A proposition is a symbol in which the representative element, or reason, is left vague and unexpressed, but in which the reactive element is distinctly indicated. In driving along the road with a compagnon, he points at a house and remarks, “That is a pretty house.” It is a proposition. But I make a voyage to a distant island and repeat the remark, “That is a pretty house.” “What house,” asks my interlocutor. “Oh, a house far way.” He will be right in telling me that I do not enunciate anything at all, because I do not indicate what I am talking about.
http://www.commens.org/dictionary/entry/quote-existential-graphs-4