Those two are very similar, but are not exactly the same thing.
A thesis is defended or maintained in argument, it is also an unproved statement, it is assumed as a premise.
A preposition is a statement or statement to be debated or discussed. It can also be an informative statement to be evaluated by logic if true or false
So the similarities are there and that's why they're often used as a synonym.
Answer: Pandora's Post by B.K. McSwain. Lillian couldn't believe how out of hand everything had become after her innocuous post, it was only supposed to