I (think I) understood the GP post, I just have very little tolerance for idiotic and easily falsifiable statements. Therefore, I chose to respond to the first sentence only, and ignore the rest of the post.

My use of that population number was simply that: a refutation of the assertion that the earth has no population limit, as it will be hard to argue that our planet can support 10^9980 humans per square millimeter of land area. A genuine "argumentum ad absurdum", to counter the GP's completely nonsensical opening statement.

I interpreted the opposition to using carrying capacity to mean that it's not helpful from the perspective of a technological species. If we had that many humans, the odds seem high that we would have a way to supplement resources available to use from outside Earth. Carrying capacity is really about an _ecosystem_ and the resources it can provide vs competition with other species. We effectively have no competition, and we can create our own ecosystems, so it's kind of a strawman to apply the wildlife biology concept to our understanding of how human populations will evolve in the future.

Ah, but that would have been an interesting discussion. We could have discussed the merits of carrying capacity with respect to a species that builds its own ecosystem, or whether it makes sense to consider the entire planet a single ecosystem. We could have a meaningful discussion about the various population estimates and what they're based on. Or we could have discussed whether it makes sense to consider ourselves in competition with future generations.

But instead of that, the initial reply:

- refused the basic premise that would have allowed that discussion, by indirectly positing that space on earth is infinite

- followed it up with a very questionable assertion that earth's resources are used "more or less sustainably" (which is already at odds with the previous assertion that resources are infinite, and ignores the many species we've already hunted to extinction)

- added a non-sequitur that we would have run out of resources as hunter-gatherers (again at odds with the initial statement)

- justified the plain refusal of the basic premise with an ad-hominem about bias

- continued on with the apathetic rationalization that nothing can be done anyway

- concluded by reiterating the initial statement without further substantiation

Now, you may argue that my refusal to engage in that discussion is my weakness and it would still have been possible to salvage something positive, however my time is finite and there's better, less taxing discussions to be had.

(/me out, accepting that meta-justification is considered offtopic and will be downmodded).