> If I find a way to cut hair twice as fast, that's GDP growth.
Only it makes people get more haircuts or their is a labor shortage you get a second job.
> If somebody makes a CPU that's faster and consumes less energy, that's GDP growth
Only if it inspires more CPU purchase or usage that costs more energy use overall.
There are things that are productive that aren't jobs. You having more time to read HN probably has some productive value, because it teaches you things. It doesn't directly translate to an increase in GDP immediately, but it does do that over time. The hair dresser might end up learning new things during that free time, which would eventually lead to an increase in GDP.
>Only if it inspires more CPU purchase or usage that costs more energy use overall.
Or we get to use the same amount of energy to do more computation. There's a lot of things that can eat up more computation.
GDP growth doesn't mean using more resources. If I find a way to cut hair twice as fast, that's GDP growth. If somebody makes a CPU that's faster and consumes less energy, that's GDP growth. If someone finds a way to distribute parcels more efficiently via a better heuristic for the travelling salesman problem, that's GDP growth.
GDP growth is only bounded if there's a hard limit on the amount of useful ideas people can have, and I think even if such a limit exists, we're extremely far away from reaching it.