The word theory is used differently in science to how it is in common speech. In science, a “theory” represents humanity’s best possible explanation for something given everything we know. For example, the theory of gravity gives a reason for why things are attracted to each other, namely the bending of spacetime.
Theories don’t become laws, either. Laws in science describe what happens, and theories describe how. To go back to gravity, the law of gravity is an equation that can tell you exactly how much two objects will be attracted to each other, but it can’t explain how that happens. That’s what the theory is for.
Hope this helps!
Hollow Knight; I’m playing it for the first time and I’ve progressed enough to get the true ending, but I’m going to do some of the side content before I do. Probably not 100%ing, I’ve already struggled to get this far, but I’ll try to get every charm and finish the Troupe before finishing off my playthrough. It’s a great game, and I’m definitely excited to play Silksong, if that manages to release within my lifetime.