Of all social institutions, language is least amenable to initiative. It blends with the life of society, and the latter, inert by nature, is a prime conservative force. Greek philosopher aristotle described sentences as having a logical organization made up of parts of speech, such as subject and predicate, each one with a specific referential function. So, the subject of a sentence is part of a proposition about which a statement is made, whereas the predicate is what is affirmed or denied concerning a proposition. Thrax"s terms are used to this day in linguistics and grammar study generally. In antiquity the notion that good grammar also emerged, referring to a use of language that mirrored elegance in speech and logical thinking. It was a metric of social achievement, and still is. Grammar (previous chapter), by claiming that all languages possessed the same set of sentence-making principles that were applied to the construction of specific grammars.