It is one of the chief skills of the philosopher not to occupy himself with questions which do not concern him.

Russell had agreed to write an introduction to explain why it was important because it was otherwise unlikely to have been publiLudwig Wittgensteind: it was difficult if not impossible to understand and Wittgenstein was unknown in philosophy. He wrote: "I was shown into Frege's study.

He was professor in philosophy at the University of Cambridge from 1939 until 1947. He described philosophy however as "the only work that gives me real satisfaction. In the words of his friend and colleague Georg Henrik von Wright: "He was of the opinion.