I suspect everybody is together in hoping that when cultures mix, good cultural practices that support human flourishing win out over bad ones. The question is what follows if this doesn't happen, or doesn't happen in any predictable way. This seems to me the kernel of disagreement between you and your interlocutors on a host of issues (demography, immigration, etc.), and a large part of the reason the two sides seem to be talking past each other.
So two questions I'd be very eager to get your response to:
1) First a (crude) hypothetical. Let us *stipulate* for a moment that when cultures mingle, the values that predominate are not those that support human flourishing, but rather are the ones held by the largest number of people. Under this stipulation, would your attitude towards baby-bust concerns and immigration policy change, and if so, how?
2) What evidence would lead you to believe that this stipulation is more or less correct? By way of example, what evidence would make you worry that aspects of the US culture that you believe promote human flourishing (gender equality, religious toleration, respect for property rights) might be adversely effected by immigration of people from cultures that do not share these traditions?
