Nick Bostrom

So that means it's not true that almost all civilizations at our stage failed to reach technological maturity.

Some non-trivial fraction make it through.

Then let's suppose that the second alternative is also false.

So amongst those who do become technologically mature, some non-trivial fraction remain interested in using some of the resources to create these kinds of ancestor simulations.

then you can show that the kind of computational resources a mature civilization would have would suffice to create millions and billions of detailed simulations, ancestor simulations, runs of human history.

And so that if the first two alternatives are false, then

there would be many, many more simulated versions of people with our kinds of experiences than there would be original, implemented in basic physical reality people with our experiences.

And conditional on that, if almost all people with our experiences are simulated, we should think we are probably one of the simulated ones rather than one of the rare non-simulated ones.

So that means that if you reject the first two alternatives,

you would then have to accept the third one.

And then that shows that it's not the case that all three of them are false.

So hence, at least one of them is true.

So that's the structure.

Well, so that's the second, right?

I mean, so if all of these technologically mature civilizations are completely uninterested in simulating,

then that would be possibility number two.

But note that for the second alternative to hold, it's not sufficient that most of them are not very interested.

Because even if it were just a 1% of these mature civilizations that were even a little bit interested, they still could produce millions of them.

And so that would have to be this extremely strong convergence.

Like almost all of them would completely have to lose any interest in doing this in order for the second alternative to be there.