Suppose that Natasha says "I am right and you are wrong" to Joey. Natasha's utterance of "I" designates Natasha and her utterance of "you" designates Joey. The truth-conditions of her statement are that Natasha is right and Joey is wrong.

Now suppose that Joey responds by uttering the exact same words back to Natasha: "I am right and you are wrong." He has said the same words, with the same meaning, but he has not said the same thing. Joey's utterance of "I" designates Joey and his utterance of "you" designates Natasha. The truth-conditions of his statement are that Joey is right and Natasha is wrong. Joey has directly disagreed with Natasha.

In this article, "meaning" refers to the rules or conventions that are associated by a language with the expressions in it, the rules that one learns when one learns the language. Given this, the meanings of...