Freud's work on humor must be mentioned in any treatment of the subject. I will merely mention it, however. The present theory points to a number of empirical questions which are not answered here: What are the things that people care about? and How strong are these commitments? What is the list of violations of what some individual cares about? What counts as ``normal'' for people in general and for different kinds of people? What is the structure and content of the whole psychological realm of affect? Freud's work, including his classic studies of humor (1905/1960, 1927/1961), explores these questions.
For example, he distinguishes between ``innocent'' and ``tendentious'' jokes, where tendentious jokes have a sexual or aggressive content, and are capable of eliciting howling laughter, while innocent jokes have less emotional impact, and elicit just a smile or a chuckle or less. Freud relates this difference to the fact that sexuality and aggression are strong and fundamental human affects. Or Freud's (1927/1961) paper, for example, concerns the effects of certain kinds of comical interpretations on psychic energies in id, ego, and super-ego. The term, ``humour'', in fact, is restricted in Freud's terminology to comic interpretations based in the super-ego, while ``jokes'' (``Witz'' in German) are based in the unconscious (1961 edition: p. 165). That work is not about the structure of humor perception; instead, it is about the effects of humor perception on human emotional life and its interaction with his theory of psychological architecture.
Freud's psychological work on humor thus focusses on the questions mentioned above. But those questions are quite distinct from, the question, What is humor?, which is the focus of the present paper. Thus Freud's analysis of humor is not at the level of the present paper, and it is beyond our scope to review Freud's discussion of these other issues, here.