It's not that difficult for anyone to believe that as human beings, we have rights that supersede any constitution or government created by man. It can delve into metaphysical debate, but one that concludes that we have human rights simply by virtue of being human.
It is not that abstract , we either have an objective standard or rely on a 'Nash Equilibrium' like OPEC does in setting its price floor. Of course, 'the floor' is always undercut as producers 'cheat' and undersell each other, even though all participants will claim 'to follow the program'.
More simply, we would be 'Relying on the kindness of strangers'.
There is no pre- ordained system of government or set of laws on how people should treat each other.