Stanislaw Ulam writes that John von Neumann once explained the coming singularity by saying, 

"The ever accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue."

J. C. Oxtoby, B. J. Pettis, G. B. Price, John von Neumann, 1903-1957, 
American Mathematical Soc., Dec 31, 1966.