" Tiffany’s Second Thoughts said: Hang on, was that a First Thought? And Tiffany thought: No, that was a Third Thought. I’m thinking about how I think about what I’m thinking. At least, I think so. Her Second Thoughts said: Let’s all calm down, please, because this is quite a small head. "

― Terry Pratchett , The Wee Free Men (Discworld, #30; Tiffany Aching, #1)