just some of the theories I believe don't.
Theories are not guesses. They're not some guy smoking a bowl and saying "HEY GUYS CHECK THIS OUT". Theories are backed by research and evidence, theories are backed using the scientific method. Gravity, for example, is a theory. We understand that it works, we vaguely know how it works, but we don't absolutely know 100% for sure how it works. The same is essentially true for other theories, like evolution.