Life's a sim and then you're deleted

by Nick Bostrom

OF COURSE you thought The Matrix was fiction. But only because you were meant to. Do you think they're stupid enough to let us realise what's really going on?

It usually takes a conspiracy theorist to hatch such a far-fetched plot. But Nick Bostrom is a philosopher at Yale University, and he believes the Hollywood blockbuster is closer to the truth than many of us would care to believe. He's done the calculations, and he reckons that we could well be living inside a simulation.

That's right. Your life might actually be a computer program developed by a post-human society living in what you think of as the future.

In a paper submitted to the journal Mind, Bostrom has outlined exactly how he reached this chilling conclusion. The reasoning starts with one simple premise. At some point, civilisation will develop enormously powerful computers capable of mimicking what we call consciousness. And if that premise is true, the rest follows logically.

Outrageous? Not a bit of it. Look at it rationally. If it becomes technologically possible to mimic consciousness, the future can only pan out in one of three ways. First, some extinction event - maybe a powerful but deadly technology, maybe a natural disaster - will wipe us out before we actually do it. If that's true, then you can relax. What you're experiencing right now is real life.

The second scenario is also a comforting one: future humans won't be interested in running simulations. They might be too sophisticated to bother with such games, or there may be laws against it. But do either of those noble outcomes sound like a probable future of human civilisation to you? Thought not.

Which leaves us with the least palatable option: humans will one day simulate consciousness, and then go on to create simulated Universes for it to live in. If that's true then the chances are they've already done so, and you're living in one.

OK, it's just possible that you're part of the pre-simulation real world - what Bostrom calls the "original history". But given how many simulations there'll be, the probability of that is very slim. All things considered, Bostrom says, the probability that you're living in a simulation is "close to unity". "I think the argument is watertight," he says.

Any logical argument, of course, is only as good as its premises. But Bostrom has got that covered too. Imagine that we do indeed live in the "original history". How likely is it that we're on the trajectory leading to computers that can mimic consciousness?

According to Bostrom, very, very likely. All you need is to discover the particular type of computational processes that leads to what we call consciousness. "A computer running a suitable program would be conscious," Bostrom says. Roboticist Hans Moravec of Carnegie Mellon University in Pittsburgh has worked out that, whatever the "suitable program" turns out to be, emulating a mind would take about 1014 operations per second. That seems like a lot now - today's fastest computers struggle to get above 1012 operations per second - but we're heading in the right direction.

As Bostrom points out, big thinkers such as Ray Kurzweil and Eric Drexler already argue that we haven't yet squeezed the full potential out of our existing computing resources. Today's nanotechnology would let us build a system the size of a sugar cube that would perform 1021 operations per second. And a computer with a mass equivalent to a large planet could do 1042 operations per second. We might even be building such systems by the end of the century. Even if we discount the possibility that new physics could lead to super-powerful methods of computing, our current technology is already leading us towards a mind-emulating future.

Once there's enough computing power to simulate consciousness, creating an environment for it to interact with will be child's play. For one thing, simulating an entire Universe down to the minutest level would be a waste of resources. You would only need to simulate to a degree where the universe's inhabitants didn't notice any irregularities (remember those "disturbances" in the matrix). So, for example, there'd be no point filling in every microscopic detail, or the minutiae of distant astronomical objects, until someone decided to look at them. Then the creators could fill in the necessary details on an ad hoc basis.

Obviously, the view has to be convincing, but there's no way the observer can know how these things ought to look or behave. It's quite likely a consciousness looking at odd features in the microscopic world of atoms and electrons would accept any bizarre irregularities at this level as "just the way things are".

If you've ever wrestled with the weird nature of quantum mechanics, alarm bells may just be starting to ring...

So what shall we do? Bostrom thinks we should keep calm and act normally; there's certainly no need to flip out. "Anyone who started to change their life because of this would be a mad loony," he says.

But Robin Hanson, an economist at George Mason University in Fairfax, Virginia, doesn't agree. He argues that you should alter your behaviour radically: if your life is just a computer simulation, you need to do everything possible to make sure you're not deleted.

First you need to work out the purpose of the simulation. If it's for entertainment then you'd better make sure you're part of the fun. What that means varies across cultures, so to be safe you should be funny, outrageous, violent, sexy, strange, pathetic and heroic all at once - "in a word 'dramatic'," Hanson says.

If the simulation is for the creator to participate in, then they're probably going to want to rub shoulders with the rich and famous, or even play a famous person. So you'd better be the life and soul of the party, and - most important of all - suck up to celebrities. But if the simulation is for the creator to play God, punishing and rewarding minions' behaviour, you'll do well to live a blameless life instead.

And one more thing: don't be tempted to breathe a word about this to anyone. Hanson says that if everyone knows they're in a simulation, the whole thing will start to look stilted and staged, and the creator is likely to pull the plug. Keep it to yourself, or tell only a few close friends. Then you can get on with finding a purpose to your so-called lives: escaping.

Entertaining though it might be, Bostrom thinks Hanson's advice is useless because it's almost impossible to work out what our world is for. "We don't have any direct access to how the simulators set it up," he says. "The least misleading advice would be to get on with your business as you would have done before."

He even thinks it would be OK for everyone to know what's going on. "Presumably in the original history there were people who had these crazy ideas," he says. "If you were trying to run as realistic simulation as you could, you wouldn't want to ban that."

Maybe he's right. After all, millions of us sat through The Matrix without them pulling the plug on us. And nobody panicked at the idea that the Earth was a simulation created by a future civilisation intent on tapping our bodies for energy. But what did Bostrom think when the film came out? Was he impressed by its veracity? Not really. "Using humans as an energy source is ridiculously implausible," he says. "But that's Hollywood for you."