> We can easily have a trillion humans living in abundance in our solar system. No, we can't. The more educated people get, the lower their fertility rate. We

> We can easily have a trillion humans living in abundance in our solar system. No, we can't. The more educated people get, the lower their fertility rate. Western countries are well below replacement fertility now, with the likes of the US and Canada being topped up by immigrants. The reason is thought to be simple. Parents have a limit to the amount of time and money they want to invest in their children, and much of the investment is zero sum (getting your child into "better" schools, enrichment activities, etc.). Unless you can describe a realistic way that the rest of the solar system can be settled by people with no more than 6 years of schooling, or you are proposing an army of test-tube clones, a trillion people is simply impossible.