A number of competing theories have been written. For Aristotle, we laugh at inferior or ugly individuals, because we feel a joy at being superior to them. Socrates was reported by Plato as saying that the ridiculous was characterised by a display of self-ignorance. Schopenhauer wrote that it results from an incongruity between a concept and the real object it represents. Hegel shared almost exactly the same view, but saw the concept as an "appearance" and believed that laughter then totally negates that appearance. For Freud, laughter is an "economical phenomenon" whose function is to release "psychic energy" that had been wrongly mobilised by incorrect or false expectations. Philosopher John Morreall theorises that human laughter may have its biological origins as a kind of shared expression of relief at the passing of danger. The General Theory of Verbal Humour (GTVH) proposed by Victor Raskin and S. Attardo identifies a semantic model capable of expressing incongruities between semantic scripts in verbal humour; this has been seen as an important recent development in the theory of laughter. Recently Peter Marteinson theorised that laughter is our response to the perception that social being is not real in the same sense that factual states of affairs are true, and that we subconsciously blur the distinctions between cultural and natural truth types, so that we do not normally notice their differing criteria for truth and falsehood. This is an ontic-epistemic theory of the comic (OETC). Robert A. Heinlein's view of why people laugh is explained in one of his most praised novels, Stranger in a Strange Land, "because it hurts", is empathic but also a release of tension.