This article sets out a defence of the concept of equity based on conscience by tracing its development from the earliest cases, by establishing that a conscience is something objective and not subjective, and by demonstrating that the idea of conscience provides a coherent central principle for equitable doctrines. Equity is based on a methodology identified by Aristotle in his Ethics which seeks to mitigate the rigour of abstract rules, and also on the idea of conscience. Contrary to most of the assumptions made in the academic commentary on equity, a conscience is an objectively constituted phenomenon. This understanding of a conscience is a commonplace across our culture in sources as disparate as the work of Freud and Kant, in Shakespe...