Fermi and Tippler, or, Where is Everybody?
I have heard the argument made (by Tippler, I think) that self-replicating van Neumann style space probes, even at sublight velocities, since they theoretical can reproduce at a geometric rate, should have overrun the galaxy long ago, if ever an intelligent civilization had once created them.
This is an intellectual argument, the argument of a scientist, not of an economist. By an intellectual argument, I mean, an argument that does not take real-world limitations into account. I can just imagine a similar argument made before the invention of the Internet to prove that one virus would take over and crash all computer systems whatsoever. (Indeed, I am reminded of the Marxist daydream that says one business will eventually take over all others, buy up all land from pole to pole, and monopolize the world. Because business “inevitably” leads to monopoly, donchaknow).
Because when I contemplate the von Neumann machines, or, to use an SF example, the Monolith from Arthur C. Clark’s 2001: A SPACE ODYSSEY, I think, what are the costs versus the benefits? Because it costs something, time, resources, energy, whatever, for a self-replicating machine to replicate itself. What makes that cost-benefit outweigh the opportunity costs. Is there not something else the Monolith builders want to do with their resources?
Imagine this:
First, you are a Monolith sent out by the Forerunners. You land on Earth, but, instead of using your matter control beams to suck up the total mass of the nickel-iron core of the planet to creating a multimillion copies of yourself to send out to other worlds, you decided to settle down, start a small farm, think about abstract mathematics, write poetry, or play backgammon, and so you just stayed in hibernation mode with nine-tenths of your systems on standby, resting at the bottom of Crater Lake in Arizona, or in the Tunguska river bed in Siberia.
Why continue the mission? Is there some economic benefit to you? Is the a cost involved? Can you afford it? Are you required by law or programming to do so? What if your home planet is long dead, are you still bound by that law? How long before that programming mutates due to a computer hiccough, and you turn into the dread and dread NOMAD, whose mission is to sterilize all imperfect life forms?
Second, what if you had been sent out by a form of life, let us call them “The Flat Ones” who only live (Robert Forward style) on the surface of Neutron Stars. You are programmed to examine carefully the high-gravity environments where life, nine times out of ten, is known to evolve. Sometimes you check the photospheres of still-burning stars and the cores of superjovian planets. Now, it is known to your science that in .01 percent of cases life evolves in microgravity environments on small rocky worlds near small yellow stars, but the return on investment from such cases has historically been trivial: those carbon-based life forms don’t life long, they are warlike, and they don’t make good eating. Why would you bother looking there for them?
Third, what happens when some bright hive-mind of worm creatures from beyond the Crab Nebula finds out there is a rich source of materials to be had from these Forerunner Monoliths. All you need to do is crack open the black outside shell, and there is all sorts of subatomic computer circuits, energy batteries, star drives, and monolith-reproducing machinery for you to use. AND ITS ALL FREE!
Instead of making another van Nuemann Machine, you set your van Nuemann machine to make chessburgers, coca cola, and fine damascened gold. The Crab Nebula worms simply need to send out Monolith-lampreys to find the Monoliths, and they are as rich as Croesus.
Well, if the Monolith builders are still around, you do not have the Forerunners able to spread throughout the entire Galaxy in a few thousand years, you have them involved in something between a war and an arms race. They have to start equipping their Monoliths with weapons and evasion-systems, and they need to turn resources away from the search for scientific data to defense and offense against the Worms.
Then the Planet-Killers from Greg Bear find out about the Worm-Forerunner war, and it shocks them into warlike paranoia. They set about to find and destroy the Monoliths, raather than simply cannibalize them for parts.
You see the problem with Galaxy-should-be-filled-by-now-with-von-Neumann machines argument? The argument simply assumes a geometrical progression of effort from the Forerunners. If they have the technical capacity to fill up the world with machines, ergo (so he reasons) they would do so. I say that unless they had the economical and legal capacity to fill up the galaxy with machines, ergo (so I reason) they will not do so — not unless it is worth their investment. They may have other things to do with their time. If you create self-creating machines, you don’t have machines, at that point, you have an ecology.
About John C Wright
John C. Wright is a practicing philosopher, a retired attorney, newspaperman, and newspaper editor, and a published author of science fiction. Once a Houyhnhnm, he was expelled from the august ranks of purely rational beings when he fell in love; but retains an honorary title.
