‘in a Kind of Mad Way’: a Historical Perspective on Evidence and Proof of Mental Incapacity

[This article examines the evidential and procedural aspects of claims based on mental incapacity in English courtrooms in the ‘long’ 18 century. It employs a frame the author has termed ‘manifest madness’ to analyse how such claims were articulated and elaborated at trial in this period. This analysis reveals, first, the substantive significance of the accused’s conduct; second, the part played by ordinary people; and third, the role of common knowledge of ‘madness’ in evidence and proof of mental incapacity for criminal law purposes. By reference to the law on what would now be called unfitness to plead, automatism and intoxication, this article demonstrates the utility of the ‘manifest madness’ frame for understanding the evidential and procedural practices attendant to mental incapacity claims in this period. The article then considers the insights this historical analysis provides into current criminal practices for proving mental incapacity.]