The cornerstone of semiotics, the sign, is composed of the perceptible signifier and the intelligible signified. The visual and tangible thing chair is a signifier and the intelligible thought chair is a signified. Together they combine to produce a sign chair .
Language is defined as a system of signs - any system of signs is therefore a language.
Semiotics is defined as the science of signs. It is especially interesting therefore to discover that for George Boole, the founder of Boolean algebra, sign is a key concept in the instigation and development of his algebra. Boole establishes his mathematical theory on foundations intimately connected with language and its structure. An examination of the relevant conceptual exposition shows that Boole s sign is identical to the sign described by Saussure. Literal symbols, as x, y, z, representing things as objects of our conceptions.