The stranger-known-other distinction is unstable yet practically meaningful.

Evidence

Despite such analytic nit-picking, the distinction between strangers and personally-known others remains, for all practical purposes, a meaningful one. The fact that the distinction is unstable, that strangers can be transformed instantly into personally-known others is one of the fascinating dynamics of social life-a dynamic that we shall have occasion to consider in more detail in Part 2. For now, however, the more static view, which clearly demarcates the one from the other, will be most serviceable. — Lyn H. Lofland, World of Strangers_ Order and Action in…, 115

Categorization

• XREF: Practical typification of strangers parallels Lofland’s broader category-of-the-categoric theme and Simmel’s mental types. — connects to: Beauvoir’s threefold ambiguity defines the human as immanent-transcendent, free-yet-unmade, and conflicted-with-yet-requiring the Other. — Christine Daigle, Jacob Golomb (eds.), Beauvoir and Sartre: The Riddle of…, 112