It’s important to keep in mind as you study chemistry or any other science that scientific theories are not laws of nature and can never be absolutely proven. There’s always the chance that a new experiment might give results that can’t be explained by present theory. All a theory can do is to represent the best explanation that we can come up with at the present time. If new experiments uncover results that present theories can’t explain, the theories will have to be modified or perhaps even replaced.
— John E. McMurry, Chemistry 7th Edition