This page is adapted from my essay Human Nature and Stoic Development on the Stoicism Today blog.
One of the best parts of being a Stoic is the opportunity for lifelong growth and development toward virtue and coherence. Although we may not ever achieve perfection, we can definitely become better and happier than we were before. Let's look at how the ancient Stoic concept oikeisosis can help us progress toward virtue and eudaimonia.
The ancient Stoics believed that nature—our human nature and the world we live in—has provided us with what we need to reach our potential as excellent people. For one thing, we instinctually act in ways that promote our own well-being. As young children our instinct is to seek things that keep us alive and give us comfort: food and the warmth and security of a loving caregiver. But as we grow, our awareness of ourselves changes. We seek out new opportunities, and we have a strong desire to learn, understand, and make sense of the world. We develop our own identities as people, and we become more consciously aware of what is expected of us and who we want to be. We eventually learn that our well-being depends not on material comforts but on how well we fulfill our role as a mature human (Annas, 1993). Some people are confused about the role of a fully mature person; they might think the goal is to become rich or powerful or popular. But Stoics know the only way to find long-lasting inner peace and happiness is to live in agreement with nature, which includes living in agreement with our human nature (Epictetus, Discourses, 3.1).
And what might that nature be? Human nature is complex and multi-faceted, but one of our defining features is our extreme sociability. We always live in groups, and the well-being of the individual depends on the well-being of the group. Our families, communities, cities, and nations in most cases existed long before we were born, and many of them will exist long after we are gone. We are primed and programmed to live with, cooperate with, and take care of others. Not only that, but our very survival as a species depends on are instinctual care for our young. Humans have by far the longest childhood, and require intensive care for the longest time, of any species that we know of. Our instincts as adults prompt us to love and care for our young, and our instincts as children predispose us from a very young age to cooperate with and care for others. We are the social species par excellence.
If we want to reach our potential as humans—thereby becoming happy and fulfilled—we must become excellent at doing what humans do best: living with other people and using our advanced cognitive capacities (and uniquely human self-awareness) to understand the nature of things. The ancient Stoics called this natural progression toward virtue oikeiosis. Oikeiosis literally means something like familiarization, affiliation, or appropriation. It is the process by which you become familiar with your true nature. Your nature as a young child dictated that you depended on adults for survival; your nature as a maturing young person dictated that you started to become independent, acquire responsibility, and develop a mature awareness of yourself and the world. When you become familiar with your nature as a rational and social adult, you will devote yourself to fulfilling that nature, i.e., becoming virtuous. You will grow into the person you are meant to be.
Becoming familiar with our true nature—you might call it fully developing our humanity—requires understanding who we really are in relation to other people. The ancient Stoics spoke of our relationship to others as a part-to-whole relationship: we are individual parts of the same body, we are branches on the same tree, or we are all citizens of the same city (Hadot, 2001; Reydams-Schils, 2005). This communal attitude is foundational to developing an accurate understanding of life and thereby becoming virtuous. If you persist in believing that your own good is separate from the good of other people, you can’t really become virtuous because you hold a very mistaken view of things. But once you understand that your own good is identical to the good of the whole, your perspective (and therefore your opinions, motivations, desires, aversions, and actions) completely shifts. You realize that what benefits those around you also benefits you because you are inextricably linked in human companionship (Epictetus, Discourses, 2.22, 15-19; Seneca, Letters on Ethics, 48.2).
This shift in perspective, from self as isolated entity to self as part of the whole, is social oikeiosis. It requires not just a simple recognition that we are all inextricably linked but a change in our identity or sense of self. It’s quite easy to admit our interdependencies on a superficial level without allowing it to change our attitude or behavior. But we will only properly understand our nature and our role in life when we re-draw the boundaries of “who I am” to include other people.
