Are you sure about that?
I had the impression that 'law' is an item we can rely on.
It's proven.
Theory is presented as the most likely possibility.
But does not have proof.
Not that some long standing theories are lacking. Some theories are quite firm in appearance, and widely accepted....as if they are proven.
I'm HIV positive about that one. Theories and laws are two separate entities, theories explain and laws describe. A theory can never become a law. And a law can never become a theory, they are just different. It's actually a common misconception. If you go to the website notjustatheory.com it explains it pretty well.