"The first is, it will eliminate a lot of existing types of jobs. Gates said that creates a need for a lot of retraining but notes that until schools have class sizes under 10 and people can retire at a reasonable age and take ample vacation, he isn't worried about a lack of need for human labor."

Almost one hundred years ago Keynes predicted drastic cuts to the average worker's labor time, down to 15 hours or so a week. He expected living standards in developed countries would be between four and eight times higher and this would leave people far more leisure time.

Many countries have experienced massive productivity and standards of living increases in the last 100 years, and hours worked has not significantly declined. What makes anyone believe, 'this time is different'?