οἰκείωσις and 'la sociabilité naturelle des hommes'

The term, οἰκείωσις [oikeiosis], is a core concept of Stoic ethics.  It is also a foundation of Grotius's natural law theory.  Some of my current writing is now focused on revisiting this concept.  

Let me try to work out my understanding of οἰκείωσις. Why is it important for Grotius's theory of natural law?  Very simply:  For Grotius, natural law derives from this thing the Stoics called οἰκείωσις.

Grotius, De Jure Belli ac Pacis (Amsterdam, 1720): p. v [Proleg. §6]

But this is a notoriously difficult term to translate. Barbeyrac, in his French translation, understood the difficulty and rendered this passage as follows: Grotius, Le Droit de la Guerre, ed. Barbeyrac (Amsterdam, 1729) p. 7  Barbeyrac was careful in handling this passage. He characterizes οἰκείωσις as 'a word derived from the feelings that family members have for one another.' And this is a pretty good explanation of the Stoic term, as it captures how much the concept is connected to the οἶκος - the domestic household or family which is the basis of οἰκονομία - 'oeconomia' the science of domestic management. Fundamentally, οἰκείωσις is about that family-feeling or fellow-feeling, the mutual affinity, the connectedness, the familiarity that family members share towards each other. But there is a famous footnote that Barbeyrac adds to this passage, where he renders οἰκείωσις as:

'La sociabilité naturelle des hommes' - which is later translated into early English translations of Grotius as 'the natural sociability of humans.' 

So much of the modern scholarship now on Grotius and the modern natural law school focus on 'natural sociability.'  But in my view, it conveys a somewhat different idea - perhaps intentionally.  Barbeyrac, after all, was writing during the Enlightenment when the aspiration for a 'human science' focused on the various passions, including our apparent sociability.  And this also has become a convenient way to contrast Grotius with the self-preservation motivating Hobbes's theory.

But I favor Barbeyrac's original instinct.  Seeing how fundamental οἰκείωσις is to Grotius's whole natural law jurisprudence, we should set aside the Enlightenment-inspired understanding of 'sociability' as a kind of science, and instead, reflect on what Grotius (as well as the Stoics) see in family life.  

Two promising points that are now the center of my investigation:

One is the linguistic relationship between οἰκείωσις and οἰκεῖος [oikeios]. The latter is an adjective, conveying a sense of belonging to some family or household, particularly important for inheritance, where it becomes legally important to show that an heir belongs to a household.  If οἰκεῖος is the adjective, we can think of οἰκείωσις as the quality of belongingness, familiarity, intimacy.

Why would this be useful for Grotius? His point is to show that there is a οἰκείωσις naturally among humans.  Not only do humans form a 'societas humani generis' as Cicero sometimes claims, we all belong, by nature, to a human family and share family feelings towards each other, certain duties towards each, a desire to help each other, show kindness to each other.  This is the beginning of peace that Grotius desires and that Cicero already identified (see e.g De Finibus).

The other point that drives my research is Grotius's theology.  In the Greek New Testament, the term, οἰκεῖος, appears in several revealing moments, explaining how we all 'belong to God's family' or 'the household of God.'   Here are several examples:

Grotius, Annotationes in Nov.Test. Ephesians 2:19

Grotius, Annotationes in Nov.Test. Galatians 6:10

I think the phrase, 'natural sociability,' has been another obstacle for a proper understanding of Grotius's natural law theory.  And I would advise scholars to stop using it.  

But the biggest problem as I see it is that Grotius's theology is completely ignored in modern scholarship - especially among scholars who are trying to turn Grotius into some kind of secular liberal.  Even more so than the Stoic roots, Grotius's Biblical scholarship is the most important guide to understanding the foundation to his entire natural law theory - that is, the point that everybody belongs to God's household through Christ.  The duties we owe to each other follows from the fact that we are brothers and sisters in Christ.