There’s an interesting post over at Sentient Developments about the simulation argument.
The SA essentially states that, given the potential for posthumans to create a vast number of ancestor simulations, we should probabilistically conclude that we are in a simulation rather than the deepest reality.
Most people give a little chuckle when they hear this argument for the first time. I’ve explained it to enough people now that I’ve come to expect it. The chuckle doesn’t come about on account of the absurdity of the suggestion, it’s more a chuckle of logical acknowledgment — a reaction to the realization that it may actually be true.
In a little more detail, the idea is this: right now we humans run simulations in our computers. Sometimes they’re very precise models of scientific phenomena, designed to study the universe or help engineer complicated pieces of equipment like airplane engines or submarine propellers. Some simulations are less complicated and we run them for fun, like The Sims, Sim City, or Roller Coaster Tycoon. Eventually – or so the argument goes – our understanding of biology and our computing power will grow to the point that we can run neuron-by-neuron or atom-by-atom simulations of people who are thus indistinguishable from you and me.
And nothing stops those people from building their own computers in their own simulated world, simulating their own sub-Sim people as well. And so on.
Given all these simulations nested like Russian dolls, what are the odds that we’re the people on top – the “real” people in the real world? Therefore we’re probably actually simulated beings being processed on a computer in somebody’s PC.
Ok, sounds plausible enough. Looking deeper though, there’s some good reasons to think it’s not true. The biggest is our own experiences with simulation. In living creatures a lot of very complicated chemical processes are ongoing all the time. To simulate these processes with any degree of precision – and not even from first principles – requires a vast, vast amount of computing power. The Folding@Home project uses the services of millions of linked computers just to adequately simulate the motions of individual protein molecules. To simulate the atoms in an entire human being would require an improvement in computational power by a factor of Avogadro’s number. Multiply by 6 billion for the rest of the people and you’re still nowhere close to done. You still have an entire planet or more to simulate in order for them to have a place to live.
Or maybe you’re willing to cut corners and only simulate things on a neuronal level. That doesn’t help all that much. Not only is neuron simulation very difficult, but you still have to simulate the external world in great detail in order to be able to feed those neurons some sensory data. And you have to coordinate between all six billion neuronal simulations and pretty soon you’re having the same problems as a full atomic simulation. Now there’s been some success simulating smaller neural systems, and that will certainly lead to success with larger systems. But there’s a big difference between simulating a slice of rat cortex and keeping track of the vastly, vastly more complicated human cerebellum – to say nothing of the fact that you still have to simulate a world for your Sims to live in and build their own Sims. A simulation of the neurons alone won’t work.
And once your simulations build computers and start simulating more people, things get out of hand. It’s not at all far-fetched for those six billion to want to simulate their own worlds, so you’ve squared the computational capacity you need. Keep going and you further exponentiate. The top-level computers are going to start smoking and sputtering pretty soon.
If indeed the first-level simulation is even possible itself. The speed of light, the granularity of atoms, and the fuzziness of quantum mechanics have already begun to stall out our own ability to make computers faster. There’s a reason clock speeds have been stuck around 3GHz for a while now, and though they become more efficient and are tied together in parallel the speed of light puts hard limits on how fast they can transfer information between each other. Now there’s no requirement the simulation be in real time, you might take years to simulate a second in your SimUniverse. But you’re going to run out of seconds eventually, the universe isn’t going to last forever.
Well, maybe higher-order Sims who are simulating us have physical laws better suited for building computers. Maybe, but at that point it starts to sound less like the Simulation Argument and more like the Simulation Late-Night Stoner Discussion.
And furthermore all this assumes that conscious experience can be simulated in the first place. I’m in a minority in my view, but I suspect it can’t be for philosophical reasons not far removed from the zombie argument. Which itself has no lack of legitimate criticisms, but that’s a topic for another day.
Back to the article. What are the consequences of the truth or falsehood of the simulation argument?
If it’s true:
If we were ever to prove that we exist inside a simulation, it would be proof that the transhumanist assumption is correct — that the transition from a human to a posthuman condition is in fact possible. But that will be of little solace to us measly sims! The simulation — er, our world — could be shut down at any time. Or, the variables that make up our modal reality could be altered in undesirable ways (e.g. our world could be turned into a Hell realm).
Pretty typical stuff. And though the article’s next paragraph skirts the idea, I note that accepting the simulation argument isn’t all that far removed in concept from accepting the ontological-style arguments for God. Skepticism about God should (in my opinion, though it probably doesn’t in practice) imply skepticism about nested simulations. For that matter belief in God should imply skepticism about nested simulations as well, since an omniscient being wouldn’t need to simulate anything in the first place.
If not true:
Now, on the other side of the virtual coin, should we ever prove that we are not in a simulation, that would also be bad. It would be potential evidence that the transition to a posthuman condition may not be possible…
Similarly, we should be disturbed that we are not in a simulation because it may imply that we don’t have a very bright future — that civilizations destroy themselves before developing the capacity to create simulations. Otherwise, we have to take on a exceptionally optimistic frame and assume that we’ll survive the Singularity and be that special first civilization that spawns simulations. Again, a probabilistically unsatisfactory proposition.
Or as I said, it could mean merely that large-scale simulation is not feasible. You can still have a bright future without that kind of computational capacity. It does mean the rapture-of-the-nerds style Singularity is less plausible, but I don’t see that as a great loss. Technology doesn’t need to be magic to be cool and useful.
So that’s something to think about. It’s not observable, testable, or repeatable and so it’s not really worth worrying about too much. But I’d say it’s still interesting to think about.