Although humor is a phenomenon experienced by most humans, its exact cause is a topic of heavy debate. There are many theories of humor which attempt to explain what it is, what social functions it serves, and what would be considered humorous. Although various classical theories of humor and laughter may be found, in contemporary academic literature, three theories of humor appear repeatedly: relief theory, superiority theory, and incongruity theory.[1] These theories are used as building blocks for the rest of the theories. Among current humor researchers, there has yet to be a consensus about which of these three theories of humor is most viable.[1] Some proponents of each theory originally claimed that theirs, and theirs alone, explained all cases of humor.[1][2] However, they now acknowledge that although each theory generally covers its area of focus, many instances of humor can be explained by more than one theory.[1][2][3][4] Similarly, one view holds that theories have a combinative effect; Jeroen Vandaele claims that incongruity and superiority theories describe complementary mechanisms that together create humor.[5]