This quote poignantly encapsulates the elusive nature of self-understanding and the inherent barriers that exist within human identity. It suggests that while we may momentarily glimpse an understanding of who we are, this insight is ultimately fleeting and incomplete. The idea that we grow increasingly opaque to ourselves as time progresses highlights the paradox of self-awareness—it becomes both deeper and more confusing as we age and experience more of life. The mention of "our own incoherence" reflects the fragmented and often contradictory nature of the self, challenging the notion that one's identity is a fixed, coherent entity.

Furthermore, the statement reveals a profound isolation inherent in human existence. The boundary we cannot cross into another's being underscores the ultimate solitude of personal experience. Intriguingly, it claims that this boundary is impenetrable precisely because we fail to fully access ourselves. It presents the self as both a locked room and a missing key, meaning that self-knowledge is not only difficult to achieve but perhaps fundamentally impossible. This resonates with existential and postmodern ideas that question the stability of identity and highlight the fragmented, ever-changing, and elusive nature of the human self.

In light of this, the quote invites reflection on the limits of introspection and empathy. It implies that understanding others fully is restricted by the impossibility of understanding oneself fully. This paradox challenges us to accept uncertainty about our core identity while fostering humility about the perceptions we hold of others. It is a meditation on human disconnect, the mystery of consciousness, and the profound enigma of always striving to know both ourselves and those around us.