“Intelligent Machinery, A Heretical Theory.”
A lecture he given in 1951 by Alan TURNING
Here is the full context of that specific passage:
”If a machine can think, it might think more intelligently than we do, and then where should we be? Even if we could keep the machines in a subservient position, for instance by turning off the power at strategic moments, we should, as a species, feel greatly humbled. . . . This new danger is relevant to the even more remote future because at some stage we should have to expect the machines to take control, in the way that is mentioned in Samuel Butler’s Erewhon.”