6.12 That the propositions of logic are tautologies shows the formal – logical – properties of language, of the world.
The fact that its parts connecting together just so gives a tautology characterizes the logic of its parts.
For propositions, connected in a specific way, to make a tautology, they must have specific structural properties. That they [do] make a tautology when so connected shows therefore that they [do] have these structural properties.
I translate bestimmte as ‘specific,’ where P&McG have ‘certain’ and Black (p. 321) suggests ‘determinate.’ ‘Definite’ might be good too.
What properties? It’s all grammar isn’t it, arbitrary? So are the formal properties of the world arbitrary too? Maybe. They are (only) formal, after all.