City living is possible only because a city is not, in fact, a totally anonymous sort of place. While personal knowledge of the vast majority of others with whom the urbanite shares time and space is impossible, categoric knowledge is well within his grasp. The multitudes of strangers forming the urbanite's public milieu may not be personally knowable, but they are most certainly categorically identifiable, and as such, capable of being acted toward. That is, one can live as a stranger in the midst of strangers only because important elements of "strangeness" have been removed.

Lyn H. Lofland, World of Strangers_ Order a…, loc. 151