3.4 The proposition determines a place in logical space.
September, 1916, Ludwig gives a typescript copy of his book to Paul Engelmann, a former student of Adolf Loos, and returns with another copy to the Italian front. November, 1916, the Austro-Hungarian empire breaks apart, Wittgenstein is taken prisoner by Italian forces and held at Como, then Cassino, for the next ten months.

In camp he meets Ludwig Hänsel who is instructing in logic the prisoners who want to become teachers after the war. Ludwig becomes his friend, together they read Immanuel Kant's Critique of Pure Reason.

He writes again to Russell, in prison for antiwar activities, sends him and Frege a copy of his new book. Frege: "From the beginning I find myself entangled in doubt as to what you want to say."

LW to Russell: "So my only hope is to see you soon and explain it all to you, for it is VERY hard not to be understood by a single soul."

Russell: "I am sure you are right in thinking the book of first class importance, but in places it is obscure through brevity."

August, 1919, Wittgenstein returns to Vienna, determined to become an elementary school teacher, or perhaps a priest who reads the Bible to children.