Zettel is a collection of assorted remarks by Ludwig Wittgenstein. It contains several discussions of philosophical psychology and of the tendency in philosophy to try for a synoptic view of phenomena.[1] Analyzed subjects include sense, meaning, thinking while speaking, behavior, pretense, imagination, infinity, rule following, imagery, memory, negation, contradiction, calculation, mathematical proof, epistemology, doubt, consciousness, mental states, and sensations.[2]