Wittgenstein now got the idea of temporarily exiling himself to Norway for work, and to escape the effects his anxiety had on his contacts with others. According to the biographer, it is possible that Weininger's idea that love is strongest with a certain distance may have influenced his thinking on this point.
Russell reacted with horror to this idea:
"I said it would be dark, & he said he hated daylight. I said it would be lonely, & he said he prostituted his mind talking to intelligent people. I said he was mad & he said God preserve him from sanity. (God certainly will.)".
Before he left, Wittgenstein attempted to acquaint Russell with his latest work; partly because both suspected that he would not be able to work much longer - Wittgenstein, because he had a morbid conviction that he would soon die; Russell, because he thought Wittgenstein was going insane. Russell found Wittgenstein's oral explanations incomprehensible, but Wittgenstein was unwilling to present him with imperfect written work. At length, Russell succeeded in dragging the "Notes on Logic" from Wittgenstein. This work asserts that the claims of the theory of types cannot be "said", but must be "shown" with reference to the types of symbols that are used; Wittgenstein refers to the apparent truisms that in the symbolic language, "A is the same letter as A", "A is the same type of letter as B", and "A is different from x, y and z".
"Notes on Logic" also asserts what would be Wittgenstein's permanent convictions on the nature and role of philosophy. He claimed that it was
- descriptive, not deductive
- gives no pictures of reality
- cannot confirm or refute scientific investigation
- consists of logic (its basis) and metaphysics
In addition, he states that "epistemology is the philosophy of psychology" and that "distrust of grammar is the first requisite of philosophizing".
In Norway he found a refuge from the demands of bourgeois society; it was a productive period for him. At the same time, he was far from isolated, and he learned a good deal of Norwegian. In England, Russell was trying to make sense of the "Notes on Logic" in preparation for a lecture series. He wrote to Wittgenstein hoping for clarification on certain points. Wittgenstein replied impatiently.Among the points he tried to clarify was why he thought the whole of logic had to be derivable from a single proposition. This conviction rested on the fact that certain propositions could be known to be true or false without considering the truth-value of their constituent parts. These are tautologies ("It is either raining or not raining") and contradictions ("It is both raining and not raining"). Wittgenstein argued that a rule could be stated in a proposition that would allow one to determine whether a proposition was a contradiction, a tautology, or neither. Such a proposition would be the basis for all logic, but it is necessary to assume that all true logical propositions are tautologies. Wittgenstein states that "all the propositions of logic are generalizations of tautologies [and vice versa]. There are no other logical propositions."
Russell viewed this as presenting the problem of how all tautologies can be shown to be such by a single method. He was later to tackle this problem by the truth table method.
At length, Wittgenstein's depression and anxiety returned. It increased when he visited his family during Christmas out of a conflicted sense of duty. An exchange of letters with Russell, in which Wittgenstein held forth on Russell's upcoming lectures with a perfectionism which brought forth a sharp reply from Russell, resulted in a letter from Wittgenstein intended to end their association. Wittgenstein changed his mind when Russell replied, repentant, but henceforth they were to eschew "value judgements" in their association and focus only on objective topics.
According to the biographer, Russell had deluded himself into thinking that it was their similarity which caused the problems. In his letters, Wittgenstein focussed instead on the differences. It is notable, also, that in their work on philosophy it had come to the point where Wittgenstein was reporting to Russell on Wittgenstein's work in bulletins, with little discussion.