So in the whole anti-natalism/pro-natalism conversation (which I'm mostly agnostic/undecided on, currently), my friend who is a pro-natalist, argued that the success/stability of our world economy is dependent on procreating more children each year than the previous year, so that we not only replace the numbers of the people who existed from the previous generation (and some, to account for the statistical likelihood that many won't have children or will be sterile or die young etc), but also ensure that the population keeps growing in order to produce more and more human labor to "pay back the debts" of previous generations, because all money is borrowed from somewhere else... this is all very murky to me and I wish someone could explain it better.
She is also of the view that this will inevitably lead to population collapse/societal/civilisation collapse because we live on a finite Earth with finite resources that can't keep sustaining more humans & human consumption (and are nearing critical environmental crises), but that there isn't any other option than to keep producing more children because a declining population wouldn't be able to support itself economically either. Basically the idea seems to be that economically & societally we're on a collision course for self-destruction but the only thing we can do is keep going and making increasingly more of ourselves to keep it running (however that as individuals, we should be plant-based & minimalist to reduce our impact to the environment, non-human animals and humans for as long as possible). And she is worried about the fact that fertility rates are falling & slated to reach a population peak followed by a decline in the relatively near future.
As I said I'm not sure how I feel about this view but at first glance I think that the effect of having fewer children in providing relief upon the environment and helping safeguard our future is more important than preserving the economy because destroying the actual planet and life itself seems worse than economic downturns/collapses, but I really don't know enough about economics to say for certain.
Statistically 2.1 births/woman is required to replace the current population.
As for the economic argument, your friend is somewhat correct, except that economies don't just grow or shrink based on population (it is a major driver). There are too many factors at play to make such a statement.
The finite earth argument is interesting, whilst we are the biggest danger to the biosphere in the short run, we are also the biggest hope. In the long run the biosphere will sort itself out after we are out of the picture.
Taking this argument a little further, we may be the only hope for an intelligent civilisation from this planet. We have taken all of the easy energy resources; which take millions of years to regenerate; so any intelligent civilisation that follows after us will not have the luxury of cheap abundant energy.
So we either sort our shit out, become space faring, and move on with the next phase of the human experiment, or the likelihood of intelligence leaving earth is quite low.
We could, reduce ourselves content to "save" the earth and exist here in perpetuity, but I don't really see that happening. There will always be those that dream and strive, if humans still exist in 10,000 years they will be spacefaring.