Another way of putting it is that we are developing a sense of oneness with the people around us. Virtue ethicist and Asian philosophy scholar Philip J. Ivanhoe (2017) has identified oneness as a “relational view about the nature of the self” that achieves “a more expansive conception of the self, a self that is seen as intimately connected with other people, creatures, and things in ways that typically conduce to the greater advantage, well-being, and happiness of all concerned” (p. 3). It seems to me that this expansive conception of the self describes the endpoint of social oikeiosis in Stoicism. Consider one of the most famous ancient explications of social oikeiosis, the concentric circles of Hierocles. His description seems to be a sort of exercise for how we might come to see our individual selves as one part of a larger whole: we first identify with our close family members, then our extended family, then friends and neighbors, then fellow citizens. We expand our notion of self from our narrow personal interests to comprehend everyone around us, eventually including everyone in the world. I think the idea here is to extend our understanding of ourselves as one part of the greater whole, which means expanding our sense of self.
As Ivanhoe points out, oneness has great value to contemporary ethics: it is the basis of several current philosophies of environmental ethics, and some moral psychologists see it as the motivation for altruism (in contrast to the dominant empathy-altruism approach). I think both of these are relevant for modern Stoics. For me personally, thinking about altruism in terms of oneness rather than empathy addresses some of the tensions at the heart of social oikeiosis. This approach suggests that we help other people not because we empathize with their plight but because we feel a sense of oneness with them. As Stoics, we do not actively empathize with others about perceived misfortunes because we have a different idea of what misfortune is. Yet we still care and feel affection for them. Our thoughts and actions are motivated not by emotional reactions but by our rational understanding that we are actually parts of the same whole, which leads to a different kind of altruism.
One further reason for linking Stoic social oikeiosis to the oneness hypothesis is the close association oneness has with “metaphors of natural organic unity, for example about how a healthy person is connected to the various parts of her own well-functioning body” (Ivanhoe, p. 2). These metaphors are a well-known feature of Stoicism. Consider Marcus Aurelius’ memorable comparison of people acting against the common good to limbs severed from a body:
If you have ever seen a severed hand or foot, or a head which has been cut off, lying some distance away from the rest of the body, you will have some idea of what a person makes of himself, as far as he can, when he is unwilling to consent to what comes to pass and cuts himself off from others or when he does something that is against the common interest. By so acting you have, as it were, cast yourself loose from the natural unity; for you were born to be a part of it, and you have cut yourself off. (Meditations, 8.34)
Neo-Confucians, whose ideas inspired Ivanhoe’s oneness hypothesis, express their ideas about oneness in similar terms. For neo-Confucians as well as Stoics, we are so connected and interdependent with the people around us that we form, metaphorically, one body. Here is the neo-Confucian philosopher Cheng Hao explaining why the term “unfeeling” is used to describe both numb body parts and selfish people:
Medical books describe paralysis in the hands or feet as being ‘numb or unfeeling’. This is a perfect way to describe the condition. People with feeling (i.e., benevolent people) regard heaven, earth, and the myriad things as one body; there is nothing that is not a part of themselves. Since they regard all things as themselves, is there anywhere their concern will fail to reach? If things are not part of oneself, naturally they will have no influence upon one. This is like hands or feet being unfeeling. (Cheng Hao, cited in Ivanhoe, pp. 47-48)
Stoicism is certainly not identical to Confucianism, even if both philosophies share a similar outlook on nature, virtue, and development. But I do find it very instructive to think about where the Confucians headed with their corporal metaphors, and where we as modern Stoics might end up. Although they “saw a deep identity between themselves and the world” (Ivanhoe, p. 146),
Neo-Confucians don’t lose the self in or wholly merge the self with the world; they maintain the hierarchy of concern characteristic of Confucians in every age…So while we are one with every aspect of the universe, there is a hierarchy of concern, a core and periphery to the universal self, modeled on the natural hierarchy among the parts of our physical bodies. (Ivanhoe, pp. 49, 50)
The ancient Confucians were challenged by a rival philosophical school, the Mohists—and neo-Confucians were challenged by Buddhist thought—to clarify and defend their position on the privilege of family relationships. While Mohists argued for complete impartiality toward all people, Confucians traditionally maintained that we owe our family members and close associates more than we owe to more distant associates or strangers. Likewise, strict forms of Buddhism require giving up all attachments, including to family and friends, but:
While several neo-Confucians argued that we are one body with heaven, earth, and the myriad things, they were eager to emphasize that we care to different degrees and in different ways for the various parts of our bodies. While one's heart, lungs, toes, skin, fingernails, and hair all are equally parts of the unity that is one's body and one cares for them all, one does not care for them equally or in the same way. (Ivanhoe, p. 47)
While oneness does require us to expand our sense of self to care for everyone in the world, that does not mean we must do for strangers exactly as we would do for our parents or children. Perhaps there are a few saints and Cynics in the world who are able to give up all their social attachments and truly live for all of humanity. But this is not an attainable or desirable goal for most people. For most of us, the goal of social oikeiosis is not impartiality but rather “an expanded sense of self that embraces the other and brings it, to varying degrees, within one's conception of oneself” (Ivanhoe, p. 71).
