We live in a universe that can be described by mathematics. There are many mathematical theories, from the standard model to superstrings, and it is hard to figure out which is correct. Which one predicts that the speed of light is 300 million meters per second, or that the ratio of the circumference of a circle to its diameter is 3.14159..... among literally hundreds (thousands?) of other constants and relationships that seem to be set into the fabric of the universe without any causal mechanism. Which theory is correct?

I think they are all correct, but some manifest themselves and others don't. We evolved because our universe has just the right constants to allow us to evolve. Did it do this after an infinite number of failed attempts? Or do all possibilities exist superimposed on each other and only our mathematical group produces a self-consistent, self-aware subset? Still more curious is the question of whether we can use some subset of our reality to build machinery that can probe alternative groups, or are we inherently restricted by the built-in life-supporting relationships to explore just our own mathematical realm.

Still thinking about that one.