The Past Was More Than You Think

Living in a world of mystery

I love strange times and faraway places. Growing up, my only foothold into these realms of mystery were Choose Your Own Adventure books, Dr. Who (you know, back when Dr. Who was rad), and a dreadful roleplaying game which, if you’re lucky, you never heard of.

Sadly, time passed. I outgrew 90% of the CYOA books, Dr. Who eventually segued into irrelevance and farce, and my tolerance for bad roleplaying games came to an end. But I’ve never lost that fascination for strange and distant worlds, and whenever I run into people who act and speak as though the Newest Thing is the best thing, it rankles.

Don’t get me wrong. Living in the 21st century, only a fool would dismiss the pace of technological advancement. And ultimately the trendy Twitterati who obsess over the wonders of the present have it about 70% right—we really do live in an age of wonders. Is this not the first time in human history that we’ve ever had virtual reality, the first time the human genome has been sequenced, the first we have ever seen of artificial general intelligence? It’s not at all unreasonable to be dazzled by the amazing inventions of the present—and to fear possible developments that loom on the horizon.

But 70% is not 100%. And I do wonder whether anyone has ever pointed out to you that this widespread focus on the new and current, and the attendant dismissal of the past, is myopic and narrow-minded. Consider if you will an innovation of the previous century which revolutionized warfare: the tank.

Armored vehicles, fast food, and cellular communication: Life in The Age of Wonders

Fun With Tanks

Readers with a background in statistics may be familiar with the German Tank Problem:

During the course of the Second World War, the Western Allies made sustained efforts to determine the extent of German production… Shortly before D-Day, rumors indicated that large numbers of Panzer V tanks were being used.

To determine whether this was true, the Allies attempted to estimate the number of tanks being produced. To do this, they used the serial numbers on captured or destroyed tanks… Analysis of wheels from two tanks (32 road wheels each, 64 road wheels total) yielded an estimate of 270 tanks produced in February 1944, substantially more than had previously been suspected.

German records after the war showed production for the month of February 1944 was 276.

It can be established that an unbiased estimator for the total number of enemy tanks is:

\(N = m\left(1 + \frac{1}{k} \right) - 1\)

Where N is the estimated number of tanks, m is the largest serial number from all k of the tanks you’ve discovered. The standard deviation is something like N/k, which gives a clue about how accurate the estimation is.

A bit of playing around with the expression will show that if the highest serial number you’ve seen is 99, and you’ve already encountered 50 tanks, you can say with confidence that there are probably only about 100. But if the only serial number you’ve encountered is 99, then the total number of tanks may be closer to 200, and it’s much harder to rely on this estimate.

Stated in words, what this tells us is that:

• The more information we have, the more confident we can be about the world we live in tanks.

• The less information we have, the easier it is to be wrong about tanks.

A critical assumption of this model is that all tanks are equally likely to be encountered, regardless of their serial number. If the enemy has been deliberately pushing its earliest tanks into the front lines and withholding or safeguarding its later tanks, then those tanks we would capture would tend to give us a false underestimate of enemy capabilities. So the above should really be amended to:

• The more unbiased information we have, the more confident we can be.

• The less unbiased information we have, the less confident we can be.

How to know, or guess, whether our information is biased or not? If we can get some idea of how our information is biased, and in one direction, we can correct for that—at least somewhat. Our estimator can never be biased upwards (it only depends on the highest serial number found). It can only be biased downwards from the true value. Knowing this then gives us the ability to manually correct our estimator, and the uncertainty we attribute to the estimate, upwards. How far we correct it depends on how badly we think bias may be affecting our data, and that’s a ticklish question. But we never need to correct our estimate down, and believe there is less there than our estimator tells us. We only need to wonder whether there might be more.

The tl;dr here is that possible bias doesn’t have to be fatal to understanding, so long as we can identify which direction that bias is in. This may be critical if you find yourself in a protracted world war, but also in other situations. Clever readers who recall the title of this post might be thinking about those other situations already, since this is not really a post about tanks. (No it’s not a post about apples either)

Thinking About the Past

What I am interested in is time. My university training is in physics, and this is what physicists do: we think about the past, and the future, to try to understand how systems evolved to reach the present, and where they will go. For instance, consider this scenario:

Let us imagine that it is a hundred years ago—the early years of the 20th century. An archaeologist claims to have found numerous human remains, including stone spear-points, in a dig site in New Mexico. The remains are dated to approximately 11 thousand years before the present, or 11kya. Never before have remains dating this far back been found in the New World. Thrilled by their discovery, the archeological community shares this result with the world, arguing that this represents evidence for the first humans arriving in the Americas across the Bering Straight land bridge, which lay above sea level as late as 18kya.

This is, roughly speaking, what actually happened in the previous century. The archeologist was Edgar Howard, and the dig site was in Clovis, New Mexico; the countryside in the area is below at left from a screen capture found on Google Maps at this link. Below to the right is a spear point attributed to the Clovis Culture.

Since the original find, many more remains were identified in the area. The discovery lit up the archaeological community, and captured the national attention. For decades, it was assumed that these were remains from the very first humans in the Americas. That is the story I learned in school.

But then, in 2004:

Radiocarbon tests of carbonized plant remains where artifacts were unearthed last May along the Savannah River in Allendale County by University of South Carolina archaeologist Dr. Albert Goodyear indicate that the sediments containing these artifacts are at least 50,000 years old, meaning that humans inhabited North American long before the last ice age.

The findings are significant because they suggest that humans inhabited North America well before the last ice age more than 20,000 years ago, a potentially explosive revelation in American archaeology.

Goodyear, who has garnered international attention for his discoveries of tools that pre-date what is believed to be humans' arrival in North America, announced the test results, which were done by the University of California at Irvine Laboratory, Wednesday (Nov .17).

