(The following editorial first appeared in the November 1988 editorial issue of Analog Science Fiction and Fact. Thirty-five others, on a wide range of topics, are collected in the 2002 Tor book Which Way to the Future? A different one (usually one not available in the book) will be posted here a few times a year. And, of course, brand-new ones appear in each issue of Analog.)

Throg crouched in the bushes at the edge of the clearing and scratched his neck in puzzlement. He had never before seen anything like the object standing there—something rather like a cave, but standing out in the open instead of set into a cliff. It was smoother, shinier, and more regular in shape than anything else he had seen in all his wanderings in these mountains. The four beings who had emerged from it looked something like men (or women?), but they, too, were oddly smooth and shiny and colorful, and much too tall. They made gestures and noises that sounded vaguely like talking, but none of it made any sense. Two of them stayed in the clearing while the other two disappeared into the forest. Throg felt a burning desire to watch all four of them, but he had to choose. He stayed where he was.

The two mysterious beings who remained carried unrecognizable objects in their hands, pointing them here and there in a way that reminded Throg of some of his Shaman’s rituals. Throg watched and watched, hoping to make some sense of what he was seeing, but understanding never came. Finally, when the sun had set behind the trees and Throg began to crave the security of his cave and his family, the two wandering strangers returned to the clearing. They traded a few raucous sounds and gestures with the other two, then all four somehow made an opening in the wall of the shiny cave-that-wasn't, and disappeared inside.

And then the entire thing disappeared, instantly, with a sound like a thunderclap, leaving no trace of itself but some flattened grass where it had been and the sighing and fluttering of leaves in the air that it had somehow disturbed. Throg, now terrified, ran back to his cave as fast as he could in the dying light, and crouched by the fire, holding his woman and rocking until sleep came to them both.

The next morning he returned to the clearing, emboldened by the light of day to seek any clues that the strange beings might have left behind. He found one and only one, but he found it more puzzling than enlightening. His intuition said it was a tool of some sort, but he couldn't imagine a job that it would be good for. The workmanship he could recognize and envy: he would have loved to have a dagger or a spear so hard and smooth and with a point so sharp. But what good was a sharp point when the blade was twisted into a spiral coil that would resist all efforts to push it into anything? The thing would be useless! Frustrated and disgusted, Throg tossed it into the bushes and went hunting—with a new appreciation for the qualities of his own blades.

Throg never did figure it out, poor fellow, but he can hardly be blamed. Actually, a corkscrew makes very little sense unless you have the concepts of a bottle stoppered by a cork, and the mechanical advantages obtainable from helical devices and motions. We can recognize the function of most "primitive" artifacts (or can we?) because we have at least a general, second-hand memory of the functions they were used for—and those functions are generally simple, basic ones like cutting or stabbing. We would have relatively little trouble recognizing Throg's dagger and spear, but it would be asking too much for Throg to recognize something which is only useful if you have a bottle of, say, Chateauneuf du Pape.

And a corkscrew is probably the least puzzling thing Throg's time travelers brought with them. A great many modern tools would be incomprehensible to someone from an earlier era, not just because their functions did not yet exist, but because their functions exist only in terms of interaction with other tools. A spear or dagger does something clearly useful all by itself: with no accessories required, it kills food or cuts it into manageable portions. A corkscrew is also a food-getting tool, but it only works in a context where other tools called bottles and corks exist to carry and protect liquids, and still other tools exist to make bottles and stoppers. The relationship between a corkscrew and the other tools which must be used in conjunction with it is relatively simple; some others are a lot more complicated and therefore even harder to explain to Throg. And such relationships are not a few scattered anomalies. In a culture as deeply into technology as ours, they are the rule rather than the exception. I can see a wide range of examples, from simple to complex, without leaving my chair.

Some, like the corkscrew, are relatively simple—but still way beyond Throg's experience. A Phillips head screwdriver might look to Throg like another botched attempt at a dagger: great material, but a dull point with a peculiar shape whose fashioning obviously wasted a lot of skill and effort that might have gone into making something simpler but more effective. Without the concept of the screw as a simple machine and a fastener, he could have no inkling of its true function. If one of us learned the other's language, and laboriously got across the concept of the corkscrew, we might then show him an electric can opener and explain that it, like the corkscrew, is a tool for opening food and drink containers. But before the claim could even begin to make sense, we'd have to explain enough metallurgy to make a tin can sound believable. Even then, he couldn't believe we were babbling about anything more than systematized delusions unless we brought along something to plug it into for a demonstration.

