Polynomial algebra applied main work taught until 1785 at Kiel. The book Einleitung zur Berechnung contains an extensive synthesis of previous work on the subject, is recognized by actuaries. Philosophische Versuche über die menschliche Natur und ihre Entwickelung. Johannes Tetens was professor of physics at Bützow University, was appointed professor of philosophy in 1776 at the University of Kiel. The Philosophische Versuche is an essentially investigation of the origin.