日期:2017-01-07 08:01


Kenneth Harrison was also acquainted with some of Russell’s ideas, and he and Alan would spend hours discussing them.
Rather to Alan’s annoyance, however, he would ask ‘but what use is it?’ Alan would say quite happily that of course it was completely useless.
But he must also have talked to more enthusiastic listeners, for in the autumn of 1933 he was invited to read a paper to the Moral Science Club.
This was a rare honour for any undergraduate, especially one from outside the faculty of Moral Sciences, as philosophy and its allied disciplines were called at Cambridge.
It would have been a quite unnerving experience, speaking in front of professional philosophers, but he wrote with customary sangfroid to his mother:
… I am reading a paper to the Moral Science Club on Friday. Something by way of being Mathematical Philosophy. I hope they don’t know it all allready.
The minutes24 of the Moral Science Club recorded that on Friday 1 December 1933:
The sixth meeting of the Michaelmas term was held in Mr Turing’s rooms in King’s College.
A.M. Turing read a paper on ‘Mathematics and logic’.
He suggested that a purely logistic view of mathematics was inadequate; and that mathematical propositions possessed a variety of interpretations, of which the logistic was merely one. A discussion followed.
R.B. Braithwaite (signed).
Richard Braithwaite, the philosopher of science, was a young Fellow of King’s; and it might well have been through him that the invitation was made.
Certainly, by the end of 1933, Alan Turing had his teeth into two parallel problems of great depth. Both in quantum physics and in pure mathematics, the task was to relate the abstract and the physical, the symbolic and the real.
German mathematicians had been at the centre of this enquiry, as in all mathematics and science.
But as 1933 closed, that centre was a gaping, jagged hole, with Hilbert’s Gttingen ruined.
John von Neumann had left for America, never to return, and others had arrived in Cambridge.
‘There are several distinguished German Jews coming to Cambridge this year,’ wrote Alan on 16 October. Two at least to the mathematical faculty, viz. Born and Courant.’
He might well have attended the lectures on quantum mechanics that Born gave that term, or those of Courant on differential equations the next term.
Born went on to Edinburgh, and Schrdinger to Oxford, but most exiled scientists found America more accommodating than Britain.
The Institute for Advanced Study, at Princeton University, grew particularly quickly.
When Einstein took up residence there in 1933, the physicist Langevin commented, ‘It is as important an event as would be the transfer of the Vatican from Rome to the New World.
The Pope of physics has moved and the United States will become the centre of the natural sciences.’
It was not Jewish ancestry alone that attracted the interference of Nazi officialdom, but scientific ideas themselves, even in the philosophy of mathematics:
A number of mathematicians met recently at Berlin University to consider the place of their science in the Third Reich.
It was stated that German mathematics would remain those of the ‘Faustian man’, that logic alone was no sufficient basis for them, and that the Germanic intuition which had produced the concepts of infinity was superior to the logical equipment which the French and Italians had brought to bear on the subject.
Mathematics was a heroic science which reduced chaos to order.
National Socialism had the same task and demanded the same qualities.
So the ‘spiritual connexion’ between them and the New Order was established—by a mixture of logic and intuition
To English minds, the wonder was that any state or party could interest itself in abstract ideas.