Intelligent Machinery, A Heretical Theory (c.1951)

Turing gave the presentation ‘Intelligent Machinery, A Heretical Theory’ on a radio discussion programme called The ’51 Society. Named after the year in which the programme first went to air, The ’51 Society was produced by the BBC Home Service at their Manchester studio and ran for several years. A presentation by the week’s guest would be followed by a panel discussion. Regulars on the panel included Max Newman, Professor of Mathematics at Manchester, the philosopher Michael Polanyi, then Professor of Social Studies at Manchester, and the mathematician Peter Hilton, a younger member of Newman’s department at Manchester who had worked with Turing and Newman at Bletchley Park. Turing’s target in ‘Intelligent Machinery, A Heretical Theory’ is the claim that ‘You cannot make a machine to think for you’ (p. 472). A common theme in his writing is that if a machine is to be intelligent, then it will need to ‘learn by experience’ (probably with some pre-selection, by an external educator, of the experiences to which the machine will be subjected). The present article continues the discussion of machine learning begun in Chapters 10 and 11. Turing remarks that the ‘human analogy alone’ suggests that a process of education ‘would in practice be an essential to the production of a reasonably intelligent machine within a reasonably short space of time’ (p. 473). He emphasizes the point, also made in Chapter 11, that one might ‘start from a comparatively simple machine, and, by subjecting it to a suitable range of ‘‘experience’’ transform it into one which was more elaborate, and was able to deal with a far greater range of contingencies’ (p. 473). Turing goes on to give some indication of how learning might be accomplished, introducing the idea of a machine’s building up what he calls ‘indexes of experiences’ (p. 474). (This idea is not mentioned elsewhere in his writings.) An example of an index of experiences is a list (ordered in some way) of situations in which the machine has found itself, coupled with the action that was taken, and the outcome, good or bad. The situations are described in terms of features.