Georg Simmel's famous and influential essay "The Stranger" introduces the sociological category of the stranger and his social function within groups. According to Simmel's argument the stranger is dissimilar from the wanderer which comes and goes but is rather just one who always has that potential since he doesn't truly and fully belong. The stranger for Simmel is one which is within the bounds of society but wasn't so from the beginning not are there any guarantees that he will to continue to be so. In Margret Mary Wood's words "the stranger is perceived as being in the group but not of the group".
Simmel describes the stranger as one which unites distance and closeness. The stranger's distance renders anything close distant while his closeness renders everything distant close. He is an insider and an outsider at one and the same time and that what makes him so important.
Simmel characterizes a few features of the stranger. To begin with, the stranger is mobile, he has no possessions (both material and social) and therefore has no set position in society. Without property or kinship, the stranger is truely free to move about and connect freely with people from all works of life. Another attribute of the stranger according to Simmel is objectivity which is enabled since the stranger is not bound by the group's conventions and is therefore free to see it without any bias. The stranger's objectivity allows him to be open and free, both intimate and withdrawn, close yet far from the people of the group.
All these features of the stranger make him, Georg Simmel holds, an important function in society like carrying out tasks that no one else can do or hold conversations that cannot be held between two full, non-stranger, members of the group.