It is in the context of the Great Recession that people started noticing that while machines have yet to exceed humans in intelligence, they are getting intelligent enough to have a major impact on the job market. In their 2011 book, Race Against The Machine: How the Digital Revolution is Accelerating Innovation, Driving Productivity, and Irreversibly Transforming Employment and the Economy authors Erik Brynjolfsson and Andrew McAfee, argued that "technological progress is accelerating innovation even as it leaves many types of workers behind." Indeed, over the past 30 years, as we saw the personal computer morph into tablets, smartphones, and cloud computing, we also saw income inequality grow worldwide. While the loss of millions of jobs over the past few years has been attributed to the Great Recession, whose end is not yet in sight, it now seems that technology-driven productivity growth is at least a major factor. Such concerns have gone mainstream in the past year, with articles in newspapers and magazines carrying titles such as "More Jobs Predicted for Machines, Not People," "Marathon Machine: Unskilled Workers Are Struggling to Keep Up With Technological Change," "It's a Man vs. Machine Recovery," and "The Robots Are Winning."

Early AI pioneers were brimming with optimism about the possibilities of machine intelligence. Alan Turing's 1950 paper, "Computing Machinery and Intelligence" is perhaps best known for his proposal of an "Imitation Game", known today as "the Turing Test", as an operational definition for machine intelligence. But the main focus of the 1950 paper is actually not the Imitation Game but the possibility of machine intelligence. Turing carefully analyzed and rebutted arguments against machine intelligence. He also stated his belief that we will see machine intelligence by the end of the 20th century, writing "I believe that at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted."

While we now know that Turing was too optimistic on the timeline, AI's inexorable progress over the past 50 years suggests that Herbert Simon was right when he wrote in 1956 "machines will be capable ... of doing any work a man can do." I do not expect this to happen in the very near future, but I do believe that by 2045 machines will be able to do if not any work that humans can do, then a very significant fraction of the work that humans can do. Bill Joy's question deserves therefore not to be ignored: Does the future need us? By this I mean to ask, if machines are capable of doing almost any work humans can do, what will humans do? I have been getting various answers to this question, but I find none satisfying.

A typical answer to my raising this question is to tell me that I am a Luddite. (Luddism is defined as distrust or fear of the inevitable changes brought about by new technology.) This is an ad hominem attack that does not deserve a serious answer.

We are facing the prospect of being completely out-competed by our own creations.

A more thoughtful answer is that technology has been destroying jobs since the start of the Industrial Revolution, yet new jobs are continually created. The AI Revolution, however, is different than the Industrial Revolution. In the 19th century machines competed with human brawn. Now machines are competing with human brain. Robots combine brain and brawn. We are facing the prospect of being completely out-competed by our own creations. Another typical answer is that if machines will do all of our work, then we will be free to pursue leisure activities. The economist John Maynard Keynes addressed this issue already in 1930, when he wrote, "The increase of technical efficiency has been taking place faster than we can deal with the problem of labour absorption." Keynes imagined 2030 as a time in which most people worked only 15 hours a week, and would occupy themselves mostly with leisure activities.