[sev0]

"Law" can also be used for pithy statements that don't have to be particularly rigorous. C.f. Murphy's Law.

[K0SM0S]

This statement generalizes quite well all around the world to the other kind of law, that's voted in parliament/congress... haha! ;-)

More seriously, I think the word OP is looking for is theory. Nuggets aren't theory, they're really empirical by essence — observations.