At the small scale, the world is unpredictable. As the scale grows, for well behaved linear systems the law of large numbers kicks in, and you get predictable, mathematical behavior. For complex nonlinear systems, however, the unpredictability of the small scale can "propagate up" and render the system at the large scale completely unpredictable.
Remember that mathematics is just a model, not the territory. For starters, you have incompleteness; for any formal system you can make true statements that are unprovable. Additionally, two constructs which are central to mathematical analysis, infinity and truth, don't exist.
For hundreds of years epicycles were used to model the orbits of the planets. Now we're elevating grand theories that embed the universe in an 11-dimensional manifold.
Remember that mathematics is just a model, not the territory. For starters, you have incompleteness; for any formal system you can make true statements that are unprovable. Additionally, two constructs which are central to mathematical analysis, infinity and truth, don't exist.
For hundreds of years epicycles were used to model the orbits of the planets. Now we're elevating grand theories that embed the universe in an 11-dimensional manifold.