"To conclude, then, we must in a general theory take as our unit a social action, that is, an action involving a large proportion or the entire domain of society. At the most basic axiomatic level, individual actions play little role. The need for a system of public values then becomes evident; actions being collective or interpersonal in nature, so must the choice among them. A public or social value system is essentially a logical necessity."
January 1, 1970
https://en.wikiquote.org/wiki/Kenneth_Arrow