Full Idea
A proposition must use old expressions to communicate a new sense.
Gist of Idea
Propositions use old expressions for a new sense
Source
Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.03)
Book Reference
Wittgenstein,Ludwig: 'Tractatus Logico-Philosophicus (Pears)', ed/tr. Pears,D. /McGuinness,B. [RKP 1961], p.22
A Reaction
A nicely expressed affirmation of the principle of compositionality. It entails that the propositions can be either true or false, according to LW.