The concept of ability breeds discrimination. On the basis of empirical evidence and other intangible aspects of human existence, the authors submit, that the theory of centrality governs the understanding of canons of criminal jurisprudence asymmetrically more than the theory of marginality. It is in this light that the insanity defence needs substantial, if not total, reconstruction. The article characterises mental disability with reference to the concept of responsibility in criminal law underlining the essential variance in the perception and construction of the defence.  The authors, on one hand, highlight the quandary of the present-day approach by underlining the invasion of the most basic rights such as that of equality, non-discrimination and the right to access justice and self-determination, while on the other hand, dwell on the glaring inconsistencies in the law and procedure in this area. Finally, the authors reason that the critical disability viewpoint requires us to avoid adopting any exclusionary action, more so on the basis of rationality that the majority commands. The focus must not be to place people beyond criminal adjudication but to improve rehabilitation services and expand the understanding of subjective defences of mens rea. This is what the disability discourse stands for.