“The notion ‘grammatical’ cannot be identified with ‘meaningful’ or ‘significant’ in any semantic sense. Sentences (1) and (2) are equally nonsensical, but…only the former is grammatical.
(1) Colorless green ideas sleep furiously.
(2) Furiously sleep ideas green colorless.
Excerpted from: Schapiro, Fred, ed. The Yale Book of Quotations. New Haven: Yale University Press, 2006.