first encounters : sorel and sorel
It was October 1911, volume one of Principia Mathematica was newly out, and Bertrand Russell, fellow of Trinity College, Cambridge, was having his tea when a young man suddenly appeared. He introduced himself as "Loot'vig Vit'gun-shteyne". Russell replied in German, but the young man would have none of that. He had studied engineering, he said in English, but preferred the philosophy of mathematics, and had come to Cambridge expressly to hear Russell on mathematical logic.

Which he did that very day, and throughout the term. He dominated discussions and then followed Russell back to his rooms to press his case, often far into the night. "He thinks nothing empirical is knowable," Russell complained when the Austrian refused to admit, for example, that there was not a rhinoceros in the lecture room, even after Russell had checked under all the tables and chairs. But as Wittgenstein's abilities became more apparent, Russell began to view him as his natural heir in mathematical logic - "the young man one hopes for".

He was - and wasn't. Wittgenstein's intense Teutonic seriousness collided with Russell's mordant wit. When the War came, Wittgenstein enlisted in the Austrian army, ignoring the fact that his friends were on the other side. "The last few days I have thought often of Russell," he wrote from the front. "Does he still think of me?" But lonely nights on watch could be productive, and during a lull in the fighting, he put the Tractatus on paper. He finished it just before his capture by the Italians.

The War changed Wittgenstein. A logical mysticism pervaded his thinking and seeped into the Tractatus, as in its concluding line: "Whereof one cannot speak, thereof one must be silent." Russell did not much like the Tractatus, which cast doubt on some of his own work. But others did. It became a small classic, and Wittgenstein returned to Cambridge a legendary figure. He looked askance at Russell, now a socialist, atheist and advocate of free love, writing popular books for a living. Russell's role as mentor was over