This is not a contradiction as these are multiple variables. The most important variable is the size of population able to participate in knowledge production.

This is not a contradiction as these are multiple variables. The most important variable is the size of population able to participate in knowledge production. Naturally higher the population size, higher the size of population able to participate in knowledge production. This creates a positive feedback loop on the population growth. Downside of this is that every gain that would allow better living is eaten up by the population growth (there is actually name for this - Malthusian trap). Downside of this is that the size of knowledge producing population stays relatively constant in relation to the total population size. There is another feedback loop, three actually. If households restrain the number of offspring in return of better education of the offspring then three things happen. First the size of knowledge producing population starts to grow independent of total population growth, total population growth will stagnate or decrease and amount of personal wealth will increase (surplus of resource growth is divided among fewer people). This is also why Western world is rich, large parts of Asia is getting rich and Africa and India are staying poor. Naturally there is a huge downside in the negative feedback loop on the population growth as eventually it will start hurting the total amount of knowledge production. It would be better if these two feedback loops would balance each other out.