The propositional sign consists in the fact that its elements, the words, are combined in it in a definite way.

The propositional sign is a fact.

3.141    The proposition is not a mixture of words. - (Just as the musical theme is not a mixture of tones.)

The proposition is articulate.

3.142    Only facts can express a sense, a class of names cannot.

3.143 (2)    That the propositional sign is a fact is concealed by the ordinary form of expression, written or printed.

For in the printed proposition, for example, the sign of a proposition does not appear essentially different from a word.

(Thus it was possible for Frege to call the proposition a compounded name.)

3.144    States of affairs can be described but not named.