Textbooks tell you that an independent clause must have a subject, verb and express a complete thought (or stand alone). However, I'm confused why the following examples below are considered to be independent. Yes, they contain a subject-verb set but don't seem to be a complete thought. Actually , to me, they seem to be dependent on the dependent clause to be make sense instead of the other way round. Can someone please clarify this for me so that I can explain it to a gentleman that I am volunteering with.
I realized that he had made a mistake. [realized what?]
He said that he was tired. [said what?]
He said and I realized certainly don't seem to be sentences in my opinion.