It’s a daunting task, but the ancient Stoics seemed to believe we are equipped for it by nature. People often get distracted from their true nature by “the persuasiveness of things” and “the teaching of their associates,” according to Chrysippus (Graver, 2007, p. 154-158). Unfortunately, we have even more of those distractions today than ever before. But for better or worse, human nature hasn’t changed in the past 2,000 years, and I think we are still naturally equipped to grow toward virtue. Through observation, study, reflection, attention, and constant practice, we can learn to see the world (and our place in it) clearly and accurately. And by pushing ourselves to align our well-being with the well-being of all other humans, we can develop an expansive sense of self that (eventually) encompasses everyone. In so doing, we will become familiarized to other people and to our own nature, eventually resulting in the long-lasting happiness of eudaimonia. As Ivanhoe (p. 102) puts it:
When one develops one's natural needs, desires, inclinations, and capacities in ways that harmonize and unify one's inner psychological states and fits these into a grand natural order that facilitates successful action in the world, and when one reaches the point where one regularly and spontaneously achieves these dual aims, one feels that one is one's element, has found one's home, and is performing one's proper role in the world. Such action generates a special feeling of joy or happiness not only for those who behave this way but also for those who observe such behavior.
 For a very interesting theory on how our social nature shapes our other advanced cognitive abilities (language, abstract mental representations, cooperative planning, etc.), I highly recommend Michael Tomasello’s Becoming Human: A Theory of Ontogeny (2019).
 Just to be clear, this recognition of unity, or the process of social oikeiosis more generally, does not change a Stoic’s view of what is ‘up to me’ and what is ‘not up to me.’ Even a person’s own body is considered external and outside the sphere of choice, and other people remain firmly in this category. Social oikeiosis does not remove a person’s autonomy or moral responsibility.
 The empathy-altruism approach suggests that people are motivated to act kindly toward others based on feelings of empathy for the other person’s condition.
 See Ivanhoe, pp. 70 and 89-93, for more on oneness and altruism.
 Neo-Confucianism was a flowering of Confucian thought in China from around the 11th through 16th centuries.
Annas, J. (1993). The Morality of Happiness. Oxford University Press: Oxford.
Epictetus. (2014). Discourses, Fragments, Handbook (Robin Hard, Transl.). Oxford University Press: Oxford.
Graver, M. (2007). Stoicism and Emotion. University of Chicago Press: Chicago.
Hadot, P. (2001). The Inner Citadel: The Meditations of Marcus Aurelius (Michael Chase, Transl.). Harvard University Press: Cambridge.
Ivanhoe, P. J. (2017). Oneness: East Asian Conceptions of Virtue, Happiness, and How We Are All Connected. Oxford University Press: New York.
Reydams-Schils, G. (2005). The Roman Stoics: Self, Responsibility, and Affection. University of Chicago Press: Chicago.
Lucius Annaeus Seneca. (2017). Letters on Ethics (Margaret Graver and A.A. Long, Transl.). University of Chicago Press: Chicago.
Tomasello, M. (2019). Becoming Human: A Theory of Ontogeny. Harvard University Press: Cambridge.