Kerry Howley has a fascinating piece in Reason on fertility panics. Let me make a few points I consider obvious: entitlements are not a reason to have more children, natalist panics often have an unpleasant flavor of racism to them, and ever-increasing populations are neither sustainable nor desireable. The transition we are currently facing will be moderately difficult, but as I wrote for The Atlantic, it will not be a disaster, and at the end of the transition, we will still be a wealthy society with a lot to live for.
That said, I think Will Wilkinson goes too far when he says
The way I see it, those obsessed with fertility are people who think the culture they desire cannot possibly win the argument against competing cultures. So, they conclude, it’s down to brute baby-making force: the culture that wins the fertility war wins the culture war. In contrast, I think liberal market culture has such immense, salient rewards (wealth, longevity, happiness, etc.) that it is not only possible to win the argument, but that we are in fact winning it. Of course, part of the winning is dynamist cultural synthesis. So if you’ve got a conservative, zoological view of cultural preservation which fixes on the importance of high-fidelity copying of inessential aspects of a culture’s history (costumes, holidays, rites, cuisine, skin colors etc.), you’re going to have a hard time of it. But if you care about the essential core of liberal modernity, you should be delighted with how things are going. You’ll eat your szechuan taco pizza and you’ll love it.
Cultures don't have "arguments". The most important core beliefs most people have are transmitted not through dialogue, but through inheritance. It is extremely likely that you share the political views of your parents, their religious affiliation, and at a less obvious level, their beliefs about things like what constitutes stealing and lawbreaking, and what are justified evasions of petty laws. My mother is the one who would make us turn around and drive twenty miles back to the store if it turned out we'd forgotten to pay for things, and I now have the same attitude.
The overwhelming evidence is that when it comes to culture, numbers trump ideas. in the successive invasions of England, for example, the locals always won unless they were wiped out; the conquerors assimilated. Or look at America. More people here claim descent from the Irish than the English; numerically, Irish Americans are the largest single-country ethnic group. Yet our culture is much more heavily derived from English Prostentantism than from Irish Catholicism. That's because the earlier waves of assimilated immigrants had adopted the fundamentally British culture of America, and outnumbering the Irish, forced them to assimilate. Successive waves of immigrants have each left their cultural mark, changing (I devoutly believe) us for the better, and also to something that cannot be called British. But the dominant strain remains English. Cultures that "win" the argument in territory outside their own do so by killing, swamping, or removing the previous inhabitants.
Food is awesome, but it is culturally trivial. A little while ago, I said that I thought that liberals underestimated the extent to which the welfare state is spending down cultural capital accumulated in an era before safety nets. Similarly, I think libertarians tend to vastly underestimate the extent to which liberalism and free markets are sustained not by proclaimed belief or legal institutions, but by unobserved cultural norms that are transmitted slowly, if at all. Mexico can see all the things that are better about the US, none of which are particularly difficult to reproduce at the institutional level, but enforcement depends on things like a visceral indignant reaction to policemen who take bribes, rather than an attempt to work the system by developing friends in the police force. Tyler Cowen now believes that returning immigrants are shifting those norms, but we're talking about a process of decades, if not centuries. I deeply enjoy having access to world music, world art, world food--but none of them improves my life as much as living in a country with robust cultural support for individual freedom, democracy, capitalism, and liberalism.