I'm going to pull the most important part of my response up to the top, because I think there's an important difference in your last comment that changes the fundamental nature of this argument. Which is to say, you've moved away from trying to argue a point that I will never agree with, to making an argument that is much closer to true, and to which I have more hope that you will agree with my response below.

> So in the long run we have to either die or stop having children. There is no other option.

This is a very different statement from your previous assertions that we have to die, period. You're now allowing for at least one other alternative; there are many more alternatives, many of which would be more palatable (to people today or more importantly to people millions of years from now), but now that you've allowed for at least one alternative, that substantially changes the nature of the "resource constraints" argument, and it's no longer framed as a unsolvable problem. That seems like progress.

If your argument had started out as "we need to avoid growing our resource usage exponentially for an unbounded amount of time", then I would have mostly agreed with you on that. (I would add caveats like "assuming nothing improves in our fundamental knowledge of physics that allows for more alternatives", but that does not invalidate the point.)

As a side note, having the resources to sustain biological reproduction is the least of the potentially exponential resource concerns that would apply in the kinds of hypothetical future worlds I'm talking about; another would be the expansion of resources used by individual people as part of their own subjective thoughts and perceptions, becoming more intelligent by having a literally more powerful brain.

(Please note that objections about why the specific alternative you raised seems unpalatable aren't needed here; the point was that you are now observing there's at least one alternative, and I'd be quite happy with the resulting reframing of the problem as one of not having exponential growth in an assumed-finite universe. There are many, many ways to address "don't grow exponentially without bound".)

To quickly outline other options, barely scratching the surface but making it clear there's depth here: once we start talking about the primary resource being some form of computation, other possibilities include sharing computational cycles and affecting subjective perception of time or speed of thought; think "time multiplexing" rather than "space multiplexing. (That's also making some assumptions about how time, physics, and computation will work, and I think it's reasonable to assume we still have a lot to learn about all of those things. Leaving aside the open question of whether the multiverse is finite.) I would also observe that the form and perception we will have millions or billions of years from now is likely to nearly incomprehensible and unrecognizable to us today.

> To realize your ambitions it is not enough for some humans to leave the planet. They all have to go. And not just the seven billion of us that are here right now, but the quadrillions or more that will exist after millions of years of exponential growth with no death.

Yes, that was the point: if the planet were no longer habitable and we could not fix that, the remaining people who had not already left for other planets or parts of space would have to do so at that point. (That is, again, assuming that in five billion years we still think that's the most reasonable way to solve the problem, as opposed to any of the other myriad options we may have at that time.)

"quadrillions" seem highly unlikely to be on this planet to begin with, even if we've built both up and down to its limits; long before we could be anywhere near that point, many will have already left the planet, if not the solar system.

Populations grow more slowly or not at all when people feel substantially safer. Also, see above.

> Actually, you know what this is like too. You just aren't extrapolating that experience

I have in fact done such reasoning, based on different premises and additional information you aren't including, and have thus come to different conclusions.

Becoming older will not change my goals, just my experience and relative capabilities. And I've already made advance commitments to consciously avoid letting myself become more cynical or jaded with age and experience. On the contrary, I find that my sources of novelty and happiness and hope tend to grow over time.

Also, lest you feel that I don't have any caution or acknowledgement of concern in the reasoning I'm doing: The scale of problems I'm talking about wanting to solve here do, in fact, require an abundance of caution and concern to reason about and solve. That caution goes into things like "how do we avoid horrible failure modes like 'just modify yourself to not get bored' and other paths that effectively lead to wireheading", and "will we get the logic right on a computer that ends up running a universe-scale simulation", and "how do we make sure the systems we build prevent any possibility of cascading failures, at least on par with the level of redundance and resilience demonstrated by biological systems", and "how do we prevent either the physical or digital equivalent of grey goo". See "Security Mindset" ( https://www.schneier.com/blog/archives/2008/03/the_security_... ) and extrapolate to universe-scale problems; the security mindset is a great place to feed in caution, cynicism, and pessimism, and that's where much of mine goes.

> You have clearly not come to grips with what an unbounded life span actually looks like.

I have, in fact. I understand exactly what you're alluding to when you suggest that there are a finite combination of possible inputs. That's also assuming that the state of the person processing those inputs is the same and has not changed. And that in turn gets into questions about memory and recall and integration of our experiences. (We do not, today, remember literally everything we've ever perceived, and our memories are effectively selective, subjective self-stories of our experiences and perceptions. We should exercise great caution before making modifications to how we handle memory and experiences.) The bigger concern will not be the combinatorial limits on possible inputs; the bigger concern will be the number of combinations of brain configurations; you didn't even make the argument about how in a finite space there may be a limited number of total brain configurations you can have. All of those, however, are limits far far far more distant than the age of the universe.

To get past roughly 120, we need to solve aging and degeneration. To get past thousands of years, we need to solve accidental death, and ultimately move past biology. To get our species safely past millions of years and myriad existential threats, we'll need to distribute ourselves around the universe and otherwise have more redundancy, as well as having much more capability to predict and respond to those existential threats. To get past billions of years, we need a lot more understanding about the fundamental nature of the multiverse. "Number of unique brain configurations" is a problem we may have to deal with even further in the future than that. I don't think it makes sense to avoid solving the first problem because we don't yet know how to solve some of the later ones.

In case it isn't abundantly clear, I am well aware that the probability of personally making it through all of those, given that the first hasn't even happened yet, is not great. There's a difference between hope (which I have in abundance) and naivety (which I avoid). And I make a conscious effort to not fall into the "not thinking about it" trap that most people have about death. But I'm still going to do everything I can to work on the first few problems (in order of priority), and from my perspective, non-zero is always better than zero. As long as I'm alive I'll continue to have hope.

> I'm actually kind of sad that didn't happen this time. I would love for someone to convince me that I'm wrong about this.

I'm hoping that the observations above help in that regard. Beyond that, I hope that time will help. Perhaps when humanity survives climate change you will have more hope, since that seems to be your foremost concern; if it does not, and saying "I told you so" brings you solace, feel free. I wish you the best of success in taking concrete actions to make humanity more likely to survive.

(This will be my last comment on this thread.)