An ironing board might make sense, as an awkwardly designed table—but Throg would be unlikely to guess its real purpose unless he'd seen ironable fabrics, and a hot object used to dewrinkle them. Still, that would be a lot easier to explain than an oil filter wrench, whose sole reason for existence is to change an esoteric part of a vehicle whose very existence would seem to Throg the wildest sort of fantasy. Or how about my radio alignment tool, a small plastic rod that looks like a flat-blade screwdriver on one end and an Allen wrench on the other, used for fine-tuning coils in radio receivers without introducing any magnetic interference during the process? A simple thing, but Throg's best guess might be that it was an even lousier dagger than the corkscrew or the Phillips head screwdriver, being made out of much flimsier material and having nothing even remotely resembling a decent point. Let's see you try to tell him what it's really good for, without sounding like you're raving about "magic."

My trumpet mutes might be interpreted as water jugs of relatively impractical design. The fact that their real purpose is to produce subtle changes in the tone quality of a musical instrument would not be obvious unless the instrument itself was produced and demonstrated. That one we might be able to manage, at least approximately; Throg may well have learned to blow an animal horn with its tip broken off. A clarinet ligature might be a little harder to explain, but it, too, would probably not be too hard to get across.

But how about a bicycle pump? The remote control for a VCR? The surge protector attached to the computer I'm writing this on? Or a parking meter? To make any sense at all, that one has to be related not only to other mechanical devices, but to social inventions that are still way off in Throg's future, like land ownership, money, and centralized government.

All of these examples have one important property in common: they are all single parts of systems of tools and can serve their intended functions only when used in conjunction with the other parts of the system. The system may be thought of as a chain, with no two links alike. The finder from a different culture, trying to guess the function of one tool of the system, must somehow try to reconstruct the whole chain from a single (and not necessarily typical) link.

At this point, to keep things in perspective, we would do well to remind ourselves that Throg was not an intrinsically stupid, dull, or otherwise inferior fellow. He merely lacked several thousand years of vicarious experience that we have. We can expect to find ourselves in a very similar position if we ever find ourselves confronted with artifacts from alien (or time-machined) cultures with lots of cultural background that we don't share.

And please note carefully that "artifacts" do not have to be tooled chunks of metal or plastic. They can be institutions, as in the parking meter example above—or messages.

There has been a great deal of discussion, during the last few years, of the "Fermi paradox": the observation that technological cultures should be common in the universe at large, interstellar communication and even travel should be a lot easier than we used to think, and yet we haven't met or heard from any aliens. So where are they? Well, the assumption that we've never seen a message implies the assumption that we'd recognize one if we saw it. I'm not so sure we would. It's true that a lot of effort has gone into imagining forms that messages might take, but these have tended to follow the lines of, "What might we send if we wanted to be recognized and understood by another technological civilization that we've never met?" The reasoning in many of these is such that I think it is reasonable to hope that someone Out There, finding a message we've designed along the lines proposed, would be able to decipher it. It's even reasonable to hope, though I think a shade less convincing, that somebody trying to contact us might follow sufficiently similar lines of reasoning to come up with something we could recognize.

But what if another civilization is not trying to contact us, but simply going about its own business in its own way, neither knowing nor caring whether we're here or not? The routine internal messages of a going interstellar civilization do not seem likely to take the forms proposed for "beginner's lessons," but rather to use the most convenient and cost-effective methods that civilization has been able to develop for itself. The tools they use, like the tools we use, may make sense only in the context of the other tools they've been designed to be used in conjunction with.

Consider a close-to-home example. I mentioned earlier that I'm writing this on a computer. After I deliver a copy of it to the typesetter, I'll keep it filed as a microscopic pattern of magnetic ordering on an apparently featureless disk encased in a 3.5" plastic square, along with a bunch of similarly invisible patterns representing various other documents. Our old friend Throg would probably see nothing of value in it at all. Even my own great-grandparents would have recognized the few lines of not very informative English written on the diskette's label, but I don't think it likely that they would have suspected that the disk itself contained information equivalent to a respectable-sized book. That information can be read only by a suitably equipped computer—and even if the disk is the type that a particular computer likes to use, that computer may not be able to read it if it's formatted for a different type of system.

Given information stored in that compact a form, encoded in a way that is only accessible via a complex and highly specialized technological context, I can't help wondering: how likely is it that Johann Gutenberg or Leonardo da Vinci or Isaac Newton would suspect that a floppy disk or hard disk contained any information at all, much less what kind and how much?

And when I think of how rapidly the technology that uses computers and disks has evolved (and continues to evolve), I must seriously wonder how likely we would be to recognize the information packets used by aliens—or even our own descendants a mere century hence.