With one rub of his lamp, Aladdin could command an intelligent being able to fulfil all desires. His genie was a spirit. But the dream of powerful and intelligent artificial servants has also encompassed physical beings. Now, it is becoming a reality built of silicon, metal and plastic. But is it a dream or a nightmare? Will clever machines prove beneficial? Or will they be Frankenstein monsters?

This is the question raised by The Second Machine Age, a new book by Erik Brynjolfsson and Andrew McAfee of the Massachusetts Institute of Technology. This predicts that we will experience “two of the most amazing events in human history: the creation of true machine intelligence and the connection of all humans via a common digital network, transforming the planet’s economics. Innovators, entrepreneurs, scientists, tinkerers, and many other types of geeks will take advantage of this cornucopia to build technologies that astonish us, delight us, and work for us.”

What distinguishes the second machine age from the first is intelligence. The machines of the first age replaced and multiplied the physical labour of humans and animals. The machines of the second age will replace and multiply our intelligence. The driving force behind this revolution is, argue the authors, the exponential increase in the power (or exponential fall in the cost) of computing. The celebrated example is Moore’s Law, named after Gordon Moore, a founder of Intel. For half a century, the number of transistors on a semiconductor chip has doubled at least every two years. Similar progress has occurred elsewhere. (See chart.)