Why a large human population is good

This was Paul Romer in 2001, applying his distinction between objects and ideas:

If everything were just objects, like trees, then more people means there's less wood per person. But if somebody discovers an idea, everybody gets to use it, so the more people you have who are potentially looking for ideas, the better off we're all going to be. And each time we made a little improvement in technology, we could support a slightly larger population, and that led to more people who could go out and discover some new technology.