Nick Bostrom

But then the doomsday argument says that, well, there's one more really important piece of information you have here, which is that you can observe your own birth rank, your sequence amongst all humans who have ever been born.

But then the doomsday argument says that, well, there's one more really important piece of information you have here, which is that you can observe your own birth rank, your sequence amongst all humans who have ever been born.

And so this turns out to be roughly 100 billion.

And so this turns out to be roughly 100 billion.

That's roughly speaking how many humans have existed to date on Earth.

That's roughly speaking how many humans have existed to date on Earth.

And so the idea then is that if humanity goes extinct relatively soon,

And so the idea then is that if humanity goes extinct relatively soon,

then you will be a relatively, like being number 100 billionth of, say, 200 billion humans is very unsurprising, right?

then you will be a relatively, like being number 100 billionth of, say, 200 billion humans is very unsurprising, right?

That's like corresponding to getting ball number eight from an urn that has 10 balls, you know, or 16 balls or something like.

That's like corresponding to getting ball number eight from an urn that has 10 balls, you know, or 16 balls or something like.

So the conditional probability of you observing having the birth rank you have, given that there would be relatively few people in total,

So the conditional probability of you observing having the birth rank you have, given that there would be relatively few people in total,

that conditional probability fairly high.

that conditional probability fairly high.

Whereas the conditional probability of you being this early, if there's got to be quadrillions of humans spreading through the universe, very improbable.

Whereas the conditional probability of you being this early, if there's got to be quadrillions of humans spreading through the universe, very improbable.

Like a randomly selected human would be much more likely to live much later in life on some faraway galaxy.

Like a randomly selected human would be much more likely to live much later in life on some faraway galaxy.