[I]f we are ourselves by way of being-in-the-world, and if the world already is mostly as the being-in-the-world of other people, then our selves must be constituted to a large degree by others. And this is exactly so. As Heidegger says, we are as a being-dependent-on-each-other, or being signed over to one another (aufeinander angewiesen sein). This is the sense in which Heidegger's conception of our sociality is both deeper and less totalistic than that of the social constructionists. On the one hand, it is not that we are an object made by others, but rather that in everyday life, in our work and in the way entities show up for us, we are those others. The being of human beings only emerges as a shared kind of being. On the other hand, since we are not simply constructs, but ways of being, there are modalities of our being by way of which we can resist and exert a counter-force against the dominance of others in our being ourselves.
For these reasons, Heidegger calls the ability we have to be a self the "one" (das Man, generic personal pronoun)—a set of already established social roles, or more precisely, well-established interpretations of things that are linked to fairly clearly delineated sets of human activities and purposes. Heidegger even calls our everyday self the "one's-self" (das Man-selbst), and he claims that we are to a large degree substitutable for each other in the roles that constitute this self.
