One of the more overblown comments to pass the lips of Donald Trump has beenis the claim that he would make the US safe once he became president. “The crime and violence that today afflicts our nation will soon come to an end,” he told the Republican National Convention last month. “Beginning on January 20 2017, safety will be restored.”

Mr Trump’s claim would appear to fly in the face of several millennia of human experience and was duly dismissed by some commentators as nothing more than fiction. In the adage of our age, this was yet another example of volume trumping truth. Say something loudly enough and boldly enough, and it assumes its own reality.

But just as the world of politics seems to be sliding from nonfiction into fiction, so the world of technology seems to be heading the other way. Ideas once regarded as inhabiting the wilder reaches of our imaginations are fast becoming reality.