von Neumann said mathematics is "relationships about relationships"
I think of it as the art of "making representations and reasonings"
However, as with all languages, it is hermetic: it can only deal with things in itself. Science is the relationship between "what's out there?" and what we can devise to *represent* what we think is out there, drawn as much as possible from actual phenomena.
Metamath is fun because it can parallel the scientific process within the hermetically sealed universes of representations using mathematical representations themselves as phenomena (and with much less noise than the physical universe presents to us).
Cheers,
Alan