I've been thinking a bit more about whether productivity growth rates can permanently outstrip economic growth rates, and what that means if it happens. Comments from me here and here.
I'm starting to wonder if we're not about to bump up against a new kind of Malthusian limit. The old one had increased output leading to birth rates that exceeded food supply, which caused collapse. Is the new version of this improved technology leading to productivity rates that exceed growth rates, causing the number of available jobs to collapse? And does the collapse of jobs presage the collapse of population? Of civilization?
I'm also wondering: what other Malthusian-ish transitions might we have gone through? Clearly there was a point near the Neolithic revolution where we stopped being one of the variables in a predator-prey equation, which seems like a pretty big transition. Are there others? Can we foresee others in the future?