Colorless green ideas sleep furiously

Uncommon card · No. 140171

Colorless green ideas sleep furiously is a sentence composed by Noam Chomsky as an example of a sentence that is grammatically well-formed, but semantically nonsensical. The sentence was originally used in his 1955 thesis The Logical Structure of Linguistic Theory and also appears in his 1956 paper "Three Models for the Description of Language" and his 1957 book Syntactic Structures. There is no obvious understandable meaning that can be derived from it, which demonstrates the distinction between syntax and semantics, and the idea that a syntactically well-formed sentence is not guaranteed to also be semantically well-formed. As an example of a category mistake, it was intended to show the inadequacy of certain probabilistic models of grammar, and the need for more structured models.

Read on Wikipedia · Image Aaron Rotenberg, Public domain