If declining population growth is a cause of stagnation, how do we solve it?
Solve it? I see declining population growth as God’s greatest gift upon humanity of the century—more so than Penicillin and Haber process combined—that at least temporarily staved off a return to a Malthusian world. But if you insist on solving the issue, well, Moloch will take care of that soon enough.
With continued progress, we are not limited by land area and fossil fuels. We are not even limited to planet Earth. We are limited only by the speed of light, the Hubble expansion constant, and the heat death of the universe. If we hit those limits, I’d say humanity had a pretty good run.
That’s… not very reassuring? Anything beyond the solar system is completely irrelevant as far as exponential growth is concerned since travel time is so long expanding to the stars won’t relieve local population pressure at all. You seem to be analyzing everything in the exponential context except when it comes to resource limits.
This reminds me that this topic comes up periodically, where I think there are fair amount of differing assumptions or frames between people assuming “overpopulation obviously bad?” and “underpopulation obviously bad?”, and I don’t know of a good writeup that walks through all the considerations, and I’d like someone to write one.