Nick Bostrom

And you could indeed imagine many possible motivations.

One would be just entertainment.

And you could imagine other, like maybe some kind of research, like historically, maybe it would be interesting to explore counterfactuals of history, or you could imagine art projects, or you could imagine moral reasons for... I think we know rather little about

the psychology and motivations of these hypothetical post-human civilizations and why they would make simulations.

There certainly is sort of empirical premises that flow into the simulation argument.

And so evidence for or against the truth of those assumptions, you know, would be relevant to evaluating the argument.

So one empirical premise is,

is that a technologically mature civilization would indeed have the capability of creating ancestor simulations and indeed to create lots of them.

And so the kinds of evidence that would be relevant for that is evidence, say, of the kinds of computational performance you could get from physically possible systems.

We're not able to build them currently, but we can kind of do first principle modeling of different systems

and so forth, and we can place lower bounds on the kind of compute power that they would unlock.

So that would be one element that would flow into this.

Another would be some estimate of the computational cost of running an ancestor simulation.

I think the largest part of that cost is the cost of simulating human brains at the sufficient level of detail that the simulation would be conscious.

And we can obviously not precisely determine what the computational expense of simulating a human brain is, but we can place some upper bound on that.

We have various views about what computational tasks the human brain is capable of performing.

We know how many neurons there are, how many synapses, how often they fire.

We can roughly estimate that.

Now, it turns out that if you estimate the amount of compute power available, even if you make rather conservative assumptions about that,

And then you make conservative assumptions about how much it takes to simulate one human brain and therefore how much to simulate all of the human brains.