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That’s the question everyone seems to be asking about the extraterrestrials that supposedly flourish throughout the galaxy. Why aren’t they dropping by Earth all the time, like the alien travelers in the Men in Black series? To this I have a counter question: Well, where are we?
Human beings are pretty smart—not exactly worms, as Neil DeGrasse Tyson seems to think, waiting for some smarter species to come along and study us.1 In fact, we’re the smartest creatures on this planet, probably in this solar system, and maybe for a couple of parsecs in any direction around here. So why aren’t we out there, going on a worm hunt?
Consider: On a planet that is now four billion years old, our own Earth, it is only in the last:
• Million years that any animal has possessed both the brainpower and the physical numbers to form any kind of civilization.
• Ten thousand years that human beings have had the technology—herding skills and agriculture—to settle down in river valleys and build that civilization.
• Five thousand years that we’ve had writing systems to carry our words and ideas beyond the next generation.
• Hundred years since we started using radio waves to carry those words and ideas. Every means of communication that came before radio remained dark to anyone above our atmosphere.
• Sixty-odd years since we had rockets to reach above our own atmosphere.
• Forty-odd years since we put a human footprint on another world, our own Moon.
• Year or so that the Voyager probes broke away from the Sun’s immediate environment.
Aside from a few camping trips on the edge of space, we haven’t gone back to the Moon or established any serious physical presence above our atmosphere. We’ve sent a number of robot probes to examine the other planets in our system and explore its environs. But we haven’t gone in person and it may be years before we go out again.
We’re the hot stuff of this solar neighborhood, and yet we aren’t out there looking for worms, or for our equals, or even our superiors.
I believe the universe teems with life. Any planet that can harbor some form of this entropy-reversing energy flux will probably do so. And yet I think most habitable planets probably resemble ours of the past four billion years: quietly cooking up life in all its variations and slowly developing its potential, but still dark to anyone who happens to pass through this solar system and take a brief look or a scan while on their way to some other star that seems more promising.
Life is abundant. But the kind of life that has the brains, the organization, the technology, and not least the time and money to go out among the stars and look for more life—that is probably pretty rare.
And while it may be nice to think that we’re just worms—or an abhorrent species of primitive, violent, dangerous creatures, like a monkey troop afflicted with scabies—and that a greater, wiser, more peaceful, benevolent, and powerful civilization is waiting out there, ready to become humanity’s foster parent, teacher, and guide to a better state of grace … I’m not holding my breath. The human yearning for a parent figure lasts far into adulthood. The notion that we can relax our grip, step back into the crèche of childhood, and let some godlike creatures plan and define our next steps … is a fantasy.
For one thing, there may be a limit to the intelligence of any single creature or even a hive mind. Our brains have on average 100 billion neurons, each with multiple synapses making connection to other neurons. That’s a far more powerful and versatile computer than any engineer has been able to build by cramming transistors on a chip, although computers will probably overtake us meats soon enough. There may be a limit to how much raw computing power our kind of life chemistry can coordinate. I’m not saying there is a limit, just that there may be one.
If you believe that evolution is a reliable principle and that it probably operates on other planets as well as ours, the nature of evolution may define such a limit. Humans are very smart. We are much smarter than the animals we hunt or herd for food, such as deer, cows, and goats, and smarter even than the animals that would hunt us, such as lions and bears. We may be an order of magnitude too smart for the hunter-gatherer existence that we left behind when we settled on the banks of the Indus, the Euphrates, and the Nile rivers. But while that excess intelligence has brought us a long way, the process of building societies, governments, industries, and marketplaces has sopped up much of that excess intelligence and then created new, even more complex challenges.
But evolution suggests that we probably won’t develop more intelligence and problem-solving capability than we need on average. Yes, here and there we produce a Goethe or an Einstein. But most of us are just smart enough to get along and pay our taxes. So the bet is that, unless there’s a planet out there with conditions so bizarre or a society so complex that children are required to invent their own form of calculus right out of the cradle just in order to survive, there’s probably an upward limit to the brain power that any extraterrestrial species will develop, too.
We still might meet our masters out among the stars. But I would bet on that differential intelligence being on a recognizable scale. They probably won’t be gods, and we probably won’t be worms on their sidewalk.
All by ourselves, we humans had to stand up to the other primates, learn to dig the soil to manage the useful plants, learn to tame and care for the useful animals and build fences against the rest, make meaning out of scratches in clay, build interfamilial trust, organize societies that stretched from one end of the river to the other, and create a destiny for ourselves. No gods from beyond the stars were needed for that. We’re smart enough, now, to figure out the rest on our own.
1. See There’s a worm in the street …. I find this an incredibly demeaning view of humanity and its achievements. We are not worms! Not even close!