The Mental Capacity Act 2005 and the practice carried out in its name, sit in a precarious place following a House of Lords Select Committee review. The concern with greater implementation of the Act, as signalled by the House of Lords, risks silencing more significant concerns with the Act. On one level, the House of Lords echoes the Law Commission in accepting mental incapacity as an issue which required and requires a legally sanctioned response. On a more nuanced level, the Act invites healthcare practitioners and others to adopt a particular lens for understanding the self or patient, a lens which bioethical discourse may challenge, endorse or ignore. This thesis seeks to critically engage with these two aspects of the Act from both an ethical and practical dimension. A framing of contemporary practice in the context of prevailing historical mental health and bioethical discourses, facilitates the identification of mental capacity as receptive to a narrative bioethics approach. The papers in this thesis challenge the credibility of the MCAâs current understanding of capacity, itself predicated on an inconsistent understanding of the process of assessment. In doing so, this thesis suggests that an understanding of mental capacity grounded in the activity of narrative identity can inform a more nuanced understanding of the self, the assessor of capacity and the bioethicist, which is attentive to the tensions in practice by acknowledging values, relations of power and epistemic limitations. In opposition to any search for the ârightâ way which offers certainty in dealing with incapacity, this thesis proposes a disposition of humility which resists closure and promotes ethical enquiry.