The ridiculous is that which is highly incongruous or inferior, sometimes deliberately so to make people laugh out of their minds or get their attention, and sometimes unintended so as to be considered laughable and earn or provoke ridicule and derision. It comes from the 1540s Latino "ridiculosus" meaning "laughable", from "ridiculus" meaning "that which excites laughter", and from "ridere" meaning "to laugh". "Ridiculous" is an adjective describing "the ridiculous".In common usage, "ridiculousness" is used as a synonym for absurdity or nonsense. From a historical and technical viewpoint, "absurdity" is associated with invalid argumentation and reasoning, "nonsense" with semantics and meaning, while "ridiculous" is most associated with laughter, superiority, deformity, and incongruity. Reductio ad absurdum is a valid method of argument, while reductio ad ridiculum is invalid. Argument by invective declaration of ridiculous is invalid, while arguments involving declarations of nonsense may summarize a cogent semantic problem with lack or meaning or ambiguity.Historically, the ridiculous was central to initial theories of humor and laughter as first put forth by philosopher Thomas Hobbes. It was used in psychosocial power struggles in the European court by reducing opponents to the ridiculous using ridicule. It is currently used in the theory of humor to create laughter, shock, parody, or satire. Reactions to the ridiculous have been studied in psychology for its effects on memory, attention, and attitude in social hierarchies. These studies have been applied to the theory of advertisement regarding attention, memory, and alleviation of preexisting negative attitudes toward products. The ridiculous is often contrasted with the sublime, one of extreme inferiority, the other of extreme superiority, and often one can suddenly move from one extreme state to the other.