Well, but if we're all rephrasing what we hear from someone else, who came up with the thought originally? If we are all repeating, we have to repeat what someone said, we cannot be repeating what no one said. There has to be an origin, and that origin is probably someone, unless you think otherwise.
Correct. It's ingrained into language. The origin of thought is expressed in language. All language is offering definition of words. If you go back to the origin of a term, you most likely will end up having it related to something tangible.