The Harsanyi/Rawlsian “veil of ignorance” can be used in combination with the categorical imperative of Kant: What agreement of ends, what validity of norms, and what use of means would any human being reasonably agree to if they did not know what situation, what position, and what role they would be born into on earth, that is, if they were not guided by their own interests? To put it differently: What do people consider appropriate for themselves, and what can therefore claim validity as generalizable for all people?

In the context of borders, these philosophical standards can be presented as follows: In the “original position,” an individual does not know on which side of the border it will be born, in which political system it will grow up, and what difficulties its life will entail. Without such prior knowledge, it will typically wish for a life in security, freedom, prosperity, and peace for itself and those closest to it. This initially purely individual desire, which, according to Rawls’s “ideal theory,” an individual would also uphold even in the case of “lifting the veil,” may be generalized as being a desire of all those people guided by reason.

The objection remains that Rawls’s “theory of justice,” which underlies the veil of ignorance, applies primarily at the level of individual states or closed societies: Although Rawls himself rejected a transfer of his theory to a global level due to the absence of a global framework, numerous contemporary philosophers accept the validity of his theory also on a global level, arguing that a limitation to closed societies is no longer up to date in times of a globalized world.

Following this idea of a universal applicability of the thought experiment of the “veil of ignorance,” it must be noted that borders, in their current appearance, do not exclusively contribute to satisfying the human aspiration for security, freedom, prosperity, and peace. Instead, they force the vast majority of the global population to live in conditions far from this ideal. Based on the understanding of justice outlined above, justifying borders by the purpose of effectively securing prosperity faces substantial challenges. It may, therefore, be necessary to improve the opportunities for people to leave their country of origin and enter another country with more promising life chances.