The Mathematics of Polemic in John Napier’s Plaine Discovery

John Napier of Merchiston (1550–1617) is famous as the inventor of logarithms and one of Scotland’s most revered mathematicians. Previous research has regarded his theological and mathematical endeavours as either distinct or linked in ways which do not withstand scrutiny. This chapter provides an outline of the mathematical content of Napier’s biblical commentary A Plaine Discovery of the Whole Revelation of Saint John, identifying that work as the sixteenth century’s most developed attempt to provide mathematical certainty to religious claims. Napier’s work emerged from an intellectual context in which thinkers increasingly identified mathematics with exactitude. Nevertheless, this chapter demonstrates that Napier’s true intention was not to discover mathematical patterns in history but to impose them where none truly existed. Napier’s commentary employed mathematical and historical enquiry only to reinforce polemical arguments. Indeed, Napier saw no inherent value in history and reduced the past to a mathematically precise pattern which he believed would allow him to predict the future. Napier’s methodology and results have hitherto been widely misunderstood, which has led to misconceptions about their legacy. The following seeks to correct those errors and further the scholarly understanding of Napier’s work, its impact and place within late-sixteenth–century intellectual traditions.