We can find a starting point for this discussion in the familiar sociological observation that in modern social life many people, much of the time, interact with others who are strangers to them. As Simmel pointed out, the meaning of the term “stranger” changes with the coming of modernity. In pre-modern cultures, where the local community always remains the basis of wider social organisation, the “stranger” refers to a “whole person”—someone who comes from the outside and who is potentially suspect. There may be many respects in which a person moving into a small community from elsewhere fails to receive the trust of the insiders, even perhaps after having lived in that community for many years. In modern societies, by contrast, we do not characteristically interact with strangers as “whole people” in the same way. Particularly in many urban settings, we interact more or less continuously with others whom we either do not know well or have never met before—but this interaction takes the form of relatively fleeting contacts.

XREF: Connects to Simmel's sociology of the stranger and the character of urban anonymity, resonating with literature on the modern metropolis and urban alienation.

Anthony Giddens, The Consequences of Moderni…, loc. 197