Actually this triggers for me, something which has been trying to break the surface for a while, First think of the above as biological in nature and that which is not purely biological, is then biological extension. The sense of self I would venture to say is a necessity at all levels of organized biology, it is something that is not in one place but is somewhat of an illusion triggered say by a critical mass or critical complexity where the interconnections and interdependencies demand a sense of center in order to relate their needs to this level of a totality, or perhaps it is the complexity of interdependencies and interconnects which communicates constantly and it is this constant communication which is the sense of self, but is found throughout the organism a various levels yet, all connected in the organisms as a totality. Now what has proved to be a most successful plan, the biological organism as a self, it continues along this biological adventure as biological extension/s, you are now belonging and communicating with other people as your interconnections and interdependencies begin forming from childhood on. Does this not strike you as the logical progression of organism and quite as natural in its extension?
Just an added thought: Seeing as it is the conscious subject that bestows meaning upon the world, is it not logical that the meaning he has given to context is the very materials of this social construct of self.