The known unknown.
Dear Word Detective: As I write, there is a lot on the news about a plane landing rather short of the runway at Heathrow in London, fortunately without any serious injuries to anyone. Pundits of various kinds are speculating about what the “black box” flight recorders will reveal. On the back of that, people are ruminating about where the phrase “black box” came from, as they are bright orange and have never been black, so far as anyone knows. Explanations so far seem to be a bit short of the target, as was the plane. — David, Ripon, England.
Well, it’s good to hear that no one was seriously hurt. But I’m still not getting on any airplanes. I actually haven’t been on a plane since 1994, and nothing I’ve heard about air travel in the years since then has made me eager to have my shoes searched. If I’m going to be treated like a criminal, I’d like it to be for doing something fun, not for flying to Newark.
If one were to conduct a survey among a large group of people, it’s likely that most of them would associate “black box” with the device you speak of, also (and more properly) known as a “flight recorder.” These devices, found on every large aircraft, monitor and record a wide variety of information about the course of the aircraft’s journey, including the craft’s altitude, speed and heading, as well as the functioning of the hundreds of mechanical and electrical systems that keep the thing aloft. The “black box” only becomes important, of course, if something goes wrong, and the devices are built to withstand the heat and impact of a crash so that the cause of the mishap can, with luck, be identified. But, as you say, the “black boxes” are routinely painted bright orange so they can be more easily found at a crash site. So why “black box”?
The reason is that the “black” in “black box” doesn’t really refer to the color of the device, but to the aura of mystery associated with it. The first known use of the term in print was back in the 17th century, when “black box” was used to mean “coffin” (“She had been in the black Box (meaning the Coffin) e’re now,” 1674). The “black” in that instance referred not to the color of the coffin, but to the “blackness” inside, both the darkness and the mystery of death itself. That aspect of “mystery” is central to “black box.” The first use of the term in regard to aircraft was in the Royal Air Force during World War II, when “black box” became airman’s slang for the mysterious boxes (actually navigational equipment) mounted in their planes. No one in the crew understood how the gizmos did what they did — they just did it without any action on the part of the crew.
The term “black box” has since come to mean any device or process whose purpose or effect is clear to the user, but whose actual means of operation are a mystery. Television sets, for instance, are “black boxes” to most consumers (that “no user-serviceable parts inside” sticker on the back drives home the point). Despite advances in neuropsychology, the human brain remains, in large part, a “black box.” And the US electoral system, quite apart from the question of electronic voting machines, remains a “black box” to many voters (not to mention, every so often, a “Pandora’s box”).