There’s a saying – or maybe a truism – that the test of any new technology lies in its ability to reproduce pornography. Long ago, pornography was the stuff of private collections: crude figurines and drawings that spread their influence only as far as they could be carried. But man could not live in this wilderness forever. He had opposable thumbs and pressing needs, and thus were born woodblock printing, engraving, movable type, daguerreotype, halftone printing, photography, the moving image. Man needed these innovations, of course, to spread the great truths of God, nature, king and country. But it was never very long before some guy wandered into the workroom of the newest inventor, took a look at his gizmo and thought, You know what I could use that for?

Down through the ages, one thing united these mass-produced forms of pornography: the understanding that, no matter how exciting, they were always and only a pale imitation of the real thing. Any travelling salesman who checked into a motel with his copy of Playboy would rather have had a human being on his arm.

Atlantic