A mathematician friend of mine once tried to explain some stuff about his field. It started with homomorphisms on Riemann surfaces and then got well beyond my

A mathematician friend of mine once tried to explain some stuff about his field. It started with homomorphisms on Riemann surfaces and then got well beyond my comprehension. Anyway, after he'd been talking for about five minutes he said: "And this has the cardinality of the monster, and no-one knows why." Mathematicians keep finding peculiar and deep relationships between their subfields that, for the most part, are not yet understood. As the article states, a proof isn't really complete until it's comprehensible.