Bostrom imagined extraterrestrial civilizations running computer programs that somehow produce experiences such as you and I are now having, calling these "ancestor simulations." I may merely quote a brief passage from Bostrom's original paper to show the sophistry of its reasoning.
"A technologically mature 'posthuman' civilization would have enormous computing power. Based on this empirical fact, the simulation argument shows that at least one of the following propositions is true: (1) The fraction of human-level civilizations that reach a posthuman stage is very close to zero; (2) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero; (3) The fraction of all people with our kind of experiences that are living in a simulation is very close to one."
This cannot be careful reasoning, because Bostrom has sloppily spoken as if an interest in running “ancestor-simulations” is equivalent to actually running them. But there are 1001 reasons why extraterrestrial civilizations might not run such “ancestor-simulations,” even though they had some interest in running them if it was possible. He also does nothing to justify his claim that “at least one of the following propositions is true,” and it is certainly not clear that the third proposition is even possible, let alone that it must be true if the other two propositions are false.
Bostrom also makes the big mistake of implying that if there is one alien civilization interested in creating an “ancestor simulation,” that such a civilization would now be producing countless such simulations. He suggests that if there is one such civilization, the number of simulated lives would greatly outnumber the number of real lives. This is a completely unjustified insinuation. The more often some weird non-essential project has been done, the less people tend to be interested in doing it. If an alien civilization were able to run some ancestor simulation of the type Bostrom imagines, we have every reason to suspect that it would grow bored with such a thing after some particular number of years, and lose interest in it. Given an alien civilization that had one point in its long existence had an interest in running an ancestor simulation, there is no reason to think (given a very long lifetime for that civilization) that it would now be running such simulations. And there is also no reason to believe that it would now be running very many such simulations, so many that the number of simulated lives would outnumber the number of real lives.
Moreover, if we were to be living in a simulation, there would be no reason to believe that there are any extraterrestrial planets that might have super-advanced civilizations doing computer-generated "ancestor simulations," because a consequence of such a hypothesis is that all of our astronomical data (and all of our computer progress data and all of our video game progress data) is illusory, and that the stars and planets and computers and video games we observe are just "parts of the simulation." So the simulation argument is like some guy who climbs up a ladder and then kicks the ladder out from under his feet. If you exist in a simulated reality, then you have zero basis for believing anything about extraterrestrials or computers outside of your simulated reality.
A general rule of all successful arguments is: the conclusion never discredits one of the premises. Below is an argument that violates that rule:
Premise 1: My husband is a good man.
Premise 2: Good men tell the truth.
Premise 3: So when my husband said, "I'm going to flatten you!" when I told him I had thrown away his big stack of porn magazines, he must have been telling the truth.
Conclusion: Therefore, my husband literally plans to flatten me, perhaps by renting a streamroller vehicle, and running over me.
One reason this is a bad argument is that the conclusion invalidates one of the premises (if your husband is planning to murder you, then he's not a good man). Something similar goes on in the argument that we are living in a computer simulation, which could be stated like this:
Premise 1: We have astronomical reasons for thinking maybe there are very old extraterrestrial civilizations.
Premise 2: Such civilizations would have incredibly powerful computers.
Premise 3: Such computers would be so powerful they could simulate our lives.
Conclusion: We're probably living in a computer simulation run by extraterrestrials.
In this case, as in the wife's argument, the conclusion discredits one of the premises. If we are living in a simulated reality, then all of our astronomical data is just "part of the simulation," and we have no reason for thinking there are old extraterrestrial civilizations.
“The strongest argument for us being in a simulation probably is the following. Forty years ago we had pong. Like, two rectangles and a dot. That was what games were.
Now, 40 years later, we have photorealistic, 3D simulations with millions of people playing simultaneously, and it's getting better every year. Soon we'll have virtual reality, augmented reality.
If you assume any rate of improvement at all, then the games will become indistinguishable from reality, even if that rate of advancement drops by a thousand from what it is now. Then you just say, okay, let's imagine it's 10,000 years in the future, which is nothing on the evolutionary scale.
So given that we're clearly on a trajectory to have games that are indistinguishable from reality, and those games could be played on any set-top box or on a PC or whatever, and there would probably be billions of such computers or set-top boxes, it would seem to follow that the odds that we're in base reality is one in billions.”What Musk describes is a progression of sophistication in video game technology. But we have not one bit of evidence that any computer or video game has ever itself had the slightest iota of experience, consciousness, or life-flow. We only have evidence that biological creatures such as us can have some experience, consciousness, or life-flow. So there is no basis for thinking that some super-advanced alien civilization could ever be able to produce computers or video games that by themselves were the source of experiences like the ones we have. Making such an assumption based on an extrapolation of technical progress in video games is as fallacious as arguing that one day video games will be so realistic that their characters or creatures will leap out of the video game screen and endanger your life (kind of like in the visual below).
Musk's witless reasoning along the lines of "we're probably in a computer simulation because video games are getting better" has recently been repeated by a computer science expert named Rizwan Virk. Regarding the possibility that we are living in a computer simulation, Virk has deluded himself into believing that "there is plenty of evidence that points in that direction" (there is actually no such evidence). After making a completely inappropriate appeal to quantum mechanics and Schrodinger's cat, which have no relevance to this question, Virk tries to back up the simulation argument by telling us that physicist John Wheeler made the "discovery" that everything is information. That was merely a speculation of Wheeler's, one that hasn't won much acceptance; and if it is true, it wouldn't imply we are in a computer simulation. Virk also tries to back up the simulation idea by arguing that video games have got a lot better over the years. It's the same bunk argument presented by Musk.
Arguments that we are living in a computer simulation have very little intrinsic worth. But there is one good thing about considering such arguments seriously. If we consider seriously the possibility that we are merely living in a computer simulation, our minds may be opened to an important general possibility that may very well be true: the possibility that reality is radically different from the way we it is officially portrayed.
Let us consider one way a person might think about the possibility we are living in a computer simulation. He might think like this:
“We have been told that our minds are being produced by our brains, but that may not be true.
We have been told that we are merely the product of blind evolution, but that may not be true.
We have been told that the matter we see around us exists independently of our minds, but that may not be true.
Maybe instead of being just the result of a long series of incredibly improbable accidents, we are here because of the intention of some purposeful intelligence.
Maybe we're just living in a computer simulation run by extraterrestrials.”
The last of these ideas is not a very viable one at all, but the preceding ideas are all well worth considering, particularly in forms outside of the “computer simulation” idea. Considering such possibilities very seriously would seem to be a step in the direction of philosophical maturity. Once someone starts reasoning along the lines above, he may climb out of the thought prison that our mainstream experts have kept us chained in for so long. But having escaped such a prison, you should explore around and look for something better than the cheesy "we are in an extraterrestrial computer simulation" idea.