What your character thinks is shown in everything she says. She may be proving or disproving some particular point or enunciating some universal proposition. All these comments reveal her personality. Her remarks also show her moral purpose. There are things she wants to talk about or things she wishes to avoid.
Don’t confuse the reader by having your character talk about something that has absolutely no relevance to the story. Everything said must be relevant, revealing the character’s motivation, experience and attitude.