Between Morality and Efficacy: Reclaiming the Natural Law Theory of Lon Fuller

This article clarifies the relationship between the work of Lon Fuller and the natural law tradition in jurisprudence through a critical engagement with Kristen Rundle's book, Forms Liberate: Reclaiming the Jurisprudence of Lon L Fuller (Hart, 2012). I argue that Fuller's theory engages squarely with the central concern of natural law thought: namely, the idea of law as a rational standard. However, Fuller fails to recognise the full implications of his theory for the role of moral factors in determining legal validity.