I think there are pros and cons. You mention some of the pros. Right now I think the ideal population growth would be slightly below replacement level for a whi

I think there are pros and cons. You mention some of the pros. Right now I think the ideal population growth would be slightly below replacement level for a while, and then replacement level once we hit a population that seems to "work." You can't ignore the social problems created by shrinking populations though. A major one is monopolization of high positions in business and politics by an increasingly elderly class that is stuck in an obsolete way of thinking. In America this has given birth to the quip "ok, boomer." I don't like sounding age-ist, but it does seem as if most people stop updating their understanding of the world at some point in their 40s. I don't think it's that older people can't learn. My grandfather taught himself computer programming, called BBSes (at 300 baud!), learned digital/TTL electronics, and learned all kinds of other new stuff in his 60s. It's just that most people don't do this. I think it might be an ego thing. People decide they know it all at some point and stop learning or changing their opinions. It could also have less to do with age than with age plus status. High status people rarely seem to make drastic revisions to their world view because their brain stem is telling them everything they're doing is working. (At least this is the mechanism I suspect exists. It would have survival value to some extent.) So you get entrenched older managerial and political classes that double, triple, and quadruple down on failing policies because the failure has not affected them yet. A second problem is that virtually every society on Earth today uses growth to paper over a range of systemic failings. Instead of dealing with inequality, we use growth. Instead of getting rid of moribund industries we use growth to make new ones while keeping the old stuff around. Growth really does avoid the need to confront a lot of very messy problems. Recent political history has not inspired confidence in me that we can confront these problems any more rationally than people in the past.