Cynicism evolved into Stoicism, and aspects of Diogenes’ cosmopolitanism found eloquent and refined Roman defenders in Seneca, Cicero and Marcus Aurelius. But it was Hierocles in the second century who provided the most useful way of understanding the basic concept. He described a set of concentric circles. The individual self was at the centre, then came the immediate family, then the extended family, neighbours, nearby towns, your nation, and eventually, on the outer ring, the entire human race. The task before us, Hierocles believed, was to draw these circles ever more tightly towards the centre. We were to move from a state of near-indifference to humanity as a whole, to a state where humankind was a major part of our daily concern.
This target-like image vividly captures the problem for anyone attracted to cosmopolitanism. How can we see ourselves as citizens of the world when we seem so naturally drawn to the centre of Hierocles’ model? Indeed, why would we even want to, since it seems to be going so much against our natural inclinations?
Strangely, he never seems to answer his own question; he merely asserts later that it would be "better for all" if we did. There's a pleasing symmetry to the abstract idea of such a neat, mathematical progression in caring, sure, but I still see no reason to accept the leap of faith required to make "humankind" a sacred concept. "Indifferent with an option to care" seems fair enough to me.