graydon: why exactly do you call the proposition that it makes the more-rapidly-reproducing people reproduce more if we go away an absurdity? it seems blindingly obviously true to me. unless, of course, you think that if in 20 years Canada (just to pick an example) becomes deserted due to the current generation not reproducing, it'll stay deserted. now that is indeed absurd.

the point being that humans are now the dominant species, and so they will naturally fill the available space as long as they fill comfortable. so if you make room, others will take the room. you need to convince more people that lots of room is desirable. until you do that, it doesn't matter at all whether or not you, personally, reproduce.