Futurologists envision a world a million years from now in which the entire solar system has been turned into computronium and nanobots transform our garbage into foie gras. But in my experience, the repeated sin of futurologists is that they often extrapolate from what is new rather than from what is old. Computers and nanotechnology, impressive though they are, are things of relatively recent origin. As such, they are unlikely to be around for very long.
To find something that will pretty certainly endure into the distant future, we are obliged, paradoxically enough, to go back much farther into the past. And if we could cast a look back several million years, we would see, among other things, laughter and numbers. So we can be pretty confident that laughter and numbers will survive long after most of what we’re familiar with is gone.
The insight that old things tend to last and new things tend to disappear flows from the Copernican principle. This principle says, in essence, “You’re not special.” Before Copernicus, we imagined that we occupied a very special place at the center of the universe. Now we know better: We are on an average planet in an average galaxy in an average cluster. But the Copernican principle applies to time as well as to space. If there is nothing special about our perspective, we are unlikely to be observing any given thing at the very beginning or the very end of its existence. And that rather obvious point can lead to some interesting predictions.
Consider the longevity of the human race. If there is nothing special about the moment at which we observe our species, then it is 95 percent certain that we are seeing Homo sapiens in the middle 95 percent of its existence—not the first fortieth (2½ percent) or the last fortieth (2½ percent). Humans have already been around for about 200,000 years. That means we can, with 95 percent confidence, expect the species to endure for at least another 5,100 years (1/39 x 200,000) but for no more than 7.8 million years (39 x 200,000).
It was Richard Gott III, an astrophysicist at Princeton University, who pioneered this sort of reasoning. In a paper published in Nature on May 27, 1993, “Implications of the Copernican Principle for Our Future Prospects,” Gott noted that the Copernican-based calculation gives H. sapiens an expected total longevity comparable to that of other hominid species (H. erectus lasted 1.6 million years) and of mammal species in general (whose average span is 2 million years). It also gives us a decent shot at being around a million years from now.
What else might be around in the Year Million? Consider something of recent origin, like the Internet. The Internet has existed for about 25 years now (as I learned by going on the Internet and looking at Wikipedia). By Copernican reasoning, this means we can be 95 percent certain that it will continue to be around for another seven-plus months but that it will disappear within 975 years. So in the Year Million, there will almost certainly be nothing recognizable as the Internet. (This is, perhaps, not a terribly surprising conclusion.) Ditto for baseball. Ditto for what we call industrial technology, which, having come into existence a little more than two centuries ago, is likely to be superseded by something strange and new in the next 10,000 years.
Laughter and numbers, on the other hand, are good bets to survive a million years because they are two of the oldest things that are part of our lives today. How do we know this? Because we share both laughter and a sense of number with other species, and therefore with common ancestors that existed millions of years ago.
Take laughter. Chimpanzees laugh. Charles Darwin, in The Expression of the Emotions in Man and Animals, noted that “if a young chimpanzee be tickled—the armpits are particularly sensitive to tickling, as in the case of our children—a more decided chuckling or laughing sound is uttered; though the laughter is sometimes noiseless.” Actually, what primatologists call chimp laughter is more like a breathy pant. It is evoked not only by tickling but also by rough-and-tumble play, games of chasing, and mock attacks—just as with children prior to the emergence of verbal joking at age 5 or 6.
The human and chimpanzee lineages split off from each other between 5 million and 7 million years ago. On the reasonable assumption that chimp and human laughter are homologous rather than independently evolved traits, laughter must be at least 5 million to 7 million years old. (It is probably much older; orangutans also laugh, and their lineage diverged from ours about 14 million years ago.) So, by the Copernican principle, laughter is quite likely to be around in the Year Million.
Now take numbers. Chimps can do elementary arithmetic, and they have even been trained to use symbols like numerals to reason about quantity. But the sense of number is not confined to primates. Animals as diverse as salamanders, pigeons, raccoons, dolphins, and parrots have the ability to perceive and represent numbers. A few years ago, researchers at MIT discovered that macaque monkeys had specialized “number neurons” in the brain region that corresponds to the human number module. Evidently the number sense has an even longer evolutionary history than laughter. So again, by the Copernican principle, we can be quite certain that numbers will be around in the Year Million.
But what will our descendants’ mathematics look like? And what will make them laugh? The first question might seem the easier to answer. Mathematics, after all, is supposed to be the most universal aspect of human civilization, the part we assume would extend even to intelligent life elsewhere in the cosmos. In Carl Sagan’s science fiction novel Contact, aliens in the vicinity of the star Vega beam a series of prime numbers toward Earth. The book’s heroine, who works for SETI (Search for Extraterrestrial Intelligence), realizes with a frisson that the prime-number pulses her radio telescope is picking up must be generated by some form of intelligent life. But if the aliens beamed their jokes at us instead, we probably wouldn’t be able to distinguish them from the background noise. Indeed, sometimes we can barely distinguish the jokes in a Shakespeare play from the background noise. Just as nothing is more timeless than number, nothing is more parochial and ephemeral than humor, the core of laughter—or so we imagine. We are confident that a civilization a million years more advanced than our own would find our concept of number intelligible (and we, theirs), but our jokes would have them scratching their heads in puzzlement.