Nick Bostrom

And so it looks like that's not... If it happens several times independently on Earth, then it can't be that unlikely.

And so it looks like that's not... If it happens several times independently on Earth, then it can't be that unlikely.

But anyway, it poses some constraints.

But anyway, it poses some constraints.

You can simultaneously believe that it's easy for intelligent life to evolve and that it's technologically feasible to do large-scale space colonization and also believe that there is a wide range of different motives present amongst advanced civilizations while at the same time explaining why we haven't seen any.

You can simultaneously believe that it's easy for intelligent life to evolve and that it's technologically feasible to do large-scale space colonization and also believe that there is a wide range of different motives present amongst advanced civilizations while at the same time explaining why we haven't seen any.

So something has to give, and it gives us clues.

So something has to give, and it gives us clues.

The other...

The other...

that I was referring to, the Carter-Leslie-Doomsday argument, it's a piece of probabilistic reasoning having to do with how to take into account evidence that has an indexical element.

that I was referring to, the Carter-Leslie-Doomsday argument, it's a piece of probabilistic reasoning having to do with how to take into account evidence that has an indexical element.

So indexical information is information about who you are, when you are, or where you are.

So indexical information is information about who you are, when you are, or where you are.

the methodology for how to, the epistemology of how to reason about these things is quite difficult and murky.

the methodology for how to, the epistemology of how to reason about these things is quite difficult and murky.

So it's unclear whether the Carter-Leslie-Doomsday argument is ultimately sound or not, but I can give you a kind of intuition for how it would work.

So it's unclear whether the Carter-Leslie-Doomsday argument is ultimately sound or not, but I can give you a kind of intuition for how it would work.

So let's explain it by means of an analogy.

So let's explain it by means of an analogy.