A common approach rebutting open borders is to argue that the costs of liberal immigration policies outweigh the benefits to humanity. I’ve never actually seen this belief explicitly expressed in a universalist manner — the argument is usually focused on how immigration will destroy the wealthy economies and liberal societies of the world. But I think this argument is a serious one, and I give it serious credit.

This does not always seem to be the case; one may sometimes feel that open borders advocates are a tad glib in dismissing concerns that open borders might “kill the goose that lays the golden egg.” To be blunt, this is because there is no empirical evidence supporting this claim.

If we look at the past, the same concerns people have today about Latin American, African, Arab, or South Asian immigrants used to be directed at East Asian, Southern European, and Eastern European immigrants. The same people today who vocally embrace “high-IQ” or “high-skilled” immigration of Jews, Europeans, and East Asians, would find that these very same groups of people used to be the “low-IQ” and “low-skilled” immigrants who were not so long ago literally treated as vermin in their countries. Fears that the unintelligent, criminal, brute Catholic Irishman or Italian, or the conniving and unintelligent Jew, might ruin civilisation turned out to be unfounded.

If current levels of immigration were a harbinger of impending doom, it would be quite easy to prove this. It’s fairly easy to point to anecdotes — but surely laying one’s finger on the data would be easy too. You’d show skyrocketing rates of crime, environmental collapse, or economic depression and clearly link them to immigration in some fashion. Yet no credible academic study I’m aware of has been able to do this. Restrictionist memes blame immigrants for the impending collapse of civilisation in Western Europe or California, yet the actual academic backing for these views is hard to find.

It’s surely not because academics are afraid of voicing politically incorrect views. A vast conspiracy of intellectuals to open the borders and silence such a devastating finding would be quite difficult to keep secret. And yes, one can find credible empiricists skeptical of immigration. Yet the most famous academics whose works actually credibly show negative impacts from immigration — George Borjas and Robert Putnam — both do nothing but disappoint.

Borjas finds that immigration to the US slightly reduces the incomes of the poorest American citizens — something that could easily be addressed through keyhole solutions which redistribute some of the gains from migration to poor natives. Putnam finds that social diversity reduces a theoretical measure of “social capital“, but even his credible result has been challenging for other researchers to replicate. If this is the worst we have to fear from immigration, I say bring it on.

The truth is, we don’t know very well what a world with open borders would look like. We know it would double world GDP — studies of the effects of  greater immigration on world GDP are remarkably consistent in predicting a massive boost to world income, regardless of their theoretical specifications or empirical approach. But given that far too few academics are seriously studying the impacts of immigration in an empirical fashion, we don’t have enough data to say with certainty that much of what we currently know to be true about immigration would still hold true in a world with massively looser immigration policies than today’s. We couldn’t guarantee that immigration would continue to be more or less neutral with respect to native incomes, and have a neutral to positive impact on crime.

But the precautionary principle only militates against immediate open borders. There is nothing stopping us from experimenting with a little more immigration. As the world’s population grows, as humanity grows richer, it makes absolutely no sense that our visa policies are held hostage by the immigration quotas of decades ago.

Open borders advocates actually aren’t asking for much. We simply believe in making the presumption that all who seek to move may do so — a presumption that can be overriden by a clear and pressing need, such as, say, the actual risk that your civilisation might collapse if you don’t shoot the next prospective immigrant in the face. As philosopher Phillip Cole puts it:

In effect all I’m proposing is that immigration should be brought under the same international legal framework as emigration. Immigration controls would become the exception rather than the rule, and would need to meet stringent tests in terms of evidence of national catastrophe that threatens the life of the nation, and so would be subject to international standards of fairness and legality.

I and I think other open borders advocates take concerns about global catastrophe quite seriously. Given that we typically come from universalist and sometimes even nationalist or citizenist moral starting points, we have every reason to be concerned that open borders might mean the end of the world as we know it, in a horrible way. But search the evidence, and you find no actual reason to be concerned about current immigration levels, and every reason to believe that open borders would immensely benefit us all. Even if you don’t find the evidence sufficiently compelling to tear down the border checkpoints right this moment, it’s compelling enough to demand more thorough research and compelling enough to demand experimentation with ever more liberal immigration policies.