Wednesday, July 12, 2017

We Are Not a Simulation

I have occasionally written (see most recently here and here) on the fascinating notion that the universe we live in is actually not "real" but is rather a computer simulation designed by some intelligent creatures living in a different world altogether. This theory has been popularized, perhaps most notably, by philosopher Nick Bostrom.

I find the theory fascinating not because I think it's plausible but because those who do are actually trying to account for the enormous amount of apparently intelligent engineering and design manifested by the fine-tuning of our universe without having to concede that theism is true. They are right, I think, to see an intelligence behind the universe, but wrong if they conclude that the intelligence is anything less than the maximally great being posited by theism.

There's a good article by computer expert Peter Kassan at in which he explains the simulation hypothesis and offers several criticisms of it.

Kassan gives us a summary of the argument for thinking we live in a simulation:
  • The universe contains a vast number of stars.
  • Some of these stars have planets.
  • Some of these planets must be like Earth.
  • Since intelligent life arose and eventually invented computers on Earth, intelligent life must have arisen and invented computers on some of these planets.
  • It is (or inevitably will be) possible to simulate intelligent life inhabiting a simulated reality on a computer.
  • Since it’s possible, it must have been done.
  • There must be a vast number of such simulations on a vast number of computers on a vast number of planets.
  • Since there’s only one real universe but there’s a vast number of simulations, the probability that you’re living in a simulation approaches one, while the probability that you’re living in the real universe approaches zero.
As Kassan observes there is no empirical evidence for, or testable implications of, this argument. It's therefore not a scientific hypothesis. It's more akin to science fiction or theology. Kassan calls it "cybernetic solipsism". There’s little reason, he says, to argue that anyone else in your simulated universe is conscious—to achieve verisimilitude, there’d be no need to actually program anyone else’s consciousness but yours.

More than that, though, even an immensely powerful computer would not be able to program human consciousness:
But even a superdupercomputer wouldn’t produce even a single conscious being. The crucial move in the argument is that the simulation of a human mind would actually be conscious in the same sense that you and I are. Your computer simulation wouldn’t simply behave exactly like a real person, it would actually feel pain, pleasure, lust, fear, anger, love, nausea, angst, ennui, and everything else you can feel. It would actually experience the same optical (and other sensory) illusions you do. It would feel what you feel when you get sick, or when you drink or take drugs. It would fall asleep and dream, and then wake up to realize that it was only dreaming. Presumably, it would even die.
In other words, the qualia of sensory experience would have to somehow emerge from the whirrings of the computer's hard drive, but a physical computer can only produce physical outputs, and our sensations - pain, color, sound, etc. - are not physical or material. They're produced by physical stimuli, they're generated by electrochemical reactions in our nervous system, but the sensation of blueness when we look at the sky, to take one example, is not itself physical.

Kassan looks at another aspect of the problem of how a material device like a computer can produce immaterial effects when he considers how a computer can generate what philosophers call intentionality:
The argument that a sufficiently complex computer program would be conscious in the same way you and I are goes something like this:
  • The brain is an information processor.
  • A computer is an information processor.
  • A computer can be programmed to process the same sort of information the brain processes in the same way that the brain processes information.
  • The conscious mind arises from information processing in the brain.
  • Therefore, a conscious mind will arise from equivalent information processing on a computer.
The argument depends crucially on the concept of information. A computer contains, processes, and displays data like a highway road sign consisting of a rectangular array of light bulbs. As we drive by, we can interpret the pattern of light as letters and words, but the message we read is actually nowhere contained in the display. Imagine a space alien interpreting the display as a binary code, with each column of eight light bulbs conveying one byte. How would they interpret a sign that to us read DANGER—CONSTRUCTION AHEAD? A computer is processing data (information) only because we interpret it as doing so; a brain behaves as it does without interpretation.
In other words, the arrangement of the bulbs in the sign has a meaning to us, but how do the reactions in our brains when we see the sign generate that meaning? The brain is just an enormously complex system of neurons. Where does the meaning come from? There's no meaning in the chemical reactions that fill the brain when we observe the sign. Nor does a computer generate meaning. It simply produces data. Meaning is the product of conscious observers.

Kassan finishes with a couple more thoughts about all this:
There’s another irony concerning the notion that we’re all just computer simulations. If you believe you’re living in a computer simulation, then everything you think you know about the world—including its vastness, the probability of intelligent life elsewhere in the universe, and even the very existence of computers—is part of that simulation, and so is completely worthless. The evidence on which the entire chain of reasoning depends, in short, is illusory—and so nothing at all can be argued from it.
None of our beliefs are reliable since they're all just beliefs we hold because we've been programmed to do so. Among those simulated beliefs are our moral beliefs:
If we believe we’re just simulations, how should we behave? Should we treat everyone around us as if they’re just a figment of someone else’s imagination, shamelessly manipulating them for our own pleasure or gain? Should we take careless risks, knowing we’ll live again in another simulation or after a reboot? Should we even bother to get out of bed, knowing that it is all unreal? I think not.
If the universe is a simulation then we're all programmed to live the way we do. No behavior is wrong in any meaningful sense. There's no free will, no morality, no meaning to our existence, no justice or injustice. We're all just actors on a stage manipulated by an intelligent programmer for his own purposes. Thus, there is nor can there be, any value to our lives. This, by the way, would be true as well if the programmer were a God who preordains every aspect of our lives.

Belief in a real world and other minds besides our own is properly basic. We are within our epistemic rights to believe that the world exists objectively unless and until we are confronted with a compelling defeater for that belief. The simulation hypothesis falls short of being a compelling defeater.