A way to talk about what we don't need to know, what we don't want to know, and what we should understand better.
He was trying to make sense of the processes by which oil comes out of the ground and ends up ultimately fueling someone's car or a power plant. But in a country whose main asset nowadays (never mind its earlier role as cradle of civilization) is oil, he found this remarkably difficult to do. "[I]n all my time in Iraq I would see the oil itself only once," he wrote.
He continued, "I had come to think of Iraq as a kind of black box. Not the black box engineers analyze after a plane crash ... but rather the black box engineers speak of in describing a mechanism with a known function and an unknown method. The pig goes in one end, the sausage comes out the other, and what goes on in between is no one's business. More and more of what happens in the world happens inside black boxes."
In the automobile, for instance, Mr. Mitchell explains that not so long ago anyone who cared to look could pop the hood on his or her car to get a sense of its workings. "...[Y]es, gas flowed in through this line, and these ceramic plugs probably sparked that gas, and these tiny explosions – you could practically hear the individual pistons! – were probably spinning that shaft. Now, of course, the inside of an engine compartment is almost entirely sealed off."
And it seems to take a computer to diagnose almost anything wrong with a car unless it just needs a fill-up.
"Black box" is a phrase accommodating several different meanings at once, as an office building may house several different businesses that share nothing but an address.
The black boxes of aviation, for instance, which Mitchell alluded to, contain voice and data recordings that help safety investigators determine the causes of airline crashes. By the way, these aren't actually black.