From 1760 to 1765, he taught philosophy and physics ("natural philosophy" at that time) at the University of Bützow [de] (in Bützow, Mecklenburg-Western Pomerania). During this decade, he wrote many treatises on various subjects, ranging from the color of the sky to the existence of God through the origins of languages (see e. g. references in Johann Christian Poggendorff, 1863). After this polygraphic formation period, Tetens goes back to more fundamental enquiries: after having read David Hume's work, he popularized it throughout the German-speaking world.