Cambridge and Harvard
IN October 1910 Russell returned to Trinity as Lecturer in Logic and the Principles of Mathematics (at a stipend of £210 a year). His classes were small but distinguished: one course of lectures on mathematical logic was heard by only three men-- C. D. Broad the philosopher, E. H. Neville the mathematician, and H. T. J. Norton, whose work anticipated J. B. S. Haldane's application of mathematics to the problem of heredity. They made it possible for Russell to claim that 'One hundred per cent of my pupils get Fellowships'.
J. M. Keynes was also teaching at Cambridge at this time. Whitehead left Cambridge the year Russell returned, but G. E. Moore came back as Lecturer the year afterwards. The arrival of Ludwig Wittgenstein completed the group of Cambridge philosophers who were destined to dominate philosophical thinking for many years to come.
Wittgenstein was a rich young Austrian who had gone to Manchester University as a research student in engineering, having become fascinated by the new and adventurous science of aviation. He experimented with kites, then decided it was no use designing an aeroplane without first designing an engine for it, and was then led on to design a propeller. This involved working out the right mathematical formulae; and in doing this he grew so interested in the mathematics that he forgot all about the propeller. He asked if there was anyone who knew anything about the principles of mathematics, and was told about Russell. So Wittgenstein went to Cambridge to attend Russell's lectures, and to study under him.
In later years, C. D. Broad described Wittgenstein as 'a genius with all the prima facie appearances of a charlatan'.