The general propositional form is the variable: 'It is thus and so'.

We now state the most general form of a sentence. That is, we describe sentences in any notation whatsoever so that every possible sense can be expressed by a symbol fitting that description, and so that every such symbol can make sense, once appropriate meanings of the names are chosen. It is clear that the description of the most general propositional form should only include what is essential - otherwise it would not be the most general form.

That there is a general form of a sentence is proved by the fact that there is no grammatical sentence whose form it did not allow us to foresee (i.e. derive). The general form of a sentence is: It is thus and so.

Suppose that all elemental propositions are given. What propositions can one construct with them? That would be all propositions and that is their limit. Propositions are all that follows from the entirety of elemental propositions (and, of course, from its being all of them). In a certain sense, it could be said that all propositions were generalizations of elemental propositions. The general propositional form is a variable.