Johannes Nikolaus Tetens

Johannes Nikolaus Tetens (16 September 1736 – 17 August 1807) was a German-Danish philosopher, statistician, and scientist. He is sometimes referred to as the "German Locke" due to similarities between his major work, *Philosophische Versuche über die menschliche Natur und ihre Entwickelung* (1777), and the writings of John Locke. Tetens is considered to have been an influence on Immanuel Kant. Born in Tetenbüll, Duchy of Schleswig (then part of Denmark–Norway), Tetens studied mathematics and physics at the Universities of Rostock and Copenhagen, earning his MA in 1759 and PhD in 1760. From 1760 to 1765, he taught philosophy and physics at the University of Bützow. During this period, he wrote extensively on various subjects. After engaging with David Hume's work, Tetens played a role in popularizing Hume's ideas in the German-speaking world, and is thought to have introduced Kant to phenomenalistic thought and the empiricism/transcendence dualism. In 1776, Tetens became a Professor of Philosophy at the University of Kiel. However, from the 1790s onwards, he embarked on a distinguished career in Danish public service, holding significant positions in finance and state administration in Copenhagen. Alongside his administrative duties, Tetens continued his academic pursuits, focusing on pure mathematics and its applications, particularly in actuarial mathematics. His 1785-1786 work, *Einleitung zur Berechnung der Leibrenten und Anwartschaften*, is considered a foundational text in actuarial science, introducing the concept of a risk measure and offering insights into mathematical statistics.