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An Exterminator-Free Galaxy

Quoting Nick Land, expat Brit philosopher in Shanghai, “The cosmic reality visible to us is characterized by an intense, efficient aversion to the existence of advanced civilizations.” He calls whatever it is that prevents the existence of advanced civilizations “The Great Filter.” Longtime science fiction readers familiar with Gregory Benford’s Galactic Center series or Fred Saberhagen’s Berserker universe will understand what Land means when he dubs the Great Filter “the Exterminators:” Killer robots sent out to destroy advanced civilizations.

But on the bright side, Exterminators probably don’t exist, because if they did, the human race would already be extinct.

You might have heard of Von Neumann probes. A self-replicating interstellar probe journeys to a nearby star, makes copies of itself, and those copies journey to nearby stars. Repeat until you have a probe in every stellar system in the galaxy. Even if the probes’ net velocity is only 1% of the speed of light, they would reach every star system in the galaxy within 10 million years.

Given that the galaxy is about 13.2 billion years old, filling the galaxy with self-replicating probes would take but a moment of astronomical time. Look at it this way: if Earth is typical, and a planet needs to exist for (rounding) 4.2 billion years for intelligent life to develop a civilization capable of launchign a self-replicating probe, then it would take just one alien civilization arising in our galaxy in the last 9 billion years for there to be a probe somewhere in the solar system right now.

Now suppose that one alien civilization built probes with a straightforward mission: destroy other intelligent species while those intelligent species are stuck on their home planet, to ensure that one civilization can exploit all the resources of the galaxy. If true, their killer probes would have destroyed us a long time ago. Maybe even before there was an us.

Since that clearly didn’t happen, we conclude that zero alien civilizations built Exterminators.

Wait, their killer probe might be here, waiting to destroy us
No, because the Exterminator has nothing to gain by waiting. Over three thousand years ago, human beings built plainly artificial objects visible from low earth orbit. A clear signal that a species had evolved tool use and enough social organization to engage in massive engineering projects. Why wait to destroy that species? Maybe it will take four thousand years for that species to build its own Von Neumann probes, but what if it takes them four hundred? Or forty? Don’t take that chance. Destroy them now.

Since ancient Egypt wasn’t wiped out by a hundred-mile-wide asteroid impact, the sun going nova, or a never-ending army of implacable battle robots, “no killer probe” is the safe bet.

What does this mean?
Looks like the Great Filter lies behind us. Whether life is rare, or planets rarely stay habitable for billions of years, or the metabolic expense of intelligence rarely conveys a selective advantage, or tool use is rare, doesn’t matter. We are probably the only intelligent tool-using species in the galaxy. The handful of human beings who will ever get past low earth orbit will be like the Aborigines crossing the Torres Strait or the First Nations pushing south of the Ice Age glaciers, entering a vast, resource-rich realm without competition.

Except with each other, which for science fiction writers is a good thing. Fodder for a million stories….

Speaking of which, I should get back to work. Till next time.