Immortality. Sean Carroll roughly calculates it

Holiday Message 2023 | Reflections on Immortality – Sean Carroll (

I love taking things that people propose and putting numbers to them. Sean Carroll does that with the possibility of living forever. Along the way, he makes some points about how it feels to him and what it means as a meaning-making human.

He gets going on the calculations around a half hour in. He explains how live in a universe will be empty space one day, and how now, we are getting energy from sun, providing us a low entropy state. And he needs to define just how much energy a life uses up. He says, " To be alive, to be human, to be a living organism in the way that we think about it, it is necessary for time to pass and for you to accumulate memories and experiences and knowledge, as well as making predictions about the future."

In the end, he comes up with, a limit, " So if we did nothing, but harness all of the resources in the observable universe and put them to the task of thinking, of acting like human beings, whatever that means, to think and learn and love and write poetry and whatever, you could do that for 10 to the 93 human life equivalents, which it’s not realistic that, but that’s the upper bound writing to be realistic"

And, " , it doesn’t matter how clever you are, it doesn’t matter how you marshal the resources around you to sort of say, “Well, I’m gonna build a bunker, I’m gonna pack enough food to last longer than the universe,” etcetera, etcetera, you can’t do it"


For me, 10 to the 2 is just fine.