Do you ever wonder about the meaning of life, and in particular your life? Well, of course you do, but maybe you should ease up on the angst. There are academics who say you don't have a life. You're just an app.
This disconcerting idea has been most famously promoted by Nick Bostrom, a philosopher at Oxford University. It goes like this: Everyone knows that historically, as computers became more powerful, programmers started making simulations -- mimicking real-life situations in software. Scientists modeled everything from pandemics to planet formation. Soon complex and compelling societal models such as Will Wright's SimEarth and its brethren emerged.
The characters in such sims were not very clever -- they didn't think. They simply reacted to your keyboard strokes or joystick moves with algorithmic behavior.
But now consider what might happen a few hundred years down the pike, when a simulation can be populated by avatars with advanced artificial intelligence. The characters can act in their own interests, and transcend the hard-wired intentions of the programmer. Presumably, at some level of complexity they become self-aware.
Taking this to its seemingly logical conclusion, a future historian (or curious teenager) wielding programming skills and access to a honking big computer could construct SimEarth on steroids. They could, for example, run a simulation of 15th century European society to see what it was like during the era of the Black Plague: a so-called ancestor simulation. Unlike Keanu Reeves in The Matrix, the people in the simulation wouldn't know that their lives were merely code running in a machine.
Now if it gets this far, you can bet that the coders won't run merely one simulation. Someone who has Grand Theft Auto on their machine doesn't play it just once. They play it a gazillion times. In other words, if ancestor simulations are possible, then they will greatly outnumber real societies. Consequently, it's very probable that all humanity is in a simulation -- that we didn't get one of those rare lottery tickets that would make us a real society of real beings. Everything you do today (and have ever done) could be just an illusion coded up by some clever Klingon.
You may be distressed by the idea that you're no more than software running in a computer. You may be dismissing the whole idea as nuts. But if you're not in a simulation, then Bostrom notes that either one or the other of the following must be true:
(1) The technological level of real societies never gets much farther than 21st century Homo sapiens. The aliens (not to mention our descendants) all self-destruct before developing the compute power that would allow ancestor simulations. If this is the way of things, then maybe you're real. But you'll also have to expect an imminent end to human society. Sell your real estate.
(2) A second possibility: Maybe lots of societies do develop the ability to make simulations, but for some weird reason, they don't. They're not interested. They're never interested. Personally, I find this hypothesis harder to swallow than a cookie with thumb tacks.
The alternatives to simulation don't sound very convincing.
Bostrom's hypothesis is unsettling. It also prompts a few obvious questions: To begin with, is there any way to know whether life is real or fake?
Silas Beane, a physicist at the University of Washington, has considered how a careful study of cosmic rays might tell us if a computational grid underlies our perceived experience. Such a grid is used by virtually all computer modelers, and serves to break down phenomenon into discrete chunks. Well, it turns out that if this grid is fine enough -- if the matrix has enough points -- our physics experiments, including the delicate cosmic ray tests, won't sense it. There may be no experimental way to tell if you're real or merely Memorex.
As a second question, what about the guys (terrestrial or otherwise) who built the sim we're living in. Who's to say that they're not a sim? And if they are, what about the guys who built them?
Bostrom deals with this barber shop mirror problem by noting that there's a limit to how far down the sims can go. It's a limit imposed by cost. After all, you could have a version of Grand Theft Auto running inside the game itself, and maybe one inside that. But you can't do this ad infinitum because of the computational costs. Somewhere there has to be a basis reality.
When I talked to Bostrom about this idea several years ago, I asked him this: If I'm merely a simulation, do I have an obligation to behave ethically? What's the point of worrying about social niceties if I'm just code? After a few moments' hesitation, Bostrom quietly suggested that I should opt for moral behavior.
Sure, but maybe he was programmed to say that.
Mulling it all over, I'm not entirely happy with the thought that I might be lowlier than a lab rat. At least a lab rat is real.
No... wait a minute... maybe it's not.