"The dates could actually be older," Goodyear says. "Fifty-thousand should be a minimum age since there may be little detectable activity left."

This last statement is the crux of the matter. Archaeologists found evidence placing the habitation of the Americas at around 11kya, and reasoned that it pointed to human habitation of the area somewhere around 20kya. But then, further evidence arose which showed the latest date must actually be 50kya.

This still does not mean humans arrived in the Americas 50,000 years ago. It means they arrived here at least by then. Possibly before.

Of course, this isn’t the same situation as with the German Tank Problem. We can’t look at this as though we found remains with a “serial number” of 11,000, and then another with “serial number” 50,000. Instead, archaeologists had been excavating numerous recent remains; they had so many finds that it seemed reasonable to presume that this gave us a fairly complete picture. Again, a critical assumption of the statistical model we looked at in the previous section was that that all tanks were equally likely to be encountered, regardless of their serial number. But in archeology, we are less likely to discover anything as its age increases—older remains have had more time to decay, and will be buried in deeper strata.

When our thinking is informed by this understanding, we begin to realize that the past is a far richer time than most people like to acknowledge.

What Might Have Lain Undiscovered

We’ve just considered a story that actually unfurled in the field of archaeology. A discovery was made pointing to the earliest peopling of the Americas, and then a new discovery showed that mankind has been walking the soil of the New World for thousands of years earlier.

But what if, instead of this, we imagine that a well known discovery was never made?

Consider the Antikytheria Device: a hand-cranked model of the solar system called an orrery, dated to at least as far back as the first century BC. Originally pulled up from a wrecked Roman cargo ship in early 1900, it was held in the National Museum of Archaeology in Athens without being properly stored. That such a device could be treated so carelessly is disappointing, but the assumption at the time was that it was of no special interest. Looking at the mechanism, it’s easy to see why.

But in 1902, an archaeologist by the name of Valerios Stais examined the device, and found that one of the pieces of rock had a gear wheel embedded in it. He recognized it for what it was—but no one believed him, since it was known that no one in the Classical Era was capable of constructing a clockwork orrery. This remained the assumption of the archaeological community for another fifty years before a British historian named Derek Price became interested in the device; it took another twenty years after that for X-ray images to reveal the internal details of the device in 1971.

For centuries at least, no one believed anyone in the ancient world was capable of making such a thing, because no evidence had been found. The belief was strong enough that, even for generations after the Antikytheria Device was found, it was still assumed to be meaningless. Everyone knew the people of the ancient world couldn’t construct such a thing; ergo, it hadn’t been constructed.

So it should not be hard to consider the next scenario:

Let us imagine that you are reading this post right now, but no Antikytheria Device has been discovered. Do you think the Greeks or Romans living before the time of Christ were capable of constructing an orrery capable of tracking the position of the planets, the moon, and eclipses, with an overall level of sophistication comparable to a 14th century astronomical clock?

Well, what would you have thought? I know exactly what I would have thought: I would have thought No, the ancient Romans couldn’t have done that, since I have no evidence that they could.

Moreover, if the ancients really could have done that, why wouldn’t there have been further progress in the intervening 14 centuries? Fine, maybe some of the technology could have been lost during the Dark Ages, but why make that assumption?

In fact, there’s a very good reason not to default to thinking technology was definitely lost between then and now: If we do make that assumption any time someone asks what the ancients knew, then we have to presume they were also shooting guns and flying to the moon, simply because we’re able to do that today. This isn’t a good bet. (If they had guns, why bother with the scutum and gladius?) The Romans almost certainly couldn’t do everything we can do, so, when asked about any one single thing they might have been able to accomplish, we’d better not assume they couldn’t do it.

I would, however, most definitely have hedged about this. Because I do know that the absence of evidence is not the same as evidence of absence.

Nevertheless, if not for the chance finding of the Antikytheria Device a hundred years ago, we would rightly assume that the ancients had never made such a thing. The fact that we have discovered this fascinating device—a hand-cranked Swiss watch made before Switzerland existed—means we know their skills as artificers must have been at least as good as those of the High Middle Ages.

And I wonder, what else did they know? And, could it even be possible that they knew things we forgot—ancient secrets lost to the relentless flow of time?

Thinking About the Future

But enough of the past. Let’s turn instead to the future:

Imagine that, in the next few years, bioterrorists release a deadly virus at O’Hare International Airport. 99.999% of the human species is wiped out in months, but predictably, a few people hang on along the coasts of Greenland. Forced into a desperate struggle without the industrial foundation necessary to maintain a technological civilization, they soon revert to a Neolithic level of technology, subsisting on the native wildlife.

Time passes. Over the next 20,000 years humanity evolves into the Hyperboreans, a nearly hairless, cold-resistent species adapted to swimming in the waters of the frigid shore. Tentatively at first, they spread to the nearby regions to the west, but eventually they develop greenhouses which allow the population to skyrocket.

With their increased numbers, they soon learn to travel across the eastern seas, and colonize the empty northern regions of what is today Northern Europe and Siberia. At first, these virgin territories show no sign of habitation—buildings have long since collapsed, and the remains have rusted away. Even the computers and cell phones have vanished due to plastic-eating bacteria, but…

Eventually an ancient mine is discovered. Strange menhirs are found in distant islands. Fossilized remains are found. Finally the evidence is incontrovertible: humans once covered the entire globe.

Around this time, the Hyperboreans have discovered electricity. They begin building computers, culminating in three enormous supercomputers which they call Angels. Knowing that they themselves possess a natural tendency towards superstition, the Hyperboreans hail the Angels as harbingers of a Golden Age of Rationality. One of the first questions put to the Angels is this: “When were computers first invented?”

And so this is the question I would like to ask you:

How would the Angel reply?