METAPHORS are not born as such. They begin as concrete descriptions of the world, and are only gradually extended to other domains. Without ever crossing a bright line, they become everyday language, divorced from the original referent. (Take "divorced", in that last sentence.) In many cases, the original meaning is even forgotten. Johnson is as guilty as anyone of using metaphors while being confused about their origins.

The nautical age gave us many such metaphors. How many people know the meaning of “three sheets to the wind” or “the cut of his jib” without looking them up? Sport is similar—it is not uncommon for English-speakers from countries that do not play baseball to “cover their bases” or “hit one out of the park”. But where relevance does not matter to the spread and entrenchment of metaphors, longevity is key. The short-lived space age did not write a new chapter in the book of metaphors. (Though “space age” itself is sometimes used to describe futuristic ideas.)

What of the digital age? It is clearly here to stay. And it uses a lot of metaphors derived from common language: “hosts”, “kernels”, “shells”, “servers” and “clients”. But while many of its concepts—networks, links, distributed collaboration—have become part of the way people think, I can think of only a few specific examples of computing terms passing into regular use outside the technorati. Hacking is one: people now hack their lives and hack elections. Bandwidth (though it actually predates computing) is another term of increasing importance in our digital lifestyles. How many times have you heard someone say they don't have the bandwidth to do something? And sometimes, the more fixed and variable bits of a system are called "hardware" and "software", respectively. But given the ubiquity of computing in our lives, this list (though I'm sure readers can think of a few more) is surprisingly short. Technology's own greatest strength—constant, frenetic innovation—may also be its weakness, at least in the world of metaphors.

Consider “click of a mouse”, as in “now you can buy sprockets from Uzbekistan at the click of a mouse.” It was always an ugly phrase. Now it seems anachronistic. Its cousin, “click of a button”, may be less unappealing but it fares little better. Google’s Ngram viewer (click on the image above to enlarge) shows both phrases declining since 2004. That’s even before the iPhone, though the renewed use of “touchscreen” and the rocketing use of “smartphone” (not metaphors) suggests touch-enabled devices have a lot to do with the drop. “Click of a mouse”, then, is unlikely to graduate to metaphor status. Like the monstrosity "cyberspace", it will probably drop out of use in our lifetimes.

But if daily computing has not led to big changes in the way we talk, it still has its own dead metaphors to deal with. The “save” icon in many programs is an example. It is represented by a floppy disk, something that has been the cause of consternation among design aficionados. The debate has carried on to smartphone operating systems. Critics of Apple accuse it of overdoing skeuomorphism, or using familiar analogue metaphors and textures in digital products (a fascinating discussion is here).

This is not surprising. Ever since the graphical user interface first allowed users to click on icons instead of inputting commands, computing has become a primarily visual medium. That is the second reason technology has not created new ways of speaking. Its metaphors exist, but often not in text.