Math is a way to create abstract, self-consistent models of reality. It's not really an issue of "does this equation describe reality" as is the question "does this equation allow us to make predictions about the future?" If it does, it's a useful tool in itself.

There's really nothing quite like math for being able to predict the future. Without it, you're back to the pre-scientific method of determining "truth", and you might as well go back to trying to use sheep's entrails to predict the orbits of the planets.

Rob