Can you trust your senses? Are there real, conscious people around you, instead of just holograms or zombies? Are you a real person?
It’s easy to dismiss these questions. Usually for two reasons:
- “Sure, all sorts of crazy things could be true. But those are just speculations.”
- “Yes, I might be deceived right now. But how does that affect my life? What can I do, other than just live normally?”
The beauty — or horror — of the Simulation Argument is that it avoids both objections:
- It’s not just a speculation.
- If you might be in a simulation right now, then you actually should live your life differently.
Unfortunately, when you hear about the Simulation Argument, you often don’t see those replies stated in their strongest way.
I’ll state a version of the argument.
The Empirical Premise: Most of the “people” who think they’re real, flesh-and-blood humans are actually conscious computer programs.
The Indifference Premise: If most people are simulated, then you are probably simulated.
The rationale behind the Empirical Premise is that (1) our descendants will likely have access to the computing power necessary to run conscious computer programs who believe they’re real humans, and who populate simulated environments that appear real; and (2) these descendants will actually want to run at least two instances of such programs, either for historical, recreational, or scientific purposes. For example, they might simulate the 21st century itself, even though they (and we, as simulations) actually live in the 21st century.
If so, then since there’s only one real instance of the 21st century, most of the perceived instances of this century will be simulated. And the simulators might have the computing power to run millions of simulations at once. In that case, it would be a huge coincidence that you just happen to be living in that one, real, original instance of this century.
The idea behind the Indifference Premise is simple: If most people have some feature, then absent other evidence, you should guess that you probably have that feature.
Some Failed Objections to the Argument
- “Is it really possible to build a computer powerful enough to simulate a mind?” Answer: Yes; we at least have computers that can perform as many operations per second as the human brain does.
- “Is it really possible to build a computer powerful enough to simulate an entire universe, down to the quantum level?” Answer: We don’t need to, because we only need to simulate whatever human beings are actually, presently perceiving.
- “Isn’t it morally questionable to subject people, against their will, to such experiments?” Answer: Good thing no one ever acts immorally.
- “How would the simulators know what the real instance of this year was like?” Answer: They don’t have to; we wouldn’t know the difference.
- “How would the simulators avoid the problem of glitches in the program?” Answer: If such glitches appeared, the simulators could simply edit our memories so we don’t remember them.
- “Would the simulators really allow us to realize that we’re in a simulation?” Answer: Depends on their purposes. If it’s entertainment or research, then sure. If it’s a historical simulation of this year, then if people in the original, real occurrence of this year suspected that they might be simulated, then the simulators would let us (simulations) suspect that, too.
- “Wouldn’t the simulation be boring to watch?” Answer: The simulators could fast-forward, or set notifications for interesting events, at their will.
- “Haven’t scientists proven that we’re not in a simulation?” Answer: No; they’ve proven at most that if we are in a simulation, the simulators haven’t let us know. Simulators can, of course, simulate experiences and memories of any scientific results they want. In fact, a case can be made that some scientific evidence actually supports the simulation hypothesis.
So it’s not so easy to avoid the conclusion that we’re probably in a simulation right now. Still, we have a few options left.
Some Better Objections
- “Is it even possible for a computer program to be conscious?”
Some experts say yes; others say no. Imagine a single atom of silicon or gold. How could that tiny object be conscious? Now make a big pile of such atoms. How could a big pile of unconscious silicon and metal (i.e., a computer) be conscious?
This objection may go too far. Compare: “Imagine a single atom of carbon, hydrogen, oxygen, or nitrogen. Surely that tiny object is unconscious. Now how could a big pile of such unconscious things be conscious?” Of course, another name for a certain pile of carbon, hydrogen, oxygen, and nitrogen is “a human brain.” Yet we probably agree that many human brains are conscious.
2. “The simulation hypothesis is more complex than the ‘real world’ hypothesis, because it requires the existence of a real world plus the existence of simulators. And Ockham’s Razor tells us to prefer simpler hypotheses.”
3. “It doesn’t feel as if we’re in a simulation. The world around me seems real.”
Yes; it’s just very implausible that we are living in a simulation right now. The people around us seem conscious and human. Most of us have the strong intuition that we live in the real world, maybe an intuition even stronger than the intuition that the Empirical Premise or that the Indifference Premise is true.
This objection depends on trusting such intuitions. Many experts are skeptical. Still, a case can be made that denying the reliability of intuitions is a big mistake. It might leave us in a position of global skepticism: the position that we aren’t justified in believing anything. If so, then we’d also have to be skeptical of the beliefs that led us to take the Simulation Argument seriously in the first place.
One last objection:
“Yes, I might be deceived right now. But how does that affect my life? What can I do, other than just live normally?”
Here’s the standard reply. Assume that you (like most people) want to prolong your life. Then you should think about what would lead to the end of your (simulated) life: the shutting down of the program.
Now what would the simulators be like? If they’re our descendants, then they might have similar attitudes to ours about morality and entertainment. If they would like to watch a simulation about a person like you, then they’re likely to prolong a simulation of you, and thereby prolong your life. You should want the simulators to like you, and to want to continue the simulation.
In turn, you should want to be an entertaining, likable, and morally good person. Of course, whether you think we’re in a simulation or not, that’s good advice.