If you don't believe in borders why do you lock your front door at night?

Your House has a selectively permeable border – you front door. The idea of selectively permeable borders works at ALL scales. https://t.co/HlUQXSLAWF

— GuruAnaerobic (@GuruAnaerobic) August 29, 2019

This isn’t a perfect analogy, but agreed. Countries aren’t the same as homes, but in many important senses they are. I’m wary of analogies that conceal more than they reveal but in this case it works. Open borders is an idea that can only function non-destructively with roughly similar cultures, level of development and social welfare systems. Otherwise, a lot of that will get destroyed.