The following two clips are from the 1989 Film Wittgenstein, directed by
It seems to me that profound implications follow from the realization that the self is public, not private. If our language, thought, and sense of self is essentially embedded in our culture and our relations with others, the implications of that are truly far reaching.
An isolated Cartesian self, principally self-focused and inward looking is a very different creature from an essentially public self, embedded in a world and a culture, created and shaped by relationships. The political implications of this are enormous. Think about policies that assume a world of Cartesian egos as opposed to policies that assume fundamentally relational and public selves.
I think our relationships to others differ on each model just as significantly. If I am fundamentally a Cartesian atomistic self then my chief problem is self-discovery and I must do this by shutting the world "out there" off and looking within. But if I am a relational public self - the goal might still be self-discovery, but with and through discovering others. Relationships with others here are primary not secondary. This is critically important.