Speaking of identity, we may as easily speak of language or any other indefinitely-extensible and recursively self-generating symbolic system of information definition, encoding, compression and self-propagation. Language is always and already that discontinuous difference and dissociative experience that simultaneously facilitates and creates us as Subjects in, through and as communication (or culture) while also implicitly alienating us from ourselves and each other.
The many binary issues of Self and Other, of inside and outside represent foundational ontological symmetries, only intelligible in as much as they exist through language – for both those who seek to inhabit the manifold quicksilver insecurities of self-identity and for those seeking to explain it.
The issue at the base of this problem (and it is, on any mature assessment of our fractured world, a profound and difficult problem) is not that we do not possess sufficiently sophisticated models or frameworks and behavioural or idiomatic templates of (or for) human being. The issue is that no such closure exists, no such ontological definition or clarity through which Self and Other might be either existentially or analytically differentiated. Identity is the problem.