convinced himself that he should be religious via the following mathematical argument:

1. Either God, Heaven and Hell exist, or they do not. There is some probability associated with each case.

2. If they do, and I don't believe, Hell is infinitely painful, and has infinitely negative utility.

3. So no matter how small the probability that G/H/H exist, the infinite negative utility of non-belief, and the infinite positive utility of making it to heaven makes it rational to believe.

People have since refined this argument quite a lot. Mostly just for the hell of it.