[Paper] On the 'Simulation Argument' and Selective Scepticism

Jonathan Birch recently published an interesting critique of Bostrom's simulation argument. Here's the abstract:

Nick Bostrom’s ‘Simulation Argument’ purports to show that, unless we are confident that advanced ‘posthuman’ civilizations are either extremely rare or extremely rarely interested in running simulations of their own ancestors, we should assign significant credence to the hypothesis that we are simulated. I argue that Bostrom does not succeed in grounding this constraint on credence. I first show that the Simulation Argument requires a curious form of selective scepticism, for it presupposes that we possess good evidence for claims about the physical limits of computation and yet lack good evidence for claims about our own physical constitution. I then show that two ways of modifying the argument so as to remove the need for this presupposition fail to preserve the original conclusion. Finally, I argue that, while there are unusual circumstances in which Bostrom’s selective scepticism might be reasonable, we do not currently find ourselves in such circumstances. There is no good reason to uphold the selective scepticism the Simulation Argument presupposes. There is thus no good reason to believe its conclusion.

The paper is behind a paywall, but I have uploaded it to my shared Dropbox folder, here.

EDIT: I emailed the author and am glad to see that he's decided to participate in the discussion below.

Jonathan Birch recently published an interesting critique of Bostrom's simulation argument. Here's the abstract:

Nick Bostrom’s ‘Simulation Argument’ purports to show that, unless we are confident that advanced ‘posthuman’ civilizations are either extremely rare or extremely rarely interested in running simulations of their own ancestors, we should assign significant credence to the hypothesis that we are simulated. I argue that Bostrom does not succeed in grounding this constraint on credence. I first show that the Simulation Argument requires a curious form of selective scepticism, for it presupposes that we possess good evidence for claims about the physical limits of computation and yet lack good evidence for claims about our own physical constitution. I then show that two ways of modifying the argument so as to remove the need for this presupposition fail to preserve the original conclusion. Finally, I argue that, while there are unusual circumstances in which Bostrom’s selective scepticism might be reasonable, we do not currently find ourselves in such circumstances. There is no good reason to uphold the selective scepticism the Simulation Argument presupposes. There is thus no good reason to believe its conclusion.

The paper is behind a paywall, but I have uploaded it to my shared Dropbox folder, here.

EDIT: I emailed the author and am glad to see that he's decided to participate in the discussion below.

How did I lose the anthropic argument? We're still only going to know about the sort of universe we're living in.

The original form of the Bostrom thesis is that, because we know that our descendants will probably be interested in running ancestor simulations, we can predict that, eventually, a very large number of these simulations exist. Thus, we are more likely to be living in an ancestor simulation than the actual, authentic history that they're based on.

If we take our simulators to be incomprehensible, computationally-rich aliens, then that argument is gone completely. We have no reason to believe they'd run many simulations that look like our universe, nor do we have a reason to believe that they exist at all. In short, the crux of the Bostrom argument is gone.

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[Paper] On the 'Simulation Argument' and Selective Scepticism

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[Paper] On the 'Simulation Argument' and Selective Scepticism

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