Turing and the paranormal

Of the nine arguments against the validity of the imitation game that Alan Turing anticipated and refuted in advance in his ‘Computing machinery and intelligence’, the most peculiar is probably the last, ‘The argument from extra-sensory perception’. So out of step is this argument with the rest of the paper that most writers on Turing (myself included) have tended to ignore it or gloss over it, while some editions omit it altogether.1 An investigation into the research into parapsychology that had been done in the years leading up to Turing’s breakthrough paper, however, provides some context for the argument’s inclusion, as well as some surprising insights into Turing’s mind. Argument 9 (of the nine arguments against the validity of the imitation game) begins with a statement that to many of us today will seem remarkable. Turing writes:… I assume that the reader is familiar with the idea of extra-sensory perception and the meaning of the four items of it, viz. telepathy, clairvoyance, precognition, and psycho-kinesis. These disturbing phenomena seem to deny all our usual scientific ideas. How we should like to discredit them! Unfortunately the statistical evidence, at least for telepathy, is overwhelming…. To what ‘statistical evidence’ is Turing referring? In all likelihood it is the results of some experiments carried out in the early 1940s by S. G. Soal (1899–1975), a lecturer in mathematics at Queen Mary College, University of London, and a member of the London-based Society for Psychical Research (SPR). To give some background, the SPR had been founded in 1882 by Henry Sidgwick, Edmund Gurney, and F. W. H. Myers—all graduates of Trinity College, Cambridge—for the express purpose of investigating ‘that large body of debatable phenomena designated by such terms as mesmeric, psychical and spiritualistic . . . in the same spirit of exact and unimpassioned enquiry which has enabled science to solve so many problems, once no less obscure nor less hotly debated’. Although the membership of the SPR included numerous academics and scientists—most notably William James, Sir William Crookes, and Lord Rayleigh, a Nobel laureate in physics—it had no academic affiliation. Indeed, in the view of their detractors, the ‘psychists’, as they were known, occupied the same fringe as the mediums and mind-readers whose claims it sought to verify—or disclaim.