English was not engineered from the ground up to be sensible and consistent. Instead it evolved slowly over time, as new things got tacked on year after year, and other things died out or drifted in pronunciation.

Here's what Middle English sounded like:

"Whan that Aprille with his shoures soote, The droghte of March hath perced to the roote, And bathed every veyne in swich licóur Of which vertú engendred is the flour."

-Chaucer's Canterbury Tales

I think this is straight forward. In our everyday life laws aren't derived from something else either. They just are. And OP seemed to have a hierarchical view of them as well. They were just under the assumption that a theorem could be "promoted".

I guess a real-life analogy would be a judge making a ruling under some laws. That would make a precedent in many countries but not a law. If then a new law were passed it could invalidate that precedent similar to someone disproving a theorem.