A thought is a sentence that makes sense.

A sentence is an image of reality: for if I understand a sentence, I know the situation that it represents and I understand it without having had its sense explained to me. It shows its sense, it shows how things stand if it is true; and it says that they do so stand.

A proposition exhibits matters of fact which may be the case or not. The sense of a proposition consists of both correspondence and non-correspondence to matters of fact which themselves can be the case or not.

The truth values of elemental propositions denote the both the possibility that a matter of fact may be the case as well as not. A proposition expresses agreement or disagreement with the truth values of elemental propositions, so the truth values of the elemental propositions making it up are the conditions that determine whether it is true or not.

It now seems possible to give the most general propositional form: "As a matter of fact, this is so."