 In Stoic philosophy, cosmopolitanism includes a view of the nature of human beings: human beings are, by virtue of the kind of beings they are, connected. Seneca at times explores fellowship among human beings in terms of family relationships. The family in a conventional sense is a place of ethical learning. Beyond this, there is an idealized and broader familial relation among people and Seneca is open to the idea that one chooses one’s intellectual ancestors independent of biological relationships (Gloyn 2017). The Stoics see human beings as parts of a whole, namely as parts of the cosmos (Vogt 2008, chapter 2). Seneca fully embraces this idea. In On Benefits, a treatise concerned with beneficere as a social practice, but also, more literally, with beneficere understood as ‘doing good,’ Seneca asks in which ways God benefits human beings. His answer aims to explain why, though we do not have the natural weapons other animals have and are in many ways weaker than they are, human beings have the kind of standing in the world he takes them to have, the standing of “masters.” “God has granted two things that make this vulnerable creature the strongest of all: reason and fellowship. […] Fellowship has given him power over all animals […] Remove fellowship and you will destroy the unity of mankind on which our life depends.” (tr. Griffin/Inwood 2011, 4.18.2–3). Seneca’s focus on fellowship is in line with earlier Stoic thought about affiliation (oikeiôsis) between human beings, as well as with the Stoic view that the cosmos is a large animal with us as some of its parts. Ideally, human beings relate as friends to each other. On the orthodox Stoic conception of friendship, only wise and virtuous people are friends (Vogt 2008, 148–160). Seneca endorses this ambitious notion of friendship. In order to be a friend, one must first attain a consistent mindset (Letter 35.2 and 4, cf. Wildberger 2018b). 