There is deeper sense of the cosmopolitan and one rooted in the Stoic philosophers. It is this Stoic sense of the cosmopolitan that I want to discuss. Much has been written of Stoic cosmopolitanism. The genesis of the term is widely attributed to the Cynic, Diogenese (the polar opposite of what we would understand in the popular mind as the cosmopolitan). When asked where he was from, Diogenes famously replied, “I am a citizen of the world (kosmopolites)”. There has been a wealth of commentary on what Diogenese meant by this phrase. Philosophers and historians agree that the Stoics inherited and developed the idea of the Cosmopolitan directly from the Cynics. There is excellent analysis by Martha Nussbaum and John Sellars on this very question. Sellars' article, in particular, is very good if you want a comprehensive history of the idea of the cosmopolitan in the context of Zeno’s Republic. But I want to offer my own take on what Diogenese may have meant when he said that he is a citizen of the cosmos.
One clear, fundamental doctrine of Stoic philosophy is that the cosmos is ordered and filled with Divine light and intelligibility. This is in contrast to the idea of chaos being a characteristic of the universal order. The Greeks often juxtaposed chaos and cosmos in their narratives and this interplay can also be seen in the first chapter of Genesis as well. Because nature (or the cosmos) had such order and intelligibility, we should strive to live in accordance with its rhythms argued the Cynics. In some ways, we also possessed the light of the cosmos in our consciousness suggested the later Stoics. The mode of this light or wisdom in human consciousness was debated - but what wasn’t debated was the fundamental nature of the cosmos as order, intelligibility and light.
Our lives need to be ordered to the cosmos and not social conventions which actually thwart and frustrate that ability. For this reason, the Cynics eschewed social conventions and the Stoics also argued that the acquisition of wealth or external status would not lead to a fulfilling life and would not make one a philosopher (lover of wisdom). One had to give themselves over to wisdom which in some way had a divine character expressed and shaped by the cosmos. This does not mean that the Stoics believed that wisdom was a revelation of the Divine order (as the Christians would argue). Instead, humans resemble the divine to the extent that they can order their mind as the cosmos orders nature.
But, in order to do so, one had to first discipline the mind and the appetites through struggle. The image of the one struggling or the wrestler is invoked by some of the Stoics. It is this psychological struggle that enables one to break free of provincial attachments and social conventions and manifest the divine wisdom and spark (or fire) of human consciousness.
This brings me to what I think Diogenese meant by being a citizen of the world (cosmos). He was not necessarily referring to political identification with the planet, or even the human species (pace Nussbaum). I think Diogenese meant that his identification was with the transcendent reality of the cosmos. It was this reality he belonged to and lived out of. Whether others shared in that collectivity was not something the Stoics were concerned with. Their politics was in that sense anarchic; they desired neither to rule over or be ruled by anyone. Theirs was a collectivity and “citizenship” based on style of thinking or temperament or philosophical outlook. In that regard Sellars’ analysis of Zeno’s republic is on point in that there is a kind of community or group of people who are “citizens of the world”. But this citizenship cannot be an affectation but must instead be an experiential mode of being – almost like secular monks - but even freer than monks who are often bound by a monastic rule. Nonetheless, there is a rule that the monastic/philosopher/Stoic adheres to and it is the rule of the cosmos as expressed by the sages. But it is different than a vowed life of monasticism although it is a committed lifestyle (and yes an ascetic one at that!)
There is a resurgence of popularity of the Stoics and this cosmic dimension of their philosophy is not something that can be denied as anachronistic and bound in pre-Modern notions. Instead, the idea of the cosmos as, in some sense Divine, is part of the foundation of their ethics and physics. Certainly, the mathematical and scientific representation of the physics can change - and so can the mode or presentation of the conception of cosmos. But one thing is clear – the cosmos is well ordered, logical, and full of life (if not Life itself). Living in accordance with this cosmos is the very foundation of what it is to be a Stoic. And it was this that I think Diogenese was driving at and which animates my philosophy of life as well.