More random musings, mostly to try to get my own head straight on some questions. (I should steal Robert Waldmann's idea of calling them "stochastic thoughts".) And probably not very original. But sometimes it's easier to try to reinvent the wheel than walk to the library and read all the books on "wheels"; and experiential learning is a good thing anyway, they tell me.
"AK": Ideas (about new technology) are neat, because a good idea can double output across all scales of the other inputs.
"Solow": But the trouble with ideas is that you have to learn them (investment), and that's time you can't spend working at producing consumption goods. And then you die, so that investment is lost (depreciation). So there's decreasing returns to ideas at the macro level, because more ideas to learn means less time producing goods using those ideas.
"Smith": But we have a division of labour, so not everyone has to learn everything. And the division of labour is only limited by the extent of the market.
"Schumpeter": The really good ideas are new ideas that destroy old ideas, so you don't have to learn the old ideas and can torch the ancient libraries.