Intelligent machines are already replacing low-skilled workers. Soon they'll replace high-skilled ones too.

We are still a long way from all-round human intelligence—smart machines are becoming more flexible but still tend to excel in only a specific area—but Mr. Ford lucidly sets out myriad examples of how focused applications of versatile machines (coupled with human helpers where necessary) could displace or de-skill many jobs. If you are of the professional classes, you will likely read with mounting dismay Mr. Ford’s compelling explanation of how tools that encapsulate “analytic intelligence and institutional knowledge” will enable less qualified rivals to carry out your job proficiently, quite possibly from another country. An intelligent system might mine huge corporate data sets to distill years of experience into simple instructions for an overseas worker—who can then use translation and telepresence to overcome linguistic and geographical barriers. When the tools systems have become smart enough, those offshore workers may in turn be deemed surplus: In a particularly dastardly move, computers may even acquire those smarts by spying on their human users.

The author is persuasive in his discussion of the business logic that makes this process seem all but inevitable. Machines may be less accomplished than humans, but they are often cheaper, more dependable and more docile. While you might worry about their growing abilities, it is the economic incentives that seem truly problematic. Mr. Ford worries that if this trend runs away it will prove bad for all but the ultra-wealthy capitalists who own the machines. Because workers are consumers too, a declining workforce translates into declining demand, and that threatens the entire edifice of modern capitalism. Continue as we are, he suggests, and we may return to feudalism.