Robin Hanson on Long-term Growth

Arnold, I hope you'll forgive me for posting this both on Overcoming Bias and here, but I'd be very interested to hear thoughts on these questions from both of you.

Robin:

Your augment/replace waterline model is, IMHO, profound. To bring it down to our current situation:

Have we reached that plateau? Perhaps sometime in the 70s, give or take?

Is it related to the limits of (aggregate) human cognitive capacity? IOW, since 50% of people have an IQ below 100, and “valuable” knowledge-worker tasks are requiring ever-greater cognitive skills, can the ameliorating effects of education continue to maintain the augment/replace ratio?

Since machines currently are not people, but are owned by people (so the machines’ earnings go to the owners), could this explain the increasing wealth and income disparities (labor vs. capital, wages versus rents) in recent decades?

Re: your much-less-than-satisfying answer to the question about Germany’s success (highly industrialized, but with major social programs): is it possible that in order to maintain demand for ever-more-efficient productive capacity, government redistribution is a necessity? No–not at 1,000 times some imagined level, but somehow relative to per-capita shares of production?

Given that individual utility functions (as measured by “happiness”) seem to flat-line at about $15K in annual income in developing countries, about $60K in the U.S. (yes, iffy stuff, but the threshold/flat-line seems likely at some level), can the demand from a small cadre of owners–who don’t “value” most goods very highly–provide the demand necessary to keep the economic log rolling?

Could the absence of this widespread demand–making it difficult for capital to find productive investments that pay a good return–explain the massive increase in “casino investing” over recent decades? A desperate search for returns in a world where demand does not reward valuable production?

IOW, could the Luddites (finally) be right? Even a stopped clock…

Robin Hanson is plainly utopian accumulating positive conventional wisdoms in qualifying the use of future technology for long-term growth. He neglects all negative feedback: i.e. Damocles’ absolute nuclear sword, held by a thread, now hanging over our heads.

The problem I have with Hanson's model is that he doesn't seem to think there is a lower bound to how quickly the economy can double. At some point it's going to be impossible for human society to physically implement and adapt to technology